NEOPENTYL GLYCOL

NEOPENTYL GLYCOL

CAS No. : 126-30-7
EC No. : 204-781-0

Synonyms:
2,2-Dimethylpropane-1,3-diol; NPG; 2,2-Dimethyl-1,3-propanediol; Neopentyl glycol; 126-30-7; 2,2-Dimethylpropane-1,3-diol; 2,2-DIMETHYL-1,3-PROPANEDIOL; Dimethylolpropane; 1,3-Propanediol, 2,2-dimethyl-; Neopentanediol; Neopentylene glycol; Neopentylglycol; Neol; Hydroxypivalyl alcohol; Dimethyltrimethylene glycol; NPG Glycol; 2,2-Dimethyltrimethylene glycol; NEO; UNII-QI80HXD6S5; 2,2-Dimethyl-1,3 propanediol; NPG; EINECS 204-781-0; Propanediol, 2,2-dimethyl-, 1,3-; AI3-05739; 2,3 propanediol; 1,3-Dihydroxy-2,2-dimethylpropane; 2,2-Dimethyl-1,3-propanediol, 99%; 2,2-Bis(hydroxymethyl)propane; 2,2-dimethylolpropane; EC 204-781-0; 4-01-00-02551 (Beilstein Handbook Reference); 2,2-dimethyl-1,3-propandiol; 2,2-dimethylpropan-1,3-diol; 2,2-dimethyl 1,3-propanediol; 2.2-dimethyl-1,3-propanediol; 2,3-Dimethyl-1,3-propanediol; 2,2-dimethyl -1,3-propanediol; 2,2-dimethyl-1,3-propane diol; 2,2-dimethyl-propane-1,3-diol; 1,3-propandiol, 2,2-dimetil-; 2,2-Dimetil-1,3-propandiol; 2,2-Dimetiltrimetilen glikol; Dimetilolpropan; Dimetiltrimetilen glikol; Hidroksipivalil alkol; Neol; Neopentandiol; Neopentilen glikol; NPG; 2,2-Dimetilpropan-1,3-diol; Propandiol, 2,2-dimetil-, 1,3-; [ChemIDplus] Dimetilol propan; [CAMEO] 1,3-Dihidroksi-2,2-dimetilpropan; [ICSC] 2,2-Dimetil-1,3-dihidroksipropan; 2,2-Dimetilolpropan; 2,2-Dimetil-1,3-propandiolo; Dimetilolpropano; Neopentilene glicole; Neopentilglicole; Neopentilglikol; Neopentylglykol; Pentaglycol; 2,2-Dihydroxy-2,2-dimethylpropane; 2,2-Dimethyl-1,3-dihydroxypropane; NPG; 2,2-Dimethylpropane-1,3-diol 126-30-7; 2,2-Dimethyl-1,3-Propanediol; NPG glycol; 2,2-Dimethyl-1,3-propanediol; 2,2-Dimethylpropane-1,3-diol; 1,3-Dihydroxy-2,2-dimethylpropane; Neopentylglycol; 2,2-Dimethyl-1,3-propanediol; 2,2-dimethyl-1,3-propanediol cyclic phosphorochloridate; 2,2-dimethyl-1,3-propanediol cyclic phenylphosphonate; [1′,3′-(2′,2′-dimethylpropylene)]-2-iodo-3-octyl-5-thienylboronate; cyclic carbonate; 2,2-dimethyl-1,3-propanediol bis(cyclic-2,2-dimethyltrimethylene phosphite); neo; 1,3-Propanediol, 2,2-dimethyl- [ACD/Index Name]; 126-30-7 [RN]; 2,2-Dimethyl-1,3-propandiol [German] [ACD/IUPAC Name]; 2,2-Dimethyl-1,3-propanediol [ACD/IUPAC Name]; 2,2-Diméthyl-1,3-propanediol [French] [ACD/IUPAC Name]; 2,2-dimethylpropane-1,3-diol; 2,2-Dimethylpropane-1,3-diol; NPG; 2,2-Dimethyl-1,3-propanediol; Neopentyl glycol; 126-30-7; 2,2-Dimethylpropane-1,3-diol; 2,2-DIMETHYL-1,3-PROPANEDIOL; Dimethylolpropane; 1,3-Propanediol, 2,2-dimethyl-; Neopentanediol; Neopentylene glycol; Neopentylglycol; Neol; Hydroxypivalyl alcohol; Dimethyltrimethylene glycol; NPG Glycol; 2,2-Dimethyltrimethylene glycol; NEO; 204-781-0 [EINECS]; 4-01-00-02551 [Beilstein]; MFCD00004685 [MDL number]; Neopentanediol; Neopentyl glycol [Wiki]; Neopentylene glycol; Neopentylglycol; NPG Glycol; Propanediol, 2,2-dimethyl-, 1,3-; UNII-QI80HXD6S5; 1,3-Dihydroxy-2,2-dimethylpropane; 2, 2-Dimethyl-1, 3-propanediol; 2,​2-​dimethylpropane-​1,​3-​diol; 2,2-Dimethyl-1,3 propanediol; 2,2-Dimethyl-1,3-dihydroxypropane; 2,2-Dimethyltrimethylene glycol; 2,3-Dimethyl-1,3-propanediol; 2-ethylpropane-1,3-diol; Dimethyltrimethylene glycol; Hydroxypivalyl alcohol; Neol; NPG; propane-1,3-diol, 2,2-dimethyl-; 1,3-Propanediol, 2,2-dimethyl-; Dimethylolpropane; Neopentanediol; Neopentylene glycol; 2,2-Dimethyl-1,3-propanediol; Dimethyltrimethylene glycol; Hydroxypivalyl alcohol; NPG; Neol; 1,3-Dihydroxy-2,2-dimethylpropane; 2,2-Dimethyl-1,3-dihydroxypropane; 2,2-Dimethylpropane-1,3-diol; NPG Glycol; 2,2-Dimethyltrimethylene glycol

