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Propargyl alcohol, a reactive liquid that protects steel surfaces against corrosion in strong acids such as hydrochloric and sulfuric acid, is used in acid pickling and oil well acidizing and carries both a triple bond and an alcohol group in the same molecule. The product ranges from colorless to light yellow and has a geranium-like odor; its CAS number is 107-19-7 and its molecular formula is C₃H₄O. It is miscible with water in all proportions. Because it is toxic and flammable, it should be used only by trained personnel and with strict safety measures.
2-Propyn-1-ol, an acetylenic alcohol used at very low concentrations as a secondary brightener and leveler in nickel plating baths, adsorbs on the cathode surface, refines crystal growth, reduces roughness and helps produce a bright, smooth deposit; it is therefore usually chosen together with primary brighteners such as saccharin. The same triple bond structure also makes the product valuable as an acid corrosion inhibitor, as an additive that limits hydrogen embrittlement in steel and as a component of soldering fluxes.
Ethynyl carbinol, a building block used as an intermediate in the synthesis of pharmaceuticals, agrochemicals and preservatives, takes part in the preparation of sulfonamide drugs such as sulfadiazine and of fosfomycin, in agrochemicals such as clodinafop-propargyl and propargite, and in the production of IPBC, the mold inhibitor used in paints, coatings and wood; it is also present as a stabilizer in chlorinated solvents. Buyers should verify purity, water content and storage conditions from the product documents. This product can be supplied from ATAMAN KİMYA; for technical information and requests, contacting ATAMAN KİMYA is recommended.
WHAT IS PROPARGYL ALCOHOL?
Propargyl alcohol, systematically named prop-2-yn-1-ol and represented by the formula HC≡C–CH₂OH, is the simplest acetylenic primary alcohol. Its structure contains a terminal triple bond and a hydroxymethyl group attached to it. These two reactive sites make the substance a versatile chemical building block that can behave both as an alcohol and as a terminal alkyne.
At room temperature it is a clear, mobile liquid ranging from colorless to pale straw yellow. Its odor resembles geranium, and the odor threshold is reported as about 0.15 ppm. It is lighter than water, with a relative density of about 0.95–0.97. It is miscible with water, ethanol, ether and acetone.
The main industrial route is the reaction of acetylene with formaldehyde over a copper catalyst (Reppe synthesis). In this process the principal product is 2-butyne-1,4-diol; propargyl alcohol forms as a by-product at about 5% and is separated by distillation.
A patented method also obtains propargyl alcohol and formaldehyde by decomposing butynediol at 130–180 °C over a copper acetylide catalyst. This method does not require high acetylene pressure, and yields of 75–94% and gas chromatography purity above 99% have been reported.
The commercial product is mostly offered at 98–99.9% purity. BASF reports a minimum of 99.3% and some Chinese producers a minimum of 99.5–99.6%; values such as a minimum of 98% are seen in laboratory grades. The grades called “anhydrous” on the market are also low-water versions of the same chemical.
Production is concentrated in a handful of large companies and mainly in China. The annual capacity of one of the largest Chinese producers is reported as about 3,000 tonnes. The global market is estimated at a few tens of millions of dollars per year; pharmaceuticals, agrochemicals, corrosion inhibitors and plating additives are the main user groups.
Propargyl alcohol should not be confused with other substances that have similar names. Allyl alcohol (CAS 107-18-6) has a double bond and propyl alcohol (1-propanol, CAS 71-23-8) is a saturated alcohol; both have different properties. Propargyl bromide, propargyl chloride, propargylamine and propargyl acrylate are separate chemicals derived from propargyl alcohol.
In some catalogs, the oxyethylated derivatives of propargyl alcohol also appear under similar names. These are separate products used in nickel plating and corrosion inhibition and carry their own CAS numbers. It is therefore important to verify the CAS number as well as the product name when ordering.
Because it is a hazardous substance, its use requires serious precautions. In the harmonized EU classification it is listed as a flammable liquid, toxic if swallowed, in contact with skin and if inhaled, causing severe skin burns and harmful to aquatic life with long-lasting effects. It can polymerize uncontrollably in the presence of heat, light, bases and oxidizers.
This risk is real. In 2018 at a chemical plant in France, a drum of propargyl alcohol kept for a long time above 30 °C polymerized, exploded and caused a fire. The incident shows that storage temperature and packaging age are decisive for safety.
COMMON PRODUCT AND CHEMICAL NAMES OF PROPARGYL ALCOHOL:
Propargyl Alcohol
Propargylic Alcohol
2-Propyn-1-ol
Prop-2-yn-1-ol
2-Propynol
Prop-2-ynol
3-Propynol
Propynol
Propynyl Alcohol
2-Propynyl Alcohol
Ethynyl Carbinol
Ethynylcarbinol
Ethynylmethanol
Acetylene Carbinol
Acetylenyl Carbinol
Hydroxymethylacetylene
1-Hydroxy-2-propyne
3-Hydroxy-1-propyne
3-Hydroxypropyne
1-Propyn-3-ol
1-Propyn-3-yl Alcohol
Propiolic Alcohol
Agrisynth PA
107-19-7
Most of these names express the same substance in different naming systems. Prop-2-yn-1-ol is the systematic name that follows international rules. 2-Propyn-1-ol and 3-propynol are alternative numberings; ethynyl carbinol and ethynylmethanol describe the structure as a derivative of methanol carrying an ethynyl group.
The name propargyl denotes the –CH₂–C≡CH group derived from the propyne root. Compounds carrying the same group, such as propargyl bromide, propargyl chloride or propargylamine, are not synonyms of propargyl alcohol. Spelling variants such as “propinol” are also seen in some catalogs.
Agrisynth PA is a trade name. Codes such as NA 1986 and UN 1986, which appear in the synonym lists of some catalogs, are old transport numbers rather than substance names; the current UN number is 2929. The 107-19-7 in the list is the CAS number of the substance.
Whichever of these names is used in an order, the CAS number should be written next to it. Product properties such as purity, water content and packaging should be verified from the product documents rather than from the name.
CAS NO, EC / EINECS NO AND CHEMICAL IDENTIFICATION OF PROPARGYL ALCOHOL
Product name: Propargyl Alcohol / Prop-2-yn-1-ol
Common abbreviation: PA (used especially in the corrosion literature)
Chemical name: Prop-2-yn-1-ol (2-propyn-1-ol)
CAS No: 107-19-7
EC / EINECS No: 203-471-2
EU index number: 603-078-00-X
Molecular formula: C₃H₄O
Molecular weight: 56.06 g/mol
Structural notation: HC≡C–CH₂OH; SMILES: C#CCO
Chemical class: Acetylenic (alkynyl) primary alcohol
Main functions: Acid corrosion inhibitor, brightener and leveling additive for nickel plating, chemical intermediate, stabilizer for chlorinated solvents
The harmonized EU classification, under index number 603-078-00-X, lists the substance as flammable liquid category 3 (H226), acute toxicity category 3 by the oral, dermal and inhalation routes (H301, H311, H331), skin corrosion category 1B (H314) and long-term aquatic hazard category 2 (H411). Stricter classifications are also seen in supplier documents.
For transport, UN number 2929, class 6.1 and subsidiary hazard class 3 are used. In customs the substance falls under heading 2905.29, which covers unsaturated acyclic alcohols; the detailed customs code should be verified for the product and the country.
Databases also contain records for this substance such as RTECS number UK5075000, US waste code P102 and NSC 8804. These codes complete the identity of the substance but say nothing about product quality.
CAS and EC numbers are needed to match the product with the correct substance. Technical, laboratory and pharmaceutical synthesis grades carrying the same number are distinguished from each other by purity, water and impurity limits. When writing the order, the grade and the required documents should be stated next to the number.
