Quick Search
E422 Glycerol is a sugar alcohol with chemical formula C3H5(OH)3.
E422 Glycerol has three carbon atoms with one hydroxyl group on each.
E422 Glycerol is a colorless, odorless, sweet-tasting, viscous liquid at Standard Ambient Temperature and Pressure (SATP).
CAS: 56-81-5
MF: C3H8O3
MW: 92.09
EINECS: 200-289-5
Synonyms
Emery 912;Glycerin USP;glycerin(mist);Glycerin, anhydrous;Glycerin, synthetic;glycerin,anhydrous;glycerin,synthetic;C3H5(OH)3
Because of its three hydroxyl groups, E422 Glycerol is miscible with water and is hygroscopic in nature.
The E422 Glycerol is found in lipids known as glycerides, where one or more of the hydroxyl groups are esterified with fatty acids.
The most abundant of glycerides are triglycerides (found in animal fats and vegetable oils), the form in which glycerol is most commonly found in nature.
E422 Glycerol is also widely used as a sweetener in the food industry and as a humectant in pharmaceutical formulations.
Modern use of the word E422 Glycerol (alternatively spelled glycerin) refers to commercial preparations of glycerol that are less than 100% purity, typically 95%.
E422 Glycerol is a triol with a structure of propane substituted at positions 1, 2 and 3 by hydroxy groups.
E422 Glycerol has a role as an osmolyte, a solvent, a detergent, a human metabolite, an algal metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite, a mouse metabolite and a geroprotector.
E422 Glycerol is an alditol and a triol.
E422 Glycerol Chemical Properties
Melting point: 20 °C(lit.)
Boiling point: 290 °C
density: 1.25 g/mL(lit.)
vapor density: 3.1 (vs air)
vapor pressure: <1 mm Hg ( 20 °C)
refractive index: n20/D 1.474(lit.)
FEMA: 2525 | GLYCEROL
Fp: 320 °F
storage temp.: Store at +5°C to +30°C.
solubility: H2O: 5 M at 20 °C, clear, colorless
pka: 14.15(at 25℃)
form: Viscous Liquid
color: APHA: ≤10
Specific Gravity: 1.265 (15/15℃)1.262
Odor: Odorless.
PH Range: 5.5 - 8
PH: 5.5-8 (25℃, 5M in H2O)
explosive limit: 2.6-11.3%(V)
Odor Type: odorless
biological source: synthetic (organic)
Water Solubility: >500 g/L (20 ºC)
Thermal Conductivity: 0.285 W/(m·K) at 25 ℃
Sensitive: Hygroscopic
λmax λ: 260 nm Amax: 0.05
λ: 280 nm Amax: 0.04
Merck: 14,4484
JECFA Number: 909
BRN: 635685
Henry's Law Constant: 4.7×106 mol/(m3Pa) at 25℃, Burkholder et al. (2019)
Dielectric constant: 47.0（Ambient）
Exposure limits OSHA: TWA 15 mg/m3; TWA 5 mg/m3
Stability: Stable. Incompatible with perchloric acid, lead oxide, acetic anhydride, nitrobenzene, chlorine, peroxides, strong acids, strong bases. Combustible.
Cosmetic Ingredient Review (CIR): Glycerol (56-81-5)
InChI: 1S/C3H8O3/c4-1-3(6)2-5/h3-6H,1-2H2
InChIKey: PEDCQBHIVMGVHV-UHFFFAOYSA-N
LogP: -2.32
Surface tension: 64mN/m at 20°C
CAS DataBase Reference: 56-81-5(CAS DataBase Reference)
NIST Chemistry Reference: 1,2,3-Propanetriol(56-81-5)
EPA Substance Registry System: E422 Glycerol (56-81-5)
Absorption: ≤0.02 at 280nm in H2O at 0.5M
≤0.07 at 260nm in H2O at 0.5M
Pure E422 Glycerol appears as colorless, odorless and sweet viscous liquid.
Boiling point: 290 ° C, melting point: 17.9 ° C, the relative density: 1.2613.
E422 Glycerol can be miscible with water infinitely.
E422 Glycerol can be dissolved in 11 times ethyl acetate, about 500 times ether.
