E1517 (GLYCERYL DIACETATE)

E1517 (Glyceryl Diacetate) is a synthetically produced food additive and industrial chemical classified as a diester of glycerol and acetic acid, used primarily as a carrier and solvent for flavourings, colorants, and other food additives in the European Union and as a plasticizer, humectant, and solvent in pharmaceutical, cosmetic, and industrial applications.
E1517 (Glyceryl Diacetate) is also known as diacetin and is produced by the esterification of glycerol with acetic acid or acetylating agents, yielding a clear, colorless to pale yellow, viscous, hygroscopic liquid that is miscible with water and ethanol and is metabolized in the body to the naturally occurring compounds glycerol and acetic acid.
E1517 (Glyceryl Diacetate) is typically a mixture of two positional isomers — 1,2-glyceryl diacetate (CAS 102-62-5) and 1,3-glyceryl diacetate (CAS 105-70-4) — along with minor amounts of monoacetin and triacetin, with the mixture identified by CAS number 25395-31-7.

CAS Number: 25395-31-7 (mixture); 102-62-5 (1,2-isomer); 105-70-4 (1,3-isomer)
EC Number (EINECS): 246-941-2
E Number: E1517
Molecular Formula: C7H12O5
Molecular Weight: 176.17 g/mol
IUPAC Name (1,2-isomer): (2-acetyloxy-3-hydroxypropyl) acetate; (1-acetyloxy-3-hydroxypropan-2-yl) acetate
IUPAC Name (1,3-isomer): (3-acetyloxy-2-hydroxypropyl) acetate
MDL Number: MFCD00008717
Beilstein Number: 1706903
PubChem CID: 66021 (1,2-isomer); 66924 (1,3-isomer)
ChemSpider: 59412 (1,2-isomer); 60286 (1,3-isomer)
ECHA InfoCard: 100.042.659
RTECS: AK3325000
FDA UNII: GJ0544W99Q (mixture); 9W955270ZW (1,2); G45CU3Z186 (1,3)
CompTox Dashboard (EPA): DTXSID5041223
HS Code: 2915.39.30 / 2917.19.70.50
WGK Germany: 1
Export Tariff Code: 2917.19.7050
Nikkaji: J5.009A

Synonyms: Diacetin, Glycerol diacetate, Glycerin diacetate, Glycerine diacetate, 1,2-Diacetylglycerol, Diacetylglycerol, Diacetyl glycerol, Diacetyl glycerine, Acetin di-, 1,2-Diacetin, 2,3-Diacetin, 2,3-Diacetoxypropan-1-ol, Glycerol 1,2-diacetate, Glycerol 1,3-di(acetate), Glyceryl 1,2-diacetate, 3-Hydroxypropane-1,2-diyl diacetate, 1,2,3-Propanetriol diacetate, 1,2,3-Propanetriol 1,2-diacetate, Acetic acid diglyceride, Estol 1582, HALLCO C-491, E1517

E1517 (Glyceryl Diacetate) is formed by the selective esterification of two of the three hydroxyl groups of the glycerol backbone with acetyl moieties, forming -O-C(=O)-CH3 ester linkages on the glycerol carbon chain; the 1,2-isomer is chiral (racemic in commercial form) while the 1,3-isomer is achiral.
E1517 (Glyceryl Diacetate) is closely related to monoacetin (E1516, glyceryl monoacetate) in which only one hydroxyl is acetylated, and to triacetin (E1518, glyceryl triacetate) in which all three hydroxyls are acetylated; these three compounds differ in physicochemical properties, water solubility, viscosity, and technological application.

E1517 (Glyceryl Diacetate) has been designated an acceptable daily intake (ADI) of "not specified" by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), indicating low toxicity concerns at typical use levels when used as a carrier solvent for food additives.
E1517 (Glyceryl Diacetate) is approved as a food additive in the European Union under Regulation (EC) No 1333/2008 under the quantum satis principle, meaning it may only be used in the quantity necessary to achieve the intended technological purpose, and is registered under REACH Regulation (EC) No 1907/2006 without classified hazards.

Uses of E1517 (Glyceryl Diacetate):
E1517 (Glyceryl Diacetate) is used in the food industry primarily as a carrier substance and solvent for fat-soluble and water-soluble flavourings, colorants, and other food additives, ensuring their uniform dissolution, dilution, and dispersion without altering their technological function.
E1517 (Glyceryl Diacetate) is used as a plasticizer and softening agent in edible coatings, casings, chewing gums, and bakery products, enhancing flexibility, texture, and stability of the product matrix.