CHEMICAL STRUCTURE AND MOLECULAR PROPERTIES OF PROPARGYL ALCOHOL
The molecule is represented by the formula HC≡C–CH₂–OH. Of the three carbon atoms, the first two are joined by a triple bond and the third carries the hydroxyl group. Because the carbons of the triple bond are sp hybridized, the C≡C–C axis is linear; the hydroxymethyl group sits at the end of this linear unit.
The triple bond consists of one sigma and two pi bonds. This electron-rich region can attach to metal surfaces, coordinate with metals and enter addition reactions. Because the terminal C–H bond is attached to an sp carbon, it is markedly more acidic than in alkanes; with strong bases or metal ions such as copper and silver it can form acetylides.
The hydroxyl group is a primary alcohol. The estimated pKa is around 13.6, so its aqueous solution behaves close to neutral. One product document gives pH 7 for a 50 g/L solution and another gives pH 3 for a 500 g/L solution. This difference arises from the concentration; a single pH value should not be taken as a product property without stating the concentration.
It is a small, polar molecule. The hydroxyl group forms hydrogen bonds; it is therefore miscible with water in all proportions and the logarithm of its octanol-water partition coefficient is about –0.38. This value indicates that the substance stays in the water phase and has a low tendency to accumulate in living organisms.
It is a neutral molecule of covalent character and contains no ionic component. The oxidation states of its carbon atoms differ: the hydroxymethyl carbon is at the alcohol level and the carbons of the triple bond are at the alkyne level. On oxidation it can proceed first to propynal (propiolaldehyde) and then to propiolic acid.
The structure is thermodynamically strained. The triple bond tends to polymerize spontaneously in the presence of heat, light, bases, oxidizers and peroxides. This reaction releases heat and can cause a pressure rise in a closed container.
The combination of the triple bond and the neighboring hydroxyl makes the propargylic position reactive. The hydroxyl group can form carbamates, esters or ethers and can be converted to a propargyl halide with halogens. The triple bond is used in reactions such as Sonogashira coupling and copper-catalyzed azide-alkyne cycloaddition.
Its solubility behavior fits the structure. The hydroxyl and the triple bond raise polarity and the hydrocarbon part is very short; the substance is therefore miscible with water, alcohol and ether but does not dissolve in aliphatic hydrocarbons. It dissolves in chlorinated and aromatic solvents.
In biological systems it is oxidized to propynal by the cytochrome P450 2E1 enzyme. This more reactive aldehyde suppresses aldehyde dehydrogenase and contributes to liver damage. The high toxicity of the substance is associated with this metabolic activation.
PHYSICAL AND CHEMICAL PROPERTIES OF PROPARGYL ALCOHOL
General technical properties:
Values may vary with the manufacturer, grade and measurement method; the information below is for general information only and does not replace the manufacturer’s specific TDS and SDS documents.
Physical appearance: Clear, mobile liquid ranging from colorless to light yellow (straw colored); geranium-like odor
Chemical character: Neutral, polar, acetylenic primary alcohol; terminal alkyne; prone to polymerization with heat, light and bases
Molecular formula: C₃H₄O
Molecular weight: 56.06 g/mol
CAS No: 107-19-7
EC / EINECS No: 203-471-2
Purity (assay): In commercial grades mostly at least 98–99.9% (gas chromatography). For example, TCI reports a minimum of 98.0%, Thermo Scientific a minimum of 98.5%, Merck a minimum of 99.0%, BASF a minimum of 99.3%, some Chinese producers a minimum of 99.5–99.6% and a pharmaceutical intermediate supplier a minimum of 99.65%. These are product-specific example specifications, not a general limit
Density: Relative density at 20 °C is 0.948–0.950; one manufacturer document gives 0.9485. A literature value of 0.963 g/mL at 25 °C and a value of 0.97 in one safety data sheet are also given
Refractive index: n20/D about 1.429–1.435; 1.432 is given most often
Melting point: About –48 to –53 °C according to the documents; –58 °C in one manufacturer document
Boiling point: About 112–115 °C; 113–115 °C is given most often
Flash point: About 33 °C in a closed cup; 36–37.5 °C in an open cup and other methods
Autoignition temperature: About 365 °C
Explosion limits: Lower limit 3.4% and upper limit 70% by volume in air (three documents); 1.9–86.2% in two documents. The difference comes from the source and the measurement method
Vapor pressure: About 1.54 kPa at 20 °C, that is about 11.6–12 mmHg; some databases give 15.6 mmHg
Vapor density: About 1.93–1.94 relative to air
Viscosity: About 1.68 mPa·s at 20 °C
Solubility in water: Miscible in all proportions; one document gives about 1,000 g/L at 20 °C
Solubility in organic solvents: Miscible or soluble in ethanol, ether, acetone, chloroform, benzene and ethyl acetate; slightly soluble in carbon tetrachloride, insoluble in aliphatic hydrocarbons
pH (aqueous solution): About 7 for a 50 g/L solution (TCI), 3 for a 500 g/L solution at 20 °C (Merck). It should not be taken as a single value without stating the concentration
Octanol-water partition coefficient: log Pow about –0.38; –0.35 in one database
pKa: About 13.6 (estimated)
Odor threshold: About 0.15 ppm
Moisture / water content: At most 0.1% in one supplier specification; at most 0.5% by the Karl Fischer method in one laboratory grade. There is no general limit; it depends on the product specification
Formaldehyde: At most 0.1% in one manufacturer specification; formaldehyde is an impurity that comes from the production route
Color: At most 20 Hazen in one manufacturer specification
Stabilizer: One source states that the commercial material contains a stabilizer; the type and amount are not given in most documents and should be asked of the supplier
Decomposition: Stable under normal conditions; may polymerize with heat, light, bases, peroxides and oxidizers. Carbon oxides form in a fire
Reactivity: Incompatible with phosphorus pentoxide, strong acids and bases, oxidizers, amines, isocyanates, acid chlorides and anhydrides; attacks many plastics
Flammability rating: Given as health 4, flammability 3, instability 3 in the NFPA 704 rating
Short Description of Physical Properties
Propargyl alcohol is a liquid that is lighter than water, low in viscosity and quite volatile at room temperature. Its boiling point is around 114 °C. Because its flash point is about 33 °C, it forms vapors that can ignite even in cool environments.
The vapor density is about 1.9 times that of air. Vapors accumulate at ground level and can spread to a distant ignition source. The explosion limits are wide; the lower limit is given as 1.9–3.4% and the upper limit as 70–86% depending on the source.
Storage of the product in the cold, for example at 0–10 °C or 2–8 °C, is recommended. This recommendation has nothing to do with solidification, because the melting point is very low. The real reason is that the substance is sensitive to heat and air.
Small differences are seen between documents. The melting point is given as –48 to –58 °C, the flash point as 33 to 37.5 °C and the relative density as 0.948 to 0.97. The differences come from the measurement method, temperature, purity and literature source. Binding values should be sought in the product’s certificate of analysis.
Water content is one of the most important indicators of quality. No safety data sheet gives a universal water limit; manufacturers state their own limits, for example at most 0.1%. An expression such as “anhydrous” therefore carries meaning only if it is given in the product document together with a water limit.
HOW DOES PROPARGYL ALCOHOL WORK AT THE MOLECULAR LEVEL?
The action of propargyl alcohol rests on mechanisms that vary with the application: adsorption and film formation on a metal surface, direction of crystal growth on the cathode surface, triple bond and hydroxyl chemistry as an intermediate, and slowing of the decomposition chain in chlorinated solvents. What they all have in common is the triple bond of the molecule.
Acid corrosion inhibition
In strong acid the steel surface becomes positively charged and acid anions approach the surface. Propargyl alcohol attaches to the surface through the pi electrons of the triple bond and the oxygen of the hydroxyl, and slows both anodic and cathodic reactions. It is therefore regarded as a mixed-type inhibitor.