E422 Glycerolis insoluble in benzene, chloroform, carbon tetrachloride, carbon disulfide, petroleum ether and oil.
Anhydrous E422 Glycerol has a strong water absorption property.
E422 Glycerol is weakly acidic, being able to react with alkaline hydroxide.
For example, E422 Glycerol reaction with copper hydroxide can produce bright blue cupric glycerinate (can be used to identify polyols).
E422 Glycerol can react with nitric acid to generate glyceryl trinitrate, also known as nitroglycerin, being a strong explosive.
Because E422 Glycerol has water absorption property, it is often used as the moisturizing agent of cosmetics, leather, tobacco, food and textile.
E422 Glycerol also has effect on lubricating the intestine, being able to be used for enema or suppository treatment of constipation.
Nitroglycerides have the effect of dilating coronary arteries and can be used to treat angina.
Nitroglycerin can be used as an explosive and propellant.
E422 Glycerol can react with binary acid to generate alkyd resin, widely being used in paints and coatings.
In nature, E422 Glycerol is widely presented in the form of esters.
For example, a variety of animal and vegetable oils are E422 Glycerol carboxylate with hydrolyzing grease being capable to generate fatty acids and glycerol.
At present, one of the major sources of E422 Glycerol is the byproduct of the soap industry (grease is hydrolyzed under alkaline conditions).
The other major source is from petroleum pyrolysis gas, propylene.
E422 Glycerol is the polyhydric alcohol 1,2,3 propanetriol [HOCH2-CH(OH)CH2OH] also known as glycerol.
A clear, colorless, syrupy liquid having a sweet taste.
E422 Glycerol has not more than a slight characteristic odor, which is neither harsh nor disagreeable.
E422 Glycerol is hygroscopic and its solutions are neutral.
E422 Glycerol is miscible with water and with alcohol.
E422 Glycerol is insoluble in chloroform, in ether, and in fixed and volatile oils.
In the animal body, E422 Glycerol may be formed from ingested carbohydrates, from glycogen by glycolysis, and from fats and other lipids by hydrolysis.
Commercially, E422 Glycerol can be produced by a number of methods including microbial fermentation of sugars, as a by-product in the manufacture of soap, or by synthesis from propylene.
Animal and vegetable fats contain about 10 percent by weight of glycerin.
E422 Glycerol is present in animal tissues to the extent of about 1 percent of the body weight.
E422 Glycerol is not an essential nutrient, but it furnishes energy by contributing to the general pool of oxidizable organic compounds.
E422 Glycerol is a sweet-tasting, syrupy liquid.
E422 Glycerol has not more than a slight characteristic odor, which is neither harsh nor disagreeable Glycerol is a trihydric alcohol.
E422 Glycerol is hygroscopic and its solutions are neutral.
E422 Glycerol ,CH20HCHOHCH20H, also known as glycerin and glycyl alcohol, is a clear, colorless, viscous liquid with a sweet taste.
E422 Glycerol is the simplest trihydroxy alcohol and a valuable chemical intermediary.
E422 Glycerol is soluble in water and alcohol, but only partially soluble in ether and ethyl acetate.
E422 Glycerol is used in perfume and medicine,as an antifreeze,and in manufacturing soaps and explosives.
Structure
Although achiral, E422 Glycerol is prochiral with respect to reactions of one of the two primary alcohols.
Thus, in substituted derivatives, the stereospecific numbering labels the molecule with a sn- prefix before the stem name of the molecule.
Uses
E422 Glycerol is used both in sample preparation and gel formation for polyacrylamide gel electrophoresis.
E422 Glycerol increases the density of a sample so that the sample will layer at the bottom of a gel’s sample well.
E422 Glycerol is also used to aid in casting gradient gels and as a protein stabilizer and storage buffer component.
Food industry
In food and beverages, E422 Glycerol serves as a humectant, solvent, and sweetener, and may help preserve foods.
E422 Glycerol is also used as filler in commercially prepared low-fat foods (e.g., cookies), and as a thickening agent in liqueurs.
E422 Glycerol and water are used to preserve certain types of plant leaves.
E422 Glycerol is recommended as an additive when polyol sweeteners such as erythritol and xylitol are used, as its perceived heating effect in the mouth will counteract these sweeteners' perceived cooling effect.