Neopentyl Glycol

Neopentyl glycol (IUPAC name: 2,2-dimethylpropane-1,3-diol) is an organic chemical compound. Neopentyl glycol is used in the synthesis of polyesters, paints, lubricants, and plasticizers. When used in the manufacture of polyesters, it enhances the stability of the product towards heat, light, and water. By esterification reaction with fatty or carboxylic acids, synthetic lubricating esters with reduced potential for oxidation or hydrolysis, compared to natural esters, can be produced.

Reactions
Neopentyl glycol is synthesized industrially by the aldol reaction of formaldehyde and isobutyraldehyde. This creates the intermediate hydroxypivaldehyde, which can be converted to neopentyl glycol with either excess formaldehyde or by palladium on carbon hydrogenation. [2]
Neopentyl glycol is used as a protecting group for ketones, for example in gestodene synthesis.
A condensation reaction of neopentyl glycol with 2,6-di-tert-butylphenol gives CGP-7930.
Organoboronic acid esters of neopentyl glycol are useful in the Suzuki reaction[3]

Research
Neopentyl glycol has been reported that plastic crystals of neopentyl glycol exhibit a colossal barocaloric effect (CBCEs), which is a cooling effect caused by pressure-induced phase transitions. The obtained entropy changes are about 389 joules per kilogram per kelvin near room temperature. This CBCE phenomenon is likely to be very useful in future solid-state refrigeration technologies.

4 rabbits were gavaged with 1000 -1500 mg/kg bw unlabelled neopentyl glycol and excretion of the test substance and their metabolites via urine was determined the following 24 hr (pooled data). After oral application 62% (range 53-67%) of the applied dose was found in the 24-hr urine as the conjugate of glucuronic acid indicating rapid absorption. Only 1.9% of the applied dose was excreted as 3-hydroxy-2,2-dimethylpropionic acid and 0.7% as unchanged neopentyl glycol. Conclusion: Rapid absorption of the test substance after oral exposure followed by conjugation with glucuronic acid and excretion via urine.

IDENTIFICATION: Neopentyl glycol is a crystalline solid. It has a sweetish odor. It is very soluble in water. USE: Neopentyl glycol is an important commercial chemical. Tt is used in the production of a plasticizers and resins. EXPOSURE: Workers who use neopentyl glycol may breathe in vapors or have direct skin contact. The general population is not likely to be exposed to neopentyl glycol. If neopentyl glycol is released to the environment, it will be broken down in air. It is not expected to be broken down by sunlight. It will move slowly into air from moist soil and water surfaces. It is expected to move through soil. It will not be broken down by microorganisms, and is not expected to build up in fish. RISK: Data on the potential for neopentyl glycol to produce toxic effects in humans were not available. Neopentyl glycol does not cause skin irritation or allergic skin reactions in laboratory animals. Drowsiness, staggered gate, and increased breathing rate occurred in laboratory animals after an extremely high oral dose. No toxic effects were observed following repeated oral exposure to high doses. Slight irritation of the respiratory tract was observed in laboratory animals following repeated exposure to very high air levels of neopentyl glycol. No toxic effects were observed in laboratory animals at lower air levels. No evidence of infertility, abortion, or birth defects was observed in laboratory animals exposed to very high oral doses before and during pregnancy. Data on the potential for neopentyl glycol to cause cancer in laboratory animals were not available. The potential for neopentyl glycol to cause cancer in humans has not been assessed by the U.S. EPA IRIS program, the International Agency for Research on Cancer, or the U.S. National Toxicology Program 14th Report on Carcinogens. 