In a study on iron in sulfuric acid, each adsorbed propargyl alcohol molecule was calculated to displace about three water molecules on the surface. The free energy of adsorption was found to be about –31.2 kJ/mol. After long immersion, a film with saturated hydrocarbon character was seen on the surface.
The real protection comes from the polymerization of the molecules attached to the surface over time. A hydrophobic film forms and limits the access of acid to the metal. In one study the thickness of this film was determined as about 11.3 Å; about 97% protection was found at 0.05% by weight in 4 M HCl at 80 °C.
The effect is strong in concentrated acid and may weaken as the acid is diluted. In a study on stainless steel, an inhibition efficiency of 98.3–99.9% was reported in HCl with 0.05–0.10% propargyl alcohol by volume.
Metal ions and auxiliary substances change the result. Copper and chromium ions increase the effect of propargyl alcohol against both corrosion and hydrogen uptake; Fe³⁺ markedly reduces the effect, especially at FeCl₃ levels above 2.5%. Arsenic ion increases inhibition but also accelerates hydrogen uptake.
Synergists such as iodide increase surface coverage. In 0.5 M sulfuric acid on chromium alloy steel, the best result was found with the combination of 10 mM propargyl alcohol and 0.01% potassium iodide. Adsorption followed the Langmuir isotherm.
Brightener and leveler in nickel plating
In nickel plating, secondary (Class II) brighteners are unsaturated organic compounds. Propargyl alcohol adsorbs on the cathode surface through its pi electrons and slows the reduction of nickel ions at protruding, high current density points. Pits are thus filled, the surface is leveled and the grain structure is refined.
These compounds are not used alone. Class II additives increase internal stress and brittleness; sulfur-containing Class I brighteners such as saccharin balance this. In one study, triple-bond additives such as propargyl alcohol were tested separately and their brightness and leveling effects were compared.
One patent reported that propargyl alcohol alone provided leveling at 0.15 g/L but skipped plating in low current density regions. Its ethoxylated derivatives gave better results. A range of 0.01–0.5 g/L is given for total acetylenic additives.
As a chemical intermediate
The terminal hydrogen couples with aryl or vinyl halides under palladium and copper(I) catalysis in the Sonogashira coupling. The same terminal alkyne gives a triazole ring in copper-catalyzed azide-alkyne cycloaddition (CuAAC, “click chemistry”). Propargyl alcohol is an easily available building block in these reactions that can also be attached through its alcohol group.
The hydroxyl group is converted to propynyl butylcarbamate with butyl isocyanate. This intermediate is iodinated in aqueous medium at low temperature to give IPBC. In agrochemicals such as clodinafop-propargyl and propargite, propargyl alcohol supplies the propargyl (prop-2-ynyl) group of the molecule.
Oxidation gives propynal and propiolic acid, and halogenation gives propargyl bromide and 3-chloropropyne. Databases also list sulfadiazine, isophytol, idoxuridine and fosfomycin among the products prepared from propargyl alcohol.
Stabilization in chlorinated solvents
Trichloroethylene decomposes with metal, moisture and heat to form acid. When propargyl alcohol is added together with an auxiliary such as pyrrole at 0.005–1% by weight, preferably 0.05–0.5%, this decomposition is slowed.
In an accelerated test, acidity rose to 494 ppm in the unadditized solvent but stayed at 93 ppm in the solvent containing 0.1% propargyl alcohol, 0.05% pyrrole and a very small amount of amine. When propargyl alcohol was used alone, the effect remained limited.
IN WHICH SECTORS IS PROPARGYL ALCOHOL USED?
Propargyl alcohol is a specialty chemical that is small in volume but valuable in function. Its main uses are in metal protection, plating and chemical synthesis. The fields below are those actually documented in the sources examined.
Oil and gas
In well acidizing and stimulation work, concentrated HCl corrodes steel pipes, tubing and drilling equipment. Propargyl alcohol and its derivatives are used in inhibitor packages added to these acids. It has also been tested against iron corrosion in aqueous media containing carbon dioxide.
Metalworking and acid pickling
In the pickling of steel in HCl or H₂SO₄ it is used to reduce metal loss and hydrogen uptake. Because hydrogen uptake can cause brittleness in steel, propargyl alcohol is also mentioned in limiting hydrogen embrittlement.
Galvanic and electroplating
It is a brightener and leveling additive in nickel baths. Sources also state that it is used as a component in electroless plating baths. It is often present at low amounts as part of commercial additive packages.
Pharmaceuticals and biotechnology
As a synthesis intermediate it is used in preparing sulfonamide-type antibacterials (sulfadiazine), fosfomycin and some antiviral and other drug precursors. It appears not as an ingredient in the final drug but as a step in the production chain.
Agriculture
The propargyl group is present in the structure of herbicides such as clodinafop-propargyl and acaricides such as propargite. Propargite is not approved as a product in the EU; its production and use status differs from country to country.
Paints, coatings and wood protection
It is present not as a direct ingredient but as the raw material of the IPBC mold inhibitor. IPBC is used as a dry-film preservative in paints and coatings, as a wood preservative and in some adhesives.
Chemistry and fine chemicals
It is used in organic synthesis as an acetylenic three-carbon building block. Propargyl halides, propargyl esters and ethers, propiolic acid and various alkyne derivatives are obtained from this building block.
Polymers and plastics
It is used in preparing monomers, crosslinkers and functional polymers that contain alkynes. Sources list it as a polymer modifier; giving polymers new functionality by click chemistry is one of the current examples in this area.
Solvent and stabilizer
It is used to stabilize chlorinated hydrocarbons, especially trichloroethylene, against decomposition in vapor degreasing. It is also mentioned as a solvent for cellulose acetate. This use has shrunk because trichloroethylene use is restricted in many regions.
Electronics, aerospace and other special fields
It is reported to be used as a soldering flux component, as an additive in aerospace paint strippers and as a laboratory reagent. In some sources it also appears as a soil fumigant; the US Environmental Protection Agency has not been able to confirm this use.
Widespread use in fields such as food, cosmetics, textiles, paper and detergents was not encountered in the sources examined. Some fields such as water treatment and mining appear on supplier pages but are not supported by independent technical sources.
IS PROPARGYL ALCOHOL USED IN COSMETIC, FOOD AND PHARMACEUTICAL APPLICATIONS?
Short answer: it is not used as an ingredient in cosmetics and food. In pharmaceuticals it appears only as a synthesis intermediate. The three fields are discussed separately below.
Cosmetics
Propargyl alcohol is not a cosmetic ingredient; there is no INCI name defined for a cosmetic function. It causes severe skin burns and can be fatal through absorption via the skin. Its use in leave-on or rinse-off products is therefore unacceptable.
A fragrance raw material database marks the substance as “not for fragrance use”. The cosmetic preservative IPBC is synthesized from propargyl alcohol; however, IPBC is a separate substance and this does not mean propargyl alcohol can be used in cosmetics.
Food
Propargyl alcohol is not a food additive and has no E number. It is not added directly to food. A food and flavor database marks the substance as “not for flavor use”; it is also not included in the Food Chemicals Codex.
No record was found permitting its use in food contact materials either. In food production facilities, the use of this substance should be treated as a technical chemical that must be kept separate from food.
Pharmaceuticals
It is not used as an active or auxiliary substance in medicines. Supplier sources present it as an intermediate used in the synthesis of drugs such as sulfonamide-type antibacterials and fosfomycin. This use is an early step in the production chain.
In this type of use, the intermediate must not carry over into the final product as a residue. Propargyl alcohol has shown mutagenic effects in some tests; pharmaceutical manufacturers therefore control impurities according to international harmonization guidelines. High purity and batch consistency are important in this field.
It is not a substance with a pharmacopoeia monograph; no such monograph was found in the sources examined. The quality of the product to be used in drug synthesis is determined by the specification between the buyer and the manufacturer; the pharmaceutical manufacturing rules of the target country should also be assessed separately.