E1517 (Glyceryl Diacetate) is used as a solvent in extraction processes during the manufacture of food additives, flavourings, and colorants, and as an auxiliary substance in the production of confectionery, baked goods, and beverages.
E1517 (Glyceryl Diacetate) is used as a humectant and solvent in pharmaceutical formulations including ointments, cough syrups, elixirs, expectorants, lozenges, topical preparations, and transdermal patches, facilitating drug penetration and controlled release.

E1517 (Glyceryl Diacetate) is used as a plasticizer in controlled-release systems such as push-pull osmotic pumps, providing smooth film surfaces that support consistent drug delivery, as demonstrated in gliclazide formulations.
E1517 (Glyceryl Diacetate) is used as a solvent, moisturizer, and emollient in cosmetic formulations including lotions, creams, mouthwashes, and toothpastes, where it softens skin, improves spreadability, and acts as a flavoring solvent.

E1517 (Glyceryl Diacetate) is used as a versatile plasticizer in industrial polymer applications for enhancing flexibility and processability of cellulose acetate films and resins, as incorporated into cellulose diacetate blends to improve tensile properties and biodegradability.
E1517 (Glyceryl Diacetate) is used as a co-solvent and oxygenated additive in biodiesel fuel formulations, where it forms as a byproduct of glycerol acetylation during biodiesel production, enhancing cold flow properties, lubricity, and cetane index while reducing emissions.

E1517 (Glyceryl Diacetate) is used as a humectant in tobacco processing to retain moisture and maintain leaf pliability and texture during manufacturing.
E1517 (Glyceryl Diacetate) is used as an indirect food additive in food contact substances such as cellophane under US FDA 21 CFR 177.1200, where it functions as a component in coatings and plasticizers.

Benefits or Advantages of E1517 (Glyceryl Diacetate):
E1517 (Glyceryl Diacetate) is metabolized in the body by enzymatic hydrolysis into glycerol and acetic acid — both naturally occurring metabolic intermediates — and is therefore considered safe for consumption with no known harmful effects when used within permitted levels.
E1517 (Glyceryl Diacetate) has no known allergenic potential, no demonstrated carcinogenic or mutagenic potential at permitted use levels, and good tolerability following oral ingestion, supported by an oral LD50 in mice of 8,500 mg/kg indicating very low acute toxicity.

E1517 (Glyceryl Diacetate) is miscible with water, ethanol, ether, and most organic solvents, providing exceptional solubility versatility for dissolving both hydrophilic and lipophilic flavourings, colorants, and active pharmaceutical ingredients.
E1517 (Glyceryl Diacetate) is compatible with all religious groups, vegetarians, and vegans, as it is a synthetically produced ester of glycerol and acetic acid derived without animal-derived raw materials.

E1517 (Glyceryl Diacetate) has a very high flash point greater than 110°C (>230°F) and a high boiling point of approximately 259–280°C, providing excellent thermal stability and low fire hazard during manufacturing and food processing operations.
E1517 (Glyceryl Diacetate) enhances the bioavailability of lipophilic drugs in pharmaceutical delivery systems by improving their solubility and absorption, as demonstrated in osmotic pump designs and transdermal patch formulations.

Features of E1517 (Glyceryl Diacetate):
E1517 (Glyceryl Diacetate) is a clear, colorless to pale yellow, viscous, hygroscopic, somewhat oily liquid at room temperature with a mild odor described as slightly alcoholic with faint fruity or buttery notes, and a mild oily buttery taste.
E1517 (Glyceryl Diacetate) is a mixture predominantly of the 1,2- and 1,3-diacetate isomers with minor amounts of monoacetin and triacetin byproducts; commercial assay is 95.00–100.00% (sum of isomers).

E1517 (Glyceryl Diacetate) has a very low vapor pressure of 0.007 mmHg at 25°C and a vapor density of 6.1 (air=1), indicating negligible volatility under normal conditions and minimal inhalation exposure risk during ambient handling.
E1517 (Glyceryl Diacetate) exhibits good chemical stability under neutral conditions (pH 5.5–7.5), with IR spectroscopy showing a characteristic carbonyl stretch at 1734 cm⁻¹ and C-O ester bands at 1217 cm⁻¹, and ¹H NMR acetate methyl protons at δ 2.06–2.09 ppm in CDCl₃.