E422 Glycerol is a raw material for the production of nitroglycerin, acetic acid glycerol, surfactants, flavors, alkyds and ester gums.
E422 Glycerol can be directly used in antifreeze, cosmetics, inks, etc.
E422 Glycerol can be used as water-retaining agent (used for bread and cake); carrier solvent (used in flavor, pigment and water-soluble preservative; thickener (used for drink and wine formulation); plasticizer (candy, desert and meat product); sweetener, gas chromatographic fixative.
EEC provides E422 Glycerol can be used for alcoholic beverages, candy, cakes, coating glazing, meat and cheese coating, alcoholic beverages, bakery products, gelatin, gelatin and other sweets.
E422 Glycerol is used both in sample preparation and gel formation for polyacrylamide gel electrophoresis.
E422 Glycerol increases the density of a sample so that the sample will layer at the bottom of a gel sample well.
E422 Glycerol is also used to aid in casting gradient gels and as a protein stabilizer and storage buffer component.
E422 Glycerol is an important basic organic raw material, being widely used in industrial, pharmaceutical and daily life.
There are about 1700 kinds of applications, mainly for medicine, cosmetics, alkyd resin, tobacco, food, sour resin, explosives, textile printing and dyeing and so on.
The demand of E422 Glycerol in alkyd resin, celluloid and explosives exhibits a downward trend.
But its demand in medicine, cosmetics and food will continue to grow.
In previous years, the compositions of E422 Glycerol consumption in China include: 35.7% in paint; 32.6% in toothpaste; 4.8% in cosmetics; 6% in cigarettes, 5.9% in medicine, 4.8% in polyether and 10.2% for the other.
During the manufacture of drugs and cosmetics, E422 Glycerol is widely used to prepare a variety of preparations, solvents, moisture, antifreeze and sweeteners.
The cyclization of glycerol and p-nitroaniline can generate 6-nitroquinoline.
The monostearate obtained from the acidification between glycerol and stearic acid is a kind of excipient, used as the matrix of hydrophilic ointment.
E422 Glycerol can generate acrolein by elimination reaction, and has been used to produce methionine and glutaraldehyde.
The potassium E422 Glycerol phosphate, sodium glycerophosphate, calcium glycerophosphate made from glycerol and phosphoric acid are all used as a nutritional medicine.
Chlorination of E422 Glycerol can generate the intermediate monochloro-propylene glycol for the production of caffeine and guaiacol glycerol ether.
E422 Glycerol can participate in the cyclization and condensation of p-hydroxybenzaldehyde and, 4, 6-trihydroxy-3, 5-dimethyl benzophenone to obtain the expectorant cough medicine Rhododendron.
E422 Glycerol can be condensed with acetone to form 1, 2-isopropylidene glyceride.
E422 Glycerol can be used for the manufacture of shark liver alcohol used for increasing the count of white blood cell.
Nitration of E422 Glycerol can generate glyceryl trinitrate, namely, vasodilator nitroglycerin.
Glycerol can be reacted with 2, 5-diaminoanisole sulfate to give the intermediate 6-methoxy-4, 7-phenanthroline.
E422 Glycerol is also a raw material for the midrange marker 6-methoxy-7-nitroquinoline.
Several quinoline derivatives were obtained from the reaction between glycerol and aromatic primary amines with such reactions being called skraup reactions.
Another major application of E422 Glycerol is the preparation of alkyd resin.
At present, the resin used in the paint around the world includes mainly alkyd resin, acrylic resin, vinyl resin and epoxy resin, among which, alkyd resin paint ranks first in both the United States and Japan.
E422 Glycerol accounts for 42% in the polyol used in the alkyd resin.
E422 Glycerol is easy to digest and non-toxic and can be used as a solvent, hygroscopic agent and vehicle for the food industry.
For the seasoning and coloring food, because the E422 Glycerol is sticky, and can therefore contribute to food molding.
During the rapid freezing of food, E422 Glycerol can be used as a direct medium of heat transfer for food.
E422 Glycerol is also a lubricant for food processing and packaging machinery.
In addition, the application of E422 Glycerol and polyglycerol esters during the manufacture of crispy and margarine products is increasing year by year.