Neopentyl glycol is the main glycol in powder polyester formulations ... These polyesters are used, for example, in the automotive, domestic appliance, and general industries. Neopentyl glycol is also widely used in solvent borne polyester paints for coil coatings, cans, automotive paints, aerospace and transportation applications, and for other stoving enamels.
The aldol addition of isobutyraldehyde (2-methylpropanal) and formaldehyde gives hydroxypivaldehyde (3-hydroxy-2,2- dimethylpropanal), which is then reduced to neopentyl glycol. ... Both aldol addition and subsequent reduction are exothermic. Hydroxypivaldehyde can be reduced either by a crossed Cannizzaro reaction with equimolar amounts of formaldehyde and a base, or by catalytic hydrogenation.
Impurities may include neopentyl glycol monoformate, neopentyl glycol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol, and the cyclic acetal from the reaction of hydroxypivaldehyde and neopentyl glycol.

IDENTIFICATION AND USE: Neopentyl glycol (NPG) is a solid. It is used in chemical synthesis, and in polyester manufacture. An insect repellent. HUMAN STUDIES: There are no data available. ANIMAL STUDIES: Neopentyl glycol was not irriating to skin in rabbits, and non sensitizing to the skin in the Murine Local Lymph Node Assay. Neopentyl glycol was practically non-toxic in acute studies in rats and guinea pigs. No treatment-related, adverse findings were observed at clinical examinations, clinical pathology and pathology up to a dose level of 1000 mg/kg bw/d in 90 day oral gavage studies in rats. In other rat study reproductive performance of the parent generation and development of the F1 generation were not affected after oral application of dose levels up to 1000 mg/kg bw/day. In male rats single i.p. injection of 2000 mg/kg bw resulted in a mid level of ataxia but no loss of righting reflex. Neopentyl glycol had no mutagenic activity in Salmonella typhimurium TA 100, TA 1535, TA 98, TA 1537, or in Escherichia coli WP2 uvrA tested with and without metabolic activation at dose levels up to 5000 ug/plate. Neopentyl glycol was not mutagenic in the HPRT locus assay under in vitro conditions in CHO cells in the absence and the presence of metabolic activation.

Neopentyl glycol's production and use in the production of plasticizers and polyesters and as a modifier of alkyd resins may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 1.27X10-2 mm Hg at 25 °C indicates neopentyl glycol will exist solely as a vapor in the atmosphere. Vapor-phase neopentyl glycol will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 44 hours. Neopentyl glycol does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. If released to soil, neopentyl glycol is expected to have very high mobility based upon an estimated Koc of 1. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 3.1X10-7 atm-cu m/mole. Neopentyl glycol is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Utilizing the Japanese MITI test, 1.2% of the Theoretical BOD was reached in 2 weeks indicating that biodegradation is not an important environmental fate process in soil or water. If released into water, neopentyl glycol is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. A BCF range of 0.3-0.5 suggests bioconcentration in aquatic organisms is low. Hydrolysis is expected to be an important environmental fate process since this compound contains functional groups that hydrolyze under environmental conditions (pH 5 to 9). Occupational exposure to neopentyl glycol may occur through inhalation and dermal contact with this compound at workplaces where neopentyl glycol is produced or used. Use data indicate that the general population is not likely to be exposed to neopentyl glycol. 