INDUSTRIAL APPLICATIONS OF PROPARGYL ALCOHOL
The industrial value of propargyl alcohol comes from its triple bond, which lets it attach to metal surfaces, and from the fact that the same bond is a versatile reaction site in chemical synthesis. In the applications below the substance is mostly used not alone but together with auxiliary components. The performance conditions and regulations of each application are separate.
Oil well acidizing and stimulation
The aim is to limit corrosion of steel pipes, tubing and drilling equipment by the concentrated hydrochloric acid used to raise well productivity. Propargyl alcohol and its derivatives are added to acid inhibitor packages for this purpose. One patent describes an inhibitor mixture containing 80–90% propargyl alcohol by weight.
The reason for preferring it is that it gives strong protection at high temperature and in concentrated acid and forms a lasting film on the surface. Halogenated propargyl alcohols, propargyl alcohol adducts and oxyethylated derivatives have also been tested as inhibitors in HCl and carbon dioxide environments. One patent gives levels of 5–20 ppm in a carbon dioxide environment.
The limitation is the high toxicity of the substance and its harm to the aquatic environment. Cinnamaldehyde-based systems and indolizine derivatives have been developed as alternatives that do not use acetylenic alcohol. The effect may fall in dilute acid, and Fe³⁺ build-up can reduce performance.
Steel pickling and hydrogen embrittlement
The aim is to remove the oxide layer on the steel surface with HCl or H₂SO₄ while limiting dissolution of the sound metal and hydrogen uptake. Hydrogen uptake can cause brittleness in high-strength steel. Propargyl alcohol is used as an inhibitor that coats the surface in acid.
In one study, 98.3–99.9% protection was achieved in HCl with 0.05–0.10% propargyl alcohol by volume on 304L stainless steel. Copper and chromium ions increased the effect against both corrosion and hydrogen uptake, while arsenic ion increased inhibition but accelerated hydrogen uptake.
The limitation is the iron ions that build up in the bath in use. Fe³⁺ markedly lowers the effect of propargyl alcohol; the inhibitor level and efficiency must therefore be monitored as the bath ages. Aluminum alloys require a separate assessment.
Nickel plating baths
The aim is to obtain a bright, even nickel deposit and to cover roughness in the underlying surface. Propargyl alcohol and its ethoxylated derivative are used in very small amounts as secondary brighteners together with primary brighteners such as saccharin. Their effect begins with adsorption on the cathode surface.
One study showed that brightness increased markedly when molecules with triple bonds were added. In the patent literature total acetylenic additive is given in the range of 0.01–0.5 g/L, while it is stated that propargyl alcohol used alone skips plating at low current density and ethoxylated derivatives give better leveling.
The limitation is that secondary brighteners increase internal stress and brittleness. They are therefore not used alone and are balanced with a sulfur-containing primary brightener. As the bath ages, feathering or dark areas may form. Alternatives are other acetylenic additives such as 2-butyne-1,4-diol and its ethoxylates.
Pharmaceutical and agrochemical synthesis
The aim is to add a propargyl or alkyne unit to the target molecule. For this purpose propargyl alcohol is used to form esters, ethers and carbamates through the alcohol group or in coupling reactions through the triple bond. Supplier sources give sulfadiazine, fosfomycin and various agrochemicals as examples.
In active substances such as clodinafop-propargyl and propargite, the propargyl group is present directly in the structure. Databases also list isophytol, idoxuridine and propiolic acid among the products prepared from propargyl alcohol.
The reason for preferring it is that it is a small and inexpensive source of an alkyne. The limitations are high toxicity and increased side reactions at low purity. A supplier marketing pharmaceutical intermediates stresses a purity of at least 99.65%. Values such as water, formaldehyde and color are also limited according to the synthesis step concerned.
Biocide (IPBC) production
The aim is to obtain the IPBC mold inhibitor used in paints, coatings, wood preservatives, adhesives, metalworking fluids and some personal care products. In this production propargyl alcohol first reacts with butyl isocyanate and the resulting carbamate is then iodinated. The process is carried out in aqueous medium at low temperature.
IPBC was patented by Troy Chemical in 1975. It is reported to be registered in the EU in the range of 10–100 tonnes per year. This production is the leading indirect contribution of propargyl alcohol to the paint sector.
The limitation is that the process requires process safety because the reaction runs with isocyanate and iodine chemistry. Residual propargyl alcohol and other impurities are monitored in the final product. The quality of the raw material can affect the purity and color of the IPBC.
Stabilization of chlorinated solvents
The aim is to prevent trichloroethylene used in vapor degreasing from decomposing and forming acid under metal, moisture and heat. Propargyl alcohol is added at 0.005–1% by weight, mostly together with auxiliaries such as pyrrole and a very small amount of amine. Its effect alone is limited.
The reason for preferring it is that at low concentration it protects aluminum and steel equipment from acidic decomposition products. The limitation is that this application has shrunk because trichloroethylene use is restricted in many regions. In some regions alternative solvents and closed systems are preferred.
Polymer modification and click chemistry
The aim is to give polymers, resins and surfaces a triple bond function and then to join this function with azide-containing molecules. Propargyl alcohol is the raw material of monomers and modifiers such as propargyl acrylate, propargyl methacrylate and propargyl ether.
Copper-catalyzed azide-alkyne cycloaddition gives a highly selective coupling under mild conditions. It is therefore used in surface functionalization, crosslinking and the development of special coatings. Residual copper, control of toxic monomers and product safety are limiting issues.
Other special applications
It is reported to be used as a soldering flux component, as an additive in electroless plating baths and as an auxiliary substance in aerospace paint strippers. In laboratories it is a research reagent as a three-carbon alkyne building block.
The amounts used in these fields are generally small, and product documents mostly remain within the formulators’ own knowledge. Companies considering use need to obtain product-specific information from the supplier and from the regulations.
POINTS TO NOTE WHEN USING PROPARGYL ALCOHOL
Propargyl alcohol is a highly hazardous chemical. Because it is toxic, absorbed through the skin, flammable and prone to polymerization, strict precautions are needed at every stage. Quality, compatibility and regulation should be considered together.
Main points to note:
• Skin absorption: The liquid is absorbed rapidly through the skin and can be fatal. The NIOSH skin notation is “fatal” for systemic effect. Where contact is possible, suitable gloves, protective clothing and face protection should be used; in case of contact, clothing should be removed and the area washed with plenty of water
• Inhalation: The vapor pressure is high and the odor threshold is low. Work should be done in a closed system under local ventilation; occupational limits vary between 0.2 and 2 ppm depending on the country and in most places also carry a skin notation
• Polymerization: It can polymerize uncontrollably with heat, light, bases, oxidizers and peroxides. Storage temperature should be kept below 30 °C, opened containers should not be kept for long, and they should be kept away from heat sources
• Incompatible substances: It should not be brought into contact with phosphorus pentoxide, strong acids and bases, oxidizers, amines, isocyanates, acid chlorides and anhydrides. Unstable metal acetylides can form with copper, silver and mercury salts in basic medium
• Fire and explosion: The flash point is about 33 °C. The vapors are heavier than air and form an explosive mixture over a wide range. Ignition sources should be removed, grounding and bonding should be applied, and spark-free tools and explosion-proof equipment should be used
• Material compatibility: Stainless steel, glass and phenolic-lined containers are preferred. Clean, rust-free steel is accepted for short-term use. Aluminum, rubber and epoxy coatings are advised against; the substance attacks many plastics
• Water and impurities: Water content, formaldehyde and color vary with the product. The grade suitable for the intended use should be verified with a certificate of analysis
• Eyes: The undiluted liquid can cause lasting corneal damage in the eye. Full protective goggles and, where necessary, a face shield should be used, and an eye wash station should be present in the area
• Environment: It is toxic to fish and water fleas. It should not be released into drains, soil or waterways
• Waste: It is considered hazardous waste in many countries. In the United States it is on the acute hazardous waste list (P102). Waste should be disposed of by licensed companies
• Training and records: Workers should be trained, exposure should be monitored and an emergency plan should be prepared
• Regulation: Classification, labeling, transport, occupational exposure and KKDİK/REACH obligations should be checked according to the target country
This section has been prepared for general information purposes. The current safety data sheet and technical data sheet of the product to be used should be taken as the basis.