E422 Glycerol can be used in tobacco (mainly cigars) as a humectant to keep the moisture of the tobacco, to prevent embrittlement, and to increase the sweetness of tobacco.
In the case of cigar paper and filter paper, E422 Glycerol is used as a plasticizer in the form of triacetin.
Glyceryl triacetate accounts for one third of the total consumption of glycerol in the tobacco industry.
Between 1970 and 1986, the average annual growth rate of E422 Glycerol production in China was 5.3%, but the average annual growth rate of consumption in the same period was 7%.
In 1983 – 1986, China imported a total of 52,400 tons of E422 Glycerol with the average annual import of 1.31 million tons, accounting for 1/4 of the annual consumption.
E422 Glycerol has been recognized as a non-toxic and safe substance with no harmful effect on human or animal upon oral administration of high-dose of natural glycerol.
Intravenous injection of 5% E422 Glycerol solution to human also causes poisoning phenomenon.
The national Institute of Occupational Safety and Health (NIOSH) provides that the E422 Glycerol content of water, when being higher than 1000mg/L, is harmless to the human body.
Medical
E422 Glycerol is used in medical, pharmaceutical and personal care preparations, often as a means of improving smoothness, providing lubrication, and as a humectant.
Ichthyosis and xerosis have been relieved by the topical use of glycerin.
E422 Glycerol is found in allergen immunotherapies, cough syrups, elixirs and expectorants, toothpaste, mouthwashes, skin care products, shaving cream, hair care products, soaps, and water-based personal lubricants.
E422 Glycerol is used to keep tablets and other solid dosage forms from falling apart.
For human consumption, E422 Glycerol is classified by the FDA among the sugar alcohols as a caloric macronutrient.
E422 Glycerol is also used in blood banking to preserve red blood cells prior to freezing.
Taken rectally, E422 Glycerol functions as a laxative by irritating the anal mucosa and inducing a hyperosmotic effect, expanding the colon by drawing water into it to induce peristalsis resulting in evacuation.
E422 Glycerol may be administered undiluted either as a suppository or as a small-volume (2–10 ml) enema.
Alternatively, E422 Glycerol may be administered in a dilute solution, such as 5%, as a high-volume enema.
Taken orally (often mixed with fruit juice to reduce its sweet taste), E422 Glycerol can cause a rapid, temporary decrease in the internal pressure of the eye.
This can be useful for the initial emergency treatment of severely elevated eye pressure.
In 2017, researchers showed that the probiotic Limosilactobacillus reuteri bacteria can be supplemented with E422 Glycerol to enhance its production of antimicrobial substances in the human gut.
This was confirmed to be as effective as the antibiotic vancomycin at inhibiting Clostridioides difficile infection without having a significant effect on the overall microbial composition of the gut.
E422 Glycerol solutions have been used for the preservation and storage of tissue grafts at ambient conditions as an alternative to frozen storage.
E422 Glycerol has also been incorporated as a component of bio-ink formulations in the field of bioprinting.
The E422 Glycerol content acts to add viscosity to the bio-ink without adding large protein, saccharide, or glycoprotein molecules.
E422 Glycerol is on the World Health Organization's List of Essential Medicines for its use in treating atopic eczema.
Electronic cigarette liquid
E422 Glycerol, along with propylene glycol, is a common component of e-liquid, a solution used with electronic vaporizers (electronic cigarettes).
This E422 Glycerol is heated with an atomizer (a heating coil often made of Kanthal wire), producing the aerosol that delivers nicotine to the user.
Antifreeze
Like ethylene glycol and propylene glycol, E422 Glycerol is a non-ionic kosmotrope that forms strong hydrogen bonds with water molecules, competing with water-water hydrogen bonds.
This interaction disrupts the formation of ice.
The minimum freezing point temperature is about −38 °C (−36 °F) corresponding to 70% glycerol in water.
E422 Glycerol was historically used as an anti-freeze for automotive applications before being replaced by ethylene glycol, which has a lower freezing point.
While the minimum freezing point of a glycerol-water mixture is higher than an ethylene glycol-water mixture, glycerol is not toxic and is being re-examined for use in automotive applications.
In the laboratory, E422 Glycerol is a common component of solvents for enzymatic reagents stored at temperatures below 0 °C (32 °F) due to the depression of the freezing temperature.