Neopentyl glycol's production and use in the production of plasticizers and polyesters and as a modifier of alkyd resins(1) may result in its release to the environment through various waste streams(SRC).
TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a structure estimation method(2), indicates that neopentyl glycol is expected to have very high mobility in soil(SRC). Volatilization of neopentyl glycol from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 3.1X1-07 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). Neopentyl glycol is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.27X10-2 mm Hg at 25 °C(3). Utilizing the Japanese MITI test, 1.2% of the Theoretical BOD was reached in 2 weeks(4) indicating that biodegradation is not an important environmental fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a structure estimation method(2), indicates that neopentyl glycol is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 3.1X10-7 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 122 and 890 days, respectively(SRC). According to a classification scheme(4), a BCF range of 0.3-0.5(5) suggests bioconcentration in aquatic organisms is low(SRC). Utilizing the Japanese MITI test, 1.2% of the Theoretical BOD was reached in 2 weeks(5) indicating that biodegradation is not an important environmental fate process in water(SRC).
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), neopentyl glycol, which has a estimated vapor pressure of 1.27X10-2 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase neopentyl glycol is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 44 hrs(SRC), calculated from its rate constant of 8.7X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Neopentyl glycol does not contain chromophores that absorb at wavelengths >290 nm(4) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

AEROBIC: Neopently glycol has been identified as considered nonbiodegradable in a relatively short time frame(1). Neopentyl glycol, present at 100 mg/L, reached 1.2% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test(2).
ANAEROBIC: Neopentyl glycol was 1% biodegraded following a lag of >60 days when incubated with an anaerobic digesting sludge from the Reading Sewage Works, Berkshire, UK(1).
The rate constant for the vapor-phase reaction of neopentyl glycol with photochemically-produced hydroxyl radicals has been estimated as 8.7X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 44 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Neopentyl glycol is expected to undergo hydrolysis in the environment due to the presence of functional groups that hydrolyze under environmental conditions(2). Neopentyl glycol does not contain chromophores that absorb at wavelengths >290 nm(2) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

Application: Powder Coatings Resins
Sustainability performance:
Biomass balanced Neopentyl Glycol
Using a biomass balance approach, BASF is replacing a certain amount of fossil raw materials with renewable feedstock
The method is subject to third party certification (REDcert2)
Neopentyl glycol is the industry standard glycol component in high-quality polyester resins for industrial coatings and fiberglass-reinforced plastics applications. Most polyester resin formulations contain NPG as the sole glycol component, or it is used in conjunction with a modifying glycol to achieve desired properties.

Neopentyl glycol and Eastman PTA (Purified Terephthalic Acid) are the primary components for polyester powder coating resins. Eastman NPG delivers the overall toughness, stain and detergent resistance, and outdoor weathering performance required of coil coatings for appliances and products for exterior applications. Gel coats containing unsaturated polyesters made from NPG and Eastman PIA (Purified Isophthalic Acid) provide excellent weatherability and water and stain resistance.
Eastman NPG is also used in polyester polyols for polyurethane coatings for the automotive, industrial maintenance, transportation, and aerospace markets.
In the United States, neopentyl glycol may be lawfully used as a reactant for coatings and other products intended for use in contact with foods under specific federal food additive regulations.

Eastman Neopentyl glycol is available in three forms:
Platelets in bags that exhibit excellent caking stability on storage.
Bulk molten shipped in tank trucks that require a heated tank for storage.
Eastman NPG 90 glycol, a liquid at or above 38°C containing 90 parts NPG and 10 parts water, is delivered in bulk and can be stored at a much lower temperature than molten NPG.

Applications/uses of Neopentyl glycol
Adhesives/sealants-B&C
Architectural coatings
Auto OEM
Auto refinish
Automotive
Building materials
Coil coatings
Construction chemicals
Equipment & machinery
Inks
 
Intermediates
Lubricants
Paints & coatings
Polycarbonate
Polymer modification
Process additives
Protective coatings
Textile
Wind energy
Key attributes
Excellent thermal stability for low resin color
Excellent weathering
Good chemical and stain resistance
Good chemical, stain, and humidity resistance
Good hardness/flexibility balance
Ideal glass transition temperature range
Outstanding powder flow and fluidization characteristics
Outstanding weathering
Rapid reactivity during esterification and cure

2,2-Dimethyl-1,3-propanediol may be used in the synthesis of:
• 2,2-dimethyl-1,3-propanediol cyclic phosphorochloridate[1]
• 2,2-dimethyl-1,3-propanediol cyclic phenylphosphonate[1]
• [1′,3′-(2′,2′-dimethylpropylene)]-2-iodo-3-octyl-5-thienylboronate[2]
• cyclic carbonate[3]
• 2,2-dimethyl-1,3-propanediol bis(cyclic-2,2-dimethyltrimethylene phosphite)[1]