Chemical Properties of E1517 (Glyceryl Diacetate):
E1517 (Glyceryl Diacetate) is a diester of glycerol (propane-1,2,3-triol) and acetic acid in which two of the three hydroxyl groups are esterified with acetyl groups (-OCOCH₃), with the molecular formula C₇H₁₂O₅ and molecular weight 176.17 g/mol.
E1517 (Glyceryl Diacetate) undergoes ester hydrolysis in the presence of water, acids, or bases, cleaving the acetate groups sequentially through monoacetin intermediates to regenerate glycerol and acetic acid; enzymatic hydrolysis by acetyl ester hydrolases is optimal at pH 6.7 and 40°C.

E1517 (Glyceryl Diacetate) is sensitive to strong acids, strong bases, and oxidizing agents which can accelerate hydrolysis or decomposition, and is hygroscopic and should be stored in sealed containers protected from moisture.
E1517 (Glyceryl Diacetate) has an octanol-water partition coefficient (logP) of approximately -0.30 to -0.64, reflecting moderate hydrophilicity, and a refractive index of n20/D 1.440.

Production of E1517 (Glyceryl Diacetate):
E1517 (Glyceryl Diacetate) is commercially produced by the esterification of glycerol with acetic acid in the presence of an acid catalyst such as sulfuric acid at elevated temperatures (100–120°C), producing a mixture of mono-, di-, and triacetins that are separated by vacuum distillation to yield the diacetin fraction at greater than 95% purity.
E1517 (Glyceryl Diacetate) is also produced by laboratory synthesis using acetic anhydride or acetyl chloride with glycerol at controlled molar ratios (1:2 glycerol:anhydride) and moderate temperatures (50–60°C) under acid or base catalysis, followed by purification by vacuum distillation or column chromatography.

E1517 (Glyceryl Diacetate) production increasingly uses green methods including immobilized lipases (e.g., Candida antarctica lipase B / Novozym 435) for enzymatic transesterification under mild conditions (40–60°C, solvent-free), and heterogeneous catalysts derived from biomass such as sulfonated mesoporous carbons, rice husk biosilica, and SnO₂-based catalysts.
E1517 (Glyceryl Diacetate) is also obtained as a byproduct intermediate in triacetin manufacturing and from glycerol surplus generated in biodiesel production, supporting its valorization through eco-friendly synthesis routes and circular economy principles.

Material Safety Data Sheet (MSDS) of E1517 (Glyceryl Diacetate):

Handling of E1517 (Glyceryl Diacetate):
E1517 (Glyceryl Diacetate) should be handled in accordance with good industrial hygiene and safety practices and in compliance with the applicable Safety Data Sheet.
E1517 (Glyceryl Diacetate) handling requires avoiding contact with skin and eyes (S24/25), keeping out of reach of children (S02), and using appropriate protective equipment including gloves and safety glasses.

SDS of E1517 (Glyceryl Diacetate):

Stability and Reactivity of E1517 (Glyceryl Diacetate):

Chemical stability:
E1517 (Glyceryl Diacetate) is stable under normal storage and handling conditions across pH 5.5–7.5.

Reactivity:
No dangerous reaction is expected under normal conditions of use.
E1517 (Glyceryl Diacetate) undergoes hydrolysis under concentrated acidic or alkaline conditions and may react with strong oxidizing agents.

Conditions to avoid:
Strong acids (concentrated).
Strong bases (concentrated).
Strong oxidizing agents.
Moisture and prolonged air exposure (hygroscopic).
High temperatures (risk of decomposition above flash point).

Incompatible materials:
Strong oxidizing agents.
Concentrated strong acids.
Concentrated strong alkalis.
Reactive acetylating agents.

Hazardous decomposition products:
Carbon monoxide (CO).
Carbon dioxide (CO2).
Acetic acid vapors (under thermal decomposition or fire conditions).
Irritating organic fumes.

Handling and Storage of E1517 (Glyceryl Diacetate):

Handling:
Handle in accordance with good industrial hygiene and safety practices.
Avoid contact with skin and eyes.
Keep out of reach of children.
Do not eat, drink, or smoke in handling areas.
Wash hands after handling.