E422 Glycerol is also used as a cryoprotectant where the glycerol is dissolved in water to reduce damage by ice crystals to laboratory organisms that are stored in frozen solutions, such as fungi, bacteria, nematodes, and mammalian embryos.
Some organisms like the moor frog produce E422 Glycerol to survive freezing temperatures during hibernation.
Preparation
E422 Glycerol industrial production methods can be divided into two categories: method using natural oil as raw material with the resulting glycerol commonly known as natural glycerol; method using propylene as raw material with the resulting glycerol commonly known as synthetic glycerol.
1. Production of natural E422 Glycerol; before 1984, glycerol was all recovered from the by-products of soap manufacturing from grease of animals and plants.
Until now, natural grease is still the main raw material for the production of E422 Glycerol with about 42% of the natural glycerol being made from by-products and 58% being made from fatty acids.
Saponification of Oil in the soap Industry: The products in saponification reaction products are divided into two layers: the upper layer mainly contains fatty acid sodium salt (soap) and a small amount of glycerol, the lower layer is the waste lye, being the glycerol dilute solution containing salt and sodium hydroxide, generally containing 9-16% glycerol and 8-20% inorganic salt.
Grease reaction: the glycerol water obtained from the grease hydrolysis (also known as sweet water) contains higher glycerol content than soap waste, being about 14-20% with 0-0.2% inorganic salt.
In recent years, E422 Glycerol has been widely applied of continuous high-pressure hydrolysis method.
The reaction is free of catalyst and the obtained sweet water is generally free of inorganic acid, thus can be more easily purified than the waste lye.
For both the soap waste liquid and the glycerol water obtained from oil hydrolysis, the glycerol is not high, and they contain all kinds of impurities.
The production process of the natural glycerol includes purification, concentration to obtain crude glycerol, and refining process including crude glycerol distillation, decolorization and deodorization.
This process is described in detail in some books.
2. The production of synthetic glycerol: those various pathways for glycerol synthesis from propylene can be summarized into two categories, namely chlorination and oxidation.
Now the industry is still using propylene chlorination method and propylene non-periodic acetic acid oxidation method.
(1) Propylene chlorination method: this is the most important production method of synthesizing glycerol, including a total of four steps, namely high-temperature propylene chlorination, chlorophenol hypochlorification, dichloropropanol saponification and epichlorohydrin hydrolysis.
The production process of glycerol by epichlorohydrin hydrolysis is performed under 150 ° C and 1.37 MPa pressure of carbon dioxide in an aqueous solution of 10% hydroxide and 1% sodium carbonate.
This can produce a glycerol aqueous solution containing 5-20% glycerol and sodium chloride, followed by concentration, desalting and distillation to obtain the glycerol with the purity of over 98%.
(2) Method of propylene peracetic acid oxidation: propylene can interact with peracetic acid to generate propylene oxide with propylene oxide isomerization generating alkene to propanol.
The latter reacts with peracetic acid to produce glycidyl alcohol (i.e. glycidyl), and finally hydrolyzed to glycerol.
The production of peracetic acid does not require catalyst, acetaldehyde and oxygen gas phase oxidation. Under atmospheric pressure, 150-160 ℃ and the contact time of 24 s, the aldehyde has a conversion rate of 11% and the acetic acid has a selectivity of 83%.
The latter two steps of the reaction can continuously proceeded in a special structure of the reaction distillation column.
The raw material allyl alcohol and the ethyl acetate solution containing peracetic acid are sent to the column and the column is controlled at 60-70 ° C and 13-20 kPa.
The top of the column can be evaporated of ethyl acetate solvent and water.
This method is selective and has high yield, taking peracetic acid as oxidant.
E422 Glycerol doesn’t need catalyst, and the reaction speed is high, simplifying the process.
Production of 1t E422 Glycerol consumes 1.001 t allyl alcohol and 1.184 t peracetic acid with 0.947 t of acetic acid by-product.
At present, both the production of natural glycerol and synthetic E422 Glycerol accounts of almost 50%.
The propylene chlorination process accounts for about 80% of the total glycerol production. China's natural E422 Glycerol accounted for more than 90% of total output.