STARTING FORMULATION APPROACHES FOR PROPARGYL ALCOHOL
The examples below have been prepared to show at a conceptual level how propargyl alcohol can be evaluated in formulation and process development. They are not verified commercial recipes, production instructions or final formulas that comply with regulations.
Propargyl alcohol is a toxic, flammable, corrosive substance prone to polymerization. For this reason, application details such as complete component tables, mixing order, temperature and time are not given in this section. Only the low use levels reported in published sources, the variables to be evaluated and the criteria are presented.
Every study should be carried out in closed systems that comply with the safety data sheet, with trained personnel and in authorized laboratories. Ready-made commercial inhibitor and plating additive packages often provide a safer starting point than working with the pure substance. Regulatory, safety and environmental assessment should be made by experts in every application.
EXAMPLE 1: SCREENING OF PROPARGYL ALCOHOL INHIBITOR CONCENTRATION FOR STEEL IN ACIDIC MEDIUM
Purpose: To examine the effect of propargyl alcohol concentration, temperature and synergist on corrosion rate and hydrogen uptake in hydrochloric or sulfuric acid, using carbon steel or stainless steel coupons.
Starting approach:
Acid medium: about 15% HCl or 0.5 M H₂SO₄, chosen according to the application and kept constant
Propargyl alcohol: in the literature about 0.05–0.10% by volume (stainless steel in HCl) or 0.05% by weight (4 M HCl at 80 °C); screened with graded concentrations
Synergist: potassium iodide at about 0.01% or a small amount of copper or chromium ion; tried as a separate variable
Metal coupon, surface preparation and immersion time: kept constant
Temperature: screened in steps over the actual range of the application
Application approach:
• Coupons are cleaned by a standard method and weighed, immersed in the test solution at controlled temperature and reweighed at the end of the period, and the corrosion rate is calculated as g/m²·h
• Mixed-type action, adsorption and film formation are examined with polarization and impedance measurements; the surface is imaged by scanning electron microscopy
• If needed, hydrogen uptake is followed by hydrogen permeation or loss of mechanical properties
• The effect of accumulated Fe³⁺ in the acid is tested separately, because efficiency may fall in aging baths
• Results are compared with commercial inhibitors and alternatives of lower toxicity
Safety and quality note: The work should be done only in a fume hood or closed system, with butyl rubber gloves, a face shield and goggles. Hydrogen gas evolution and acid vapor must be taken into account, and the used acid solution must be disposed of as waste in accordance with regulations. If possible, a ready-made inhibitor solution should be used instead of the pure substance.
EXAMPLE 2: EVALUATION OF ACETYLENIC ADDITIVE LEVEL IN A NICKEL PLATING BATH
Purpose: To examine the effect of low concentrations of propargyl alcohol or its ethoxylated derivative on brightness, leveling, ductility and plating at low current density in a bright nickel plating bath.
Starting approach:
Main bath (nickel salts and buffer): chosen according to the application and kept constant
Primary brightener (such as saccharin): in the literature up to about 5 g/L; kept constant
Propargyl alcohol or its ethoxylate: in the literature about 0.05–0.20 g/L (patent); about 3 mg/L for the ethoxylate in one study; screened so that total acetylenic additive does not exceed 0.01–0.5 g/L
2-Butyne-1,4-diol or its ethoxylate: about 5–10 mg/L for comparison
Amino-propyne derivative: in the literature about 0.001–0.003 g/L to remove aging defects; evaluated as a separate variable
Temperature, pH and current density range: kept constant
Application approach:
• Appearance, brightness and leveling effect are evaluated over a wide current density range with Hull cell panels
• Ductility and internal stress are measured; it is observed that brittleness rises as the additive increases and that balance with the primary brightener is needed
• The bath is aged per ampere-hour and feathering, dark areas and low current density defects are recorded
• Additive consumption is analyzed periodically and compared with the performance of a commercial additive package
Safety and quality note: Instead of pure propargyl alcohol, an ethoxylated or ready-made dilute additive solution should be chosen if possible. Ventilation and closed dosing over the bath are recommended. Wastewater containing additives and nickel should be treated in accordance with regulations; nickel salts may also be sensitizing and carcinogenic and require a separate assessment.
EXAMPLE 3: EVALUATION OF PROPARGYL ALCOHOL BATCH QUALITY IN PHARMACEUTICAL OR AGROCHEMICAL SYNTHESIS
Purpose: To compare the effect of differences in purity, water, formaldehyde, color and stabilizer between supplier batches on conversion, selectivity and by-product formation in a synthesis step that uses propargyl alcohol as an intermediate.
Starting approach:
Propargyl alcohol batches: at least three suppliers or batches; selected by purity (for example 98%, 99% and 99.5% and above) and water content
Model step: the user’s own process, for example carbamate or ester formation, Sonogashira coupling or copper-catalyzed azide-alkyne cycloaddition; conditions kept constant
Input parameters to monitor: purity, Karl Fischer water, formaldehyde, color, refractive index, stabilizer type
Output parameters: conversion, selectivity, by-product profile, color and final product purity
Application approach:
• Input analyses for each batch are recorded by gas chromatography, Karl Fischer and color measurement
• The same model step is repeated with each batch; conversion, product purity and by-product profile are compared
• It is determined whether water and stabilizer affect the reaction, especially in systems containing isocyanate, metal catalyst and base
• Based on the results, a purchasing specification, for example minimum purity and maximum water, is set
Safety and quality note: The work should be done only with trained personnel, in a closed system and with the polymerization risk taken into account. Batches should be stored cold and below 30 °C, and opened containers should not be kept. In pharmaceutical production, carry-over of the intermediate into the final product as a residue and control of genotoxic impurities should also be planned separately.
SIMILAR PRODUCTS AND ALTERNATIVES TO PROPARGYL ALCOHOL
Looking for an alternative to propargyl alcohol requires first clarifying the purpose of use. The properties sought in an acid inhibitor, a nickel brightener and a synthesis building block are very different. The substances below can take on a similar function or are structurally close, but none replaces another in every application. The aim is often to achieve the same performance with lower toxicity.
PROPARGYL ALCOHOL AND 2-BUTYNE-1,4-DIOL
2-Butyne-1,4-diol is a symmetrical acetylenic diol that carries two hydroxyl groups. It is a hygroscopic solid at room temperature and is obtained by combining acetylene with formaldehyde by the Reppe method. Propargyl alcohol also forms in this production as a by-product, at about 5%.
In nickel plating both substances are used as secondary brighteners and in most baths they are present together in their ethoxylated forms. Because butynediol is a solid, its vapor pressure and inhalation risk are lower; propargyl alcohol is a liquid and is preferred for its leveling effect. In acid inhibition, butynediol does not readily take the place of propargyl alcohol.
PROPARGYL ALCOHOL AND 2-METHYL-3-BUTYN-2-OL
2-Methyl-3-butyn-2-ol is a tertiary alcohol that carries a terminal alkyne. Its melting point is about 3 °C and its boiling point about 104 °C. The dermal LD50 in rabbits is reported as about 1,420 mg/kg; this value points to toxicity far below that of propargyl alcohol.
The substance is used as a plating additive and as an acetylene carrier. In organic synthesis it is also known as a source that replaces acetylene in Sonogashira coupling and from which the protecting group can be removed afterward. In syntheses that need primary alcohol chemistry, it cannot replace propargyl alcohol.