A BCF range of 0.3-0.5 was calculated in fish for neopentyl glycol at 10 ppm using carp (Cyprinus carpio) which were exposed over an 6-week period(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).
Using a structure estimation method based on molecular connectivity indices(1), the Koc of neopentyl glycol can be estimated to be 1(SRC). According to a classification scheme(2), this estimated Koc value suggests that neopentyl glycol is expected to have very high mobility in soil(SRC).
The Henry's Law constant for neopentyl glycol is estimated as 3.1X10-7 atm-cu m/mole(SRC) developed using a fragment constant estimation method(1). This Henry's Law constant indicates that neopentyl glycol is expected to volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 122 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 890 days(SRC). Neopentyl glycol's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). Neopentyl glycol is is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 1.27X10-2 mm Hg(3).

Neopentyl glycol was detected at a concentraiton of 14.7 ug/L in an industrial landfill leachate sampled Decemeber 1996. It was not detected in in an industrial effluent from a petrochemical plant taken in July 1996, January 1997, or March 1997 (landfill leachate); detection limit = 1.0 ug/L(1).
According to the 2016 TSCA Inventory Update Reporting data, 14 reporting facilities estimate the number of persons reasonably likely to be exposed during the manufacturing, processing, or use of neopentyl glycol in the United States may be as low as 10 workers and as high as 500 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).
NIOSH (NOES Survey 1981-1983) has statistically estimated that 6957 workers (1200 of these are female) were potentially exposed to neopentyl glycol in the US(1). Occupational exposure to neopentyl glycol may occur through inhalation and dermal contact with this compound at workplaces where neopentyl glycol is produced or used. Use data indicate that the general population is not likely to be exposed to neopentyl glycol(SRC).
Neopentyl glycol has two primary hydroxyl groups. Neopentyl glycol is a white material in flakes. Neo is used in saturated polyesters for powder coatings, coil coatings and other stoving enamels, unsaturated polyesters for gel coats and reinforced plastics and in esters for synthetic lubricants.

Uses of Neopentyl glycol
Neopentyl glycol (NPG) is used primarily in base resins for coatings. Important uses are also found in hydraulic fluids, synthetic lubricant oils, greases, metal-working fluids and aircraft engine lubricants. Other outlets include textiles, pharmaceuticals, pesticides, plasticisers and petroleum. Neopentyl glycol is shipped as flake, molten and slurry.

Technology
There are two main routes to Neopentyl glycol using isobutyraldehyde and formaldehyde. In one, the raw materials react with a strongly alkaline catalyst to form Neopentyl glycol. But, large amounts of formate salts are formed as byproduct and the process is only economically viable when a profitable use is found for the formate.
In a second and more common process, the aldolisation reaction is carried out in the presence of an amine catalyst. This is further hydrogenated in the presence of a catalyst and the molten Neopentyl glycol is solidified by means of a flaking roll, or a crystallising or cooling belt.

Health and safety
Neopentyl glycol is a white, crystalline solid with a mint-like odour. Finely dispersed particles form explosive mixtures in air and it reacts violently with oxidants.

Outlook
Global demand growth is forecast at 3.1%/year to 2010. Regionally, consumption will rise by 6%/year in Asia-Pacific, 3.5%/year in Africa, Asia/Middle East and eastern Europe, 2.2%/year in the Americas, 2%/year in western Europe and Australia/New Zealand, and 1.3%/year in Japan.
Powder coatings based on Neopentyl glycol show improved impact and scratch resistance, and high gloss. Synthetic lubricants made from Neopentyl glycol provide good lubricity and reduced corrosivity. Both of these uses will grow over 5%/year to 2010.
Shahid Rasuli in Bandar Imam, Iran, will start production at a 12,000 tonnes/year plant in 2007. Mitsubishi Chemical and Mitsubishi Gas formed a joint venture in September 2005 to produce and sell polyvalent alcohols, and they may raise Neopentyl glycol capacity to 50,000 tonnes/year.

Neopentyl glycol (IUPAC name: 2,2-dimethylpropane-1,3-diol) is an organic chemical compound. It is used in the synthesis of polyesters, paints, lubricants, and plasticizers. 
When used in the manufacture of polyesters, it enhances the stability of the product towards heat, light, and water. 
By esterification reaction with fatty or carboxylic acids, synthetic lubricating esters with reduced potential for oxidation or hydrolysis, compared to natural esters, can be produced.