PROPARGYL ALCOHOL AND 3-BUTYN-2-OL
3-Butyn-2-ol is a secondary alcohol analog of propargyl alcohol with an added methyl group. Its boiling point is about 110 °C and its flash point about 34 °C. It is used in vitamin A synthesis and in Sonogashira and Pauson-Khand reactions.
Although structurally close, its toxicity is also similar; one source gives the LD50 as about 57 mg/kg. It therefore brings no gain in safety. The choice depends on the chiral center of the target molecule and the synthesis plan.
PROPARGYL ALCOHOL AND ALLYL ALCOHOL
Allyl alcohol is a similar small alcohol that carries a double bond instead of a triple bond, and it too is toxic, flammable and irritating. Many occupational exposure values set for propargyl alcohol in the past were based on analogy with allyl alcohol.
This substance does not give the same performance in acid inhibition and nickel plating, because the film that polymerizes on the surface arises mainly from the triple bond. It is not a substitute that can be chosen for safety reasons; it is only a member of the same chemical family.
PROPARGYL ALCOHOL AND PROPARGYL ALCOHOL ETHOXYLATES
Ethoxylated propargyl alcohol is a derivative in which ethylene oxide has been added to the hydroxyl group. In nickel plating it is reported to give better leveling and not to skip plating in low current density regions. It has also been tried as an inhibitor at 5–20 ppm in carbon dioxide environments.
The derivative is less volatile and often easier to handle. However, because it is a separate substance, its CAS number, regulatory status and toxicity data must be verified separately. In commercial additive packages the ethoxylate is mostly supplied mixed with other components.
ACID INHIBITOR ALTERNATIVES
Cinnamaldehyde-based systems are among the most common alternatives that contain no acetylenic alcohol. One patent describes a cinnamaldehyde-based inhibitor for concentrated HCl, finding acetylenic alcohols harmful to the environment. Indolizine derivatives have also been tried in 15–20% HCl on N80 steel without propargyl alcohol synergy.
What these alternatives have in common is the effort to reduce the high toxicity of propargyl alcohol and its harm to the aquatic environment. On the other hand, at high temperature and in concentrated acid propargyl alcohol is still the reference component. Most commercial packages therefore work by reducing propargyl alcohol rather than removing it entirely.
OTHER SOURCES OF PROPARGYLATION IN SYNTHESIS
The bromide and chloride derivatives, namely propargyl bromide and 3-chloropropyne, are reactive halides used to attach the propargyl group directly. They are obtained from propargyl alcohol, but they are alkylating and irritating substances. If esterification or carbamate formation through the alcohol group is possible, propargyl alcohol is preferred directly as a building block.
Amines and esters also offer different coupling strategies. The choice is determined by the type of bond desired, the reaction conditions and product safety. No building block can replace another in all synthesis plans.
QUALITY CONTROL AND PURCHASING CRITERIA FOR PROPARGYL ALCOHOL
For propargyl alcohol, quality control covers stability and impurity profile as well as classic parameters such as purity and water. The binding specification is always found in the technical data sheet and certificate of analysis of the manufacturer supplying the product. Main parameters:
• Identity and grade: The product name and the CAS number 107-19-7 should be written together. The grade, for example technical, synthesis or laboratory grade, should be stated clearly
• Purity: Determined by gas chromatography. In commercial specifications at least 98–99.9% is mostly seen; TCI reports a minimum of 98.0%, Thermo Scientific a minimum of 98.5%, Merck a minimum of 99.0%, BASF a minimum of 99.3%, some Chinese producers 99.5–99.6% and a pharmaceutical intermediate supplier a minimum of 99.65%
• Water content: Measured by the Karl Fischer method. One supplier reports at most 0.1% and one laboratory grade at most 0.5%. There is no universal limit; water can be critical in pharmaceutical and organometallic synthesis
• Formaldehyde: An impurity from the production route. One manufacturer specification gives at most 0.1%. Formaldehyde matters both for safety and for later reactions
• Color: One manufacturer reports at most 20 Hazen. The substance varies from colorless to light yellow; yellowing can be a sign of aging and polymerization
• Density and refractive index: At 20 °C the relative density is about 0.948–0.950 and n20/D about 1.429–1.435. They can be used for identity verification and quick acceptance checks
• Stabilizer: There is information that the commercial material contains a stabilizer; the type and amount are not given in most documents. It should be asked of the supplier because it can interfere in synthesis or plating
• Metal ions and other impurities: Ions such as iron and copper can affect plating, acid inhibition and the tendency to polymerize. Limits should be requested according to the intended use
• Batch information: Production date, batch number, packaging type and net quantity should be asked for. Analysis should be repeated on batches that have been stored for a long time
• Documents: SDS, TDS, batch-specific certificate of analysis and transport information should be requested. For pharmaceutical or agrochemical synthesis, a quality statement and the impurity control framework should also be asked about
The manufacturer’s typical values should not be confused with the binding specification. Solids-specific parameters such as particle size and bulk density do not apply to this liquid. Test methods, for example gas chromatography and Karl Fischer, should be agreed in advance between buyer and seller.
STORAGE AND TRANSPORT OF PROPARGYL ALCOHOL
Propargyl alcohol should be stored in a cool, dry, well-ventilated place away from ignition sources, in its tightly closed original packaging. The substance is sensitive to heat, light and air; many suppliers therefore recommend storage under inert gas. The store should be locked, with a leak-proof floor, and suitable for toxic and flammable liquids.
The temperature limit varies by document. TCI recommends 0–10 °C; CDH, Molekula and Thermo Scientific recommend 2–8 °C; Merck gives a range of 2–30 °C, and another source states below 30 °C. The reason for cold storage is not freezing but the risk of polymerization. The manufacturer’s own instruction should be taken as the basis.
An incident report from France describes a polymerization explosion in a drum kept for a long time above 30 °C. Among the lessons drawn, keeping opened drums under nitrogen and consuming them within a few weeks, and storing unopened drums below 30 °C for less than about one year, stand out.
Suitable packaging materials are clean stainless steel, glass and phenolic-lined containers. Aluminum, rubber and epoxy coatings are advised against; the substance attacks many plastics. BASF states that it offers 0.5 kg, 186 and 190 kg drums and bulk shipment; one manufacturer reports 180 kg drums, and Indian suppliers report 35, 50 and 200 kg drums.
Incompatible substances are phosphorus pentoxide, strong acids and bases, oxidizers, amines, isocyanates, acid chlorides and anhydrides. Contact with copper, silver and mercury salts can lead to the formation of explosive metal acetylides. The store should be kept separate from food and feed areas.
In transport, most documents classify it as UN 2929, class 6.1 (subsidiary hazard 3), toxic liquid, flammable, organic, n.o.s. The packing group is given as I or II depending on the document; TCI, CDH, Sigma-Aldrich and Molekula state group I, and Loba, Henan Haiyuan and Thermo Scientific state group II. The number UN 1986 / NA 1986 also appears on some pages.
These differences may depend on the product form, purity and assessment method. For every shipment, the current safety data sheet of the supplier concerned and the ADR, IMDG or IATA regulations should be taken as the basis. The Kemler number is given as 63.
During transport the packaging should be leak-proof, the labels complete and the vehicle protected from heat. It should not be left in the sun for long in summer, and refrigerated transport should be considered where possible. In bulk shipment it should be verified that tanks and lines are clean, moisture-free and of compatible material.
SAFETY INFORMATION ON PROPARGYL ALCOHOL
Propargyl alcohol appears in many supplier documents as a highly hazardous substance. It is toxic, absorbed through the skin, corrosive, flammable and can polymerize uncontrollably. The information below is intended for the general reader and does not replace the product-specific safety data sheet.
Main hazards:
• Classification: The harmonized EU classification lists flammable liquid category 3 (H226), acute toxicity category 3 if swallowed, in contact with skin and if inhaled (H301, H311, H331), skin corrosion category 1B (H314) and long-term aquatic hazard category 2 (H411). Some suppliers use stricter classification; for example H300, H310, H330, H341, H372 and, in one supplier, H350 are seen
• Acute toxicity: The oral LD50 in rats is reported as about 20–70 mg/kg depending on the document and the dermal value in rabbits as about 16–88 mg/kg. The inhalation LC50 in rats is about 873 ppm over two hours. There is a skin notation; absorption of the liquid through the skin can be fatal
• Skin and eyes: The undiluted liquid can cause second-degree burns within minutes and lasting damage to the eye. It has a lachrymatory effect; the odor threshold is about 0.15 ppm
• Respiratory: Vapors irritate the nose, throat and lungs. Liver and kidney effects have been reported with repeated exposure. Occupational limits vary by country: NIOSH and ACGIH 1 ppm (skin), Germany and Switzerland 2 ppm, and the recommendation of the Health Council of the Netherlands 0.2 ppm
• Long-term effects: In the inhalation study of the US National Toxicology Program in rats and mice, the nose was the primary target, and some evidence of carcinogenic activity was reported in male rats. The substance was found mutagenic in some bacterial tests
• Fire and explosion: The flash point is about 33 °C, the vapors are heavier than air and form an explosive mixture over a wide range. In a fire, carbon dioxide, alcohol-resistant foam or dry chemical powder can be used; a strong water jet is not recommended. The NFPA 704 rating is health 4, flammability 3, instability 3
• Reactivity: It can polymerize with heat, light, bases, peroxides and oxidizers. Ignition has been reported on contact with phosphorus pentoxide. Heating in a closed container can lead to a pressure rise and explosion
• Personal protective equipment: Work should be done in a closed system or fume hood. Gloves approved in the safety data sheet with permeation data (for example butyl rubber), full face protection or sealed goggles, protective clothing and, where necessary, respiratory protection should be used. An eye wash station and emergency shower should be present
• Spills: The area should be evacuated, ignition sources shut off and ventilation provided. The spilled material should be collected with an inert absorbent and not released into the sewer. Emergency guides recommend an isolation distance of 50 m for a small spill and 800 m for a tank fire
• First aid: In case of contact, contaminated clothing should be removed immediately, skin and eyes washed with plenty of water for at least 15 minutes, and if inhaled the person moved to fresh air. In every case, medical help and a poison information center should be contacted immediately. Symptoms may appear with a delay
• Environment: The LC50 for fish is reported as about 1.53 mg/L and for water fleas about 3.36 mg/L. It is toxic to aquatic organisms; it should not be released into water, soil or drains
• Waste: In the United States it is on the acute hazardous waste list (P102). Waste should be disposed of by licensed companies in accordance with hazardous waste regulations
This section is for general information only; it does not replace the product-specific SDS.
WHAT SHOULD BE CONSIDERED WHEN BUYING PROPARGYL ALCOHOL?
Propargyl alcohol is a small-volume but critical specialty chemical. The market size is reported to have been about 30–60 million US dollars in 2025, with annual growth of about 3–5% expected. Production is concentrated in companies such as Henan Haiyuan, Dezhou Tianyu and Shandong Donge Fengle in China, and in BASF. The purchasing decision should therefore be assessed in terms of safety and continuity as well as price.
Main points to consider:
• Correct chemical identity: The substance named prop-2-yn-1-ol with CAS number 107-19-7 should be requested. Similarly named products such as propargyl alcohol ethoxylate, 2-(prop-2-ynyloxy)ethanol, 3-butyn-2-ol and propargylamine are different substances
• Quality suited to the intended use: The purity, water, formaldehyde and color limits needed for an acid inhibitor, a plating additive and pharmaceutical synthesis differ. The requirement should be turned into a written specification in advance
• The term “anhydrous”: An anhydrous or low-water grade is meaningful only if it is given in the document together with a water limit. The limit and the measurement method should be seen in the certificate of analysis
• Product documents: Current SDS, TDS, batch-specific certificate of analysis and transport documents should be requested. The classification and packing group in the SDS should be consistent with the shipping documents
• Packaging and logistics: Options range from small laboratory bottles to 190 kg drums and bulk loading. A company authorized for dangerous goods transport, a suitable vehicle and the need for a cold chain should be planned separately
• Batch consistency and shelf life: The production date should be asked, stock turnover planned and opened containers consumed in a short time
• The supplier’s technical support: It is valuable if the supplier can give information on safe handling, storage and inhibitor or additive selection
• Regulation: The substance is subject to the toxic and hazardous substance legislation of the target country, KKDİK and REACH obligations, dangerous goods transport rules and occupational exposure limits. Required permits and registrations should be checked by the buyer
• Total cost of supply: In addition to the unit price, the costs of cold storage, dangerous goods freight, protective equipment, waste disposal and safety training should be taken into account
Before ordering, the product’s safety and specification documents should be reviewed in full, and for critical applications a preliminary trial should be made with a sample.
SUPPLY OF PROPARGYL ALCOHOL FROM ATAMAN KİMYA
Propargyl alcohol is a specialty chemical that carries a terminal alkyne and a primary alcohol and is used in acid corrosion inhibition, nickel plating, pharmaceutical and agrochemical synthesis and IPBC production. Because it is toxic and flammable, documentation and quality verification are especially important when selecting it.
The ATAMAN KİMYA website has more than one product page of a general introductory nature for propargyl alcohol. On the pages the substance is referred to as prop-2-yn-1-ol, propargyl alcohol or propynol, and its areas of use and synonyms are listed.
These pages do not contain product-specific details such as grade, purity, water content, formaldehyde level, packaging, stock, origin or documents. The pages also contain no supply commitment or delivery time information.
On one of the pages examined, the CAS number, EC number and molecular formula of another substance, 2-(prop-2-ynyloxy)ethanol, appear. The identifying data on the pages should therefore not be relied on alone; in the order, the CAS number 107-19-7 and the product name should be written together and confirmed.
One of the pages states that the commercial product contains a stabilizer. Since the type and amount of the stabilizer are not stated, this information should be asked separately from ATAMAN KİMYA before ordering, according to the intended use.
Companies looking for propargyl alcohol for acid inhibition, a plating additive or pharmaceutical synthesis are advised to tell ATAMAN KİMYA in advance the required grade, water and formaldehyde limits, packaging type and necessary documents. This allows product suitability and current supply status to be assessed more reliably.
The current stock status, origin, grade, purity, water and formaldehyde level, stabilizer information, packaging, transport conditions, regulatory compliance and documents of the product should be confirmed with ATAMAN KİMYA before ordering.
Sharing the following information in a quotation request makes it easier to evaluate the right product:
• Sector of use and final application, for example acid inhibitor, nickel plating, pharmaceutical or agrochemical synthesis, IPBC production
• Required grade and purity limit
• Required water content, formaldehyde and color limits
• Stabilizer requirement or expectation of a stabilizer-free grade
• Required CAS number (107-19-7) and, if any, brand or product code
• Estimated order quantity and shipment frequency
• Required packaging type and size, storage and unloading facilities
• Requested documents: SDS, TDS, certificate of analysis and transport documents
• If available, the TDS or analysis information of the current product
Because it is a toxic and flammable substance, the buyer should also check that the receiving and storage conditions comply with the hazardous materials regulations of the target country.
For ATAMAN KİMYA contact details, the contact page on the company’s website can be used.
FREQUENTLY ASKED QUESTIONS ABOUT PROPARGYL ALCOHOL
What is propargyl alcohol?
It is the simplest acetylenic primary alcohol, with the formula HC≡C–CH₂OH. It is a colorless to light yellow, mobile liquid with a geranium-like odor. It is used as an acid inhibitor, a nickel plating additive and an intermediate in pharmaceutical, agrochemical and IPBC synthesis.
What does propargyl alcohol mean?
Its name comes from the propargyl (prop-2-ynyl) group, which carries a triple bond. The systematic name is prop-2-yn-1-ol; it is also called ethynyl carbinol, 2-propyn-1-ol and propynol. Its structure contains a terminal triple bond and a hydroxyl group.
What is the CAS number of propargyl alcohol?
It is 107-19-7. Similarly named products such as ethoxylate, propargylamine or 2-(prop-2-ynyloxy)ethanol have different numbers; the CAS number and product name should be stated together in the order.
What is the EC / EINECS number of propargyl alcohol?
It is 203-471-2. In the harmonized EU classification it appears under index number 603-078-00-X.
What is the chemical formula of propargyl alcohol?
It is C₃H₄O. The molecular weight is about 56.06 g/mol. Its structural notation is HC≡C–CH₂OH or C#CCO.
Is propargyl alcohol used in cosmetics or food?
No. It is not a cosmetic ingredient and has no INCI name; it is not a food additive and has no E number. The cosmetic preservative IPBC is synthesized from propargyl alcohol, but it is a separate substance.
What is the difference between propargyl alcohol and 2-butyne-1,4-diol?
Propargyl alcohol is a volatile liquid with a single hydroxyl group. 2-Butyne-1,4-diol is a hygroscopic solid with two hydroxyl groups and is the main product of the production in which propargyl alcohol forms as a by-product. Both are secondary brighteners in nickel plating, but they are not the same substance.
What is propargyl alcohol used for?
It is used to protect steel in acid media, to give brightness and evenness in nickel plating, to provide an alkyne building block in pharmaceutical and agrochemical synthesis, to produce IPBC and to stabilize trichloroethylene.
In which sectors is propargyl alcohol used?
It is used in oil and gas, metalworking and pickling, galvanic plating, pharmaceuticals, agrochemicals, the paint and wood protection chain, fine chemicals and polymer modification. It is not present as an ingredient in cosmetics and food.
How does propargyl alcohol prevent acid corrosion?
It attaches to the steel surface through the pi electrons of the triple bond and the hydroxyl oxygen and slows both anodic and cathodic reactions. The molecules on the surface polymerize over time and form a hydrophobic film that limits the access of acid to the metal.
What is propargyl alcohol good for?
It reduces metal loss and hydrogen uptake in concentrated acid, gives bright and even plating in a nickel bath and acts in synthesis as a versatile building block with alcohol and alkyne functions.
How does propargyl alcohol work in nickel plating?
As a secondary brightener it adsorbs on the cathode surface and slows the reduction of nickel ions at protruding points. Pits are thus filled, the surface is leveled and the grain structure is refined. Its effect is balanced with primary brighteners such as saccharin.
Is propargyl alcohol soluble in water?
Yes. It is miscible with water in all proportions; it is also miscible or soluble in ethanol, ether, acetone, chloroform and benzene. It does not dissolve in aliphatic hydrocarbons.
How much propargyl alcohol is used in acid inhibition?
In the literature, levels of about 0.05–0.10% by volume in HCl are reported for stainless steel. In well acidizing, an inhibitor mixture based on propargyl alcohol was added at about 0.5–20% of the acid fluid. The real dose depends on temperature, the type of acid and the commercial package.
Is propargyl alcohol a hazardous substance?
Yes, it is highly hazardous. It is toxic if swallowed, in contact with skin and if inhaled, causes severe skin burns and eye damage, is flammable and is harmful to the aquatic environment. Work should be done in a closed system and with suitable protective equipment, and the product-specific SDS should be taken as the basis.
Why can propargyl alcohol be fatal through absorption via the skin?
Because it is a small, polar molecule that mixes with water, it passes rapidly through the skin. The dermal LD50 in rabbits is reported as about 16–88 mg/kg and there is a skin notation. In case of contact, contaminated clothing should be removed, the area washed with plenty of water and medical help obtained immediately.
Is propargyl alcohol registered under REACH?
The substance has a harmonized classification in the EU and notifications exist in the ECHA classification and labelling inventory. The registration number, tonnage band and scope of use should be confirmed from the ECHA database and from the supplier. The situation under KKDİK in Türkiye should be checked separately.
What is the physical appearance of propargyl alcohol?
It is a colorless to light yellow, clear, mobile liquid; the odor resembles geranium. The relative density is about 0.95, the boiling point about 114 °C and the flash point about 33 °C.
What is the UN number of propargyl alcohol?
In most documents UN 2929, class 6.1 (subsidiary hazard 3), is given. The packing group is I or II depending on the document. UN 1986 / NA 1986 is also seen on some pages. The current SDS and transport regulations should be checked for every shipment.
Why are water and formaldehyde important in propargyl alcohol?
Water can disturb the reaction in syntheses containing isocyanate, metal catalyst and base. Formaldehyde is an impurity from the production route and matters both for safety and for later reactions. Limits vary with the supplier, for example at most 0.1%.
What does the price of propargyl alcohol depend on?
It varies with purity, water and formaldehyde limits, packaging, order quantity, and cold storage and dangerous goods transport requirements. The costs of the raw materials acetylene and formaldehyde and the concentration of producers are also influential.
Is there an alternative to propargyl alcohol?
It depends on the use. In nickel plating 2-butyne-1,4-diol and ethoxylates, in acid inhibition cinnamaldehyde-based systems and indolizine derivatives, and in synthesis alkynes such as 2-methyl-3-butyn-2-ol can be evaluated. None replaces another in every application.
How should propargyl alcohol be stored?
It should be stored in a cool, dry, ventilated place away from ignition sources, in a closed original container. Many suppliers recommend storage at 2–8 °C or at most 30 °C under inert gas. Opened containers should not be kept for a long time.
Which documents should be requested when buying propargyl alcohol?
SDS, TDS and a batch-specific certificate of analysis are the basic documents. Depending on the application, a quality statement, transport document and regulatory information should also be requested.
Which technical properties are important when buying propargyl alcohol?
Purity, water content, formaldehyde, color, relative density, refractive index, stabilizer information and impurity profile are important. Packaging, production date and batch consistency should also be asked about.
PROPARGYL ALCOHOL – TECHNICAL SUMMARY
Chemical name: Prop-2-yn-1-ol; propargyl alcohol
Common name: Propargyl alcohol, 2-Propyn-1-ol, Ethynyl carbinol, Propynol, Agrisynth PA
CAS No: 107-19-7
EC / EINECS No: 203-471-2
Molecular formula: C₃H₄O
Molecular weight: 56.06 g/mol
Chemical class: Acetylenic primary alcohol; terminal alkyne
Physical appearance: Colorless to light yellow, clear, mobile liquid; geranium-like odor
Main properties: Relative density about 0.948–0.950 (20 °C), refractive index about 1.429–1.435, boiling point about 112–115 °C, melting point about –48 to –58 °C, flash point about 33 °C (closed cup), vapor pressure about 1.54 kPa (20 °C), miscible with water in all proportions
Main functions: Acid corrosion inhibitor, secondary brightener for nickel plating, synthesis intermediate, stabilizer for chlorinated solvents
Important application areas: Oil well acidizing and steel pickling, galvanic nickel plating, pharmaceutical and agrochemical synthesis, IPBC production, trichloroethylene stabilization, click chemistry and polymer modification
Parameters critical for quality control: Purity, water content, formaldehyde, color, relative density, refractive index, stabilizer, metal ions
Storage: In a cool, dry, ventilated place, in a closed original container; mostly cold and under inert gas; away from heat, light, bases, oxidizers and incompatible substances
Regulation: Under the harmonized EU classification flammable liquid category 3 (H226), acute toxicity category 3 (H301, H311, H331), skin corrosion category 1B (H314) and aquatic chronic category 2 (H411); for transport UN 2929, class 6.1 (3), packing group I or II depending on the document; not used as an ingredient in cosmetics and food; REACH and KKDİK status and permits of use should be confirmed with the supplier and current regulation.