Storage:
Store in sealed original containers in a cool, dry, well-ventilated area.
Protect E1517 (Glyceryl Diacetate) from excessive heat, direct sunlight, and moisture.
Keep away from strong oxidizing agents and incompatible chemicals.

First Aid Measures of E1517 (Glyceryl Diacetate):

Inhalation:
Move affected person to fresh air.
If respiratory irritation develops, seek medical advice.
Inhalation risk is minimal under normal conditions due to very low vapor pressure.

Skin contact:
Wash affected skin with soap and plenty of water.
E1517 (Glyceryl Diacetate) may be mildly irritating to skin upon prolonged direct contact; seek medical advice if irritation persists.

Eye contact:
Immediately rinse cautiously with clean water for at least 15 minutes while holding eyelids open.
Seek medical attention if irritation develops or persists.

Ingestion:
Rinse mouth with water.
Do not induce vomiting unless instructed by medical personnel.
Seek medical advice; oral toxicity is very low (oral LD50 mouse: 8,500 mg/kg).

Firefighting Measures of E1517 (Glyceryl Diacetate):

Suitable extinguishing media:
Water spray, foam, dry chemical powder, or carbon dioxide.

Specific hazards:
E1517 (Glyceryl Diacetate) is a combustible liquid with a flash point greater than 110°C (>230°F TCC); it is not readily ignitable under normal ambient conditions.
Thermal decomposition or combustion may produce carbon monoxide, carbon dioxide, acetic acid vapors, and irritating organic fumes.

Protective equipment for firefighters:
Wear self-contained breathing apparatus (SCBA) and full protective clothing.

Firefighting instructions:
Cool exposed containers with water spray.
Prevent contaminated firefighting water from entering drains or waterways.

Accidental Release Measures of E1517 (Glyceryl Diacetate):

Personal precautions:
Avoid contact with eyes and skin; spilled E1517 (Glyceryl Diacetate) creates a slipping hazard.
Use appropriate personal protective equipment.

Environmental precautions:
Prevent E1517 (Glyceryl Diacetate) from entering drains or waterways; it has no classified environmental hazards under REACH but should be handled responsibly.

Methods for cleaning up:
Contain spill with inert absorbent material such as sand or vermiculite.
Collect into properly labeled waste containers for disposal according to local regulations.
Wash contaminated surfaces with water after collection.

Exposure Controls / Personal Protective Equipment of E1517 (Glyceryl Diacetate):

Engineering controls:
Provide adequate ventilation under normal conditions.

Eye protection:
Wear safety glasses or chemical splash goggles where splashing is possible.

Hand protection:
Wear gloves for prolonged or repeated skin contact.

Respiratory protection:
Not normally required under ambient conditions given the very low vapor pressure of E1517 (Glyceryl Diacetate).

Hygiene measures:
Wash hands after handling E1517 (Glyceryl Diacetate) and before eating, drinking, or smoking.

Identifiers of E1517 (Glyceryl Diacetate):
E Number: E1517
CAS Number: 25395-31-7 (mixture); 102-62-5 (1,2-isomer); 105-70-4 (1,3-isomer)
EC Number: 246-941-2
Molecular Formula: C7H12O5
Molecular Weight: 176.17 g/mol
MDL Number: MFCD00008717
Beilstein: 1706903
PubChem CID: 66021 (1,2); 66924 (1,3)
RTECS: AK3325000
FDA UNII: GJ0544W99Q
CompTox (EPA): DTXSID5041223
HS Code: 29153930
WGK Germany: 1
GHS Classification: None found (not classified as hazardous)
GHS Hazard Statements: None
GHS Precautionary: None (S24/25 — avoid skin and eye contact; S02 — keep out of reach of children)
JECFA ADI: Not specified
EU Status: Approved food additive (E1517) under Regulation (EC) No 1333/2008
US FDA: Indirect food additive (21 CFR 177.1200); GRAS for certain food uses
REACH: Registered; no classified hazards
TSCA: Listed
Cosmetics (EU): Permitted solvent under Regulation (EC) No 1223/2009
Dietary restrictions: Suitable for all religious groups, vegetarians, and vegans
Isomer class: Diglyceride (diester of glycerol and acetic acid)

Properties of E1517 (Glyceryl Diacetate):
Physical state (25°C): Liquid
Appearance: Clear, colorless to pale yellow viscous hygroscopic oily liquid
Odor: Mild; slightly alcoholic with faint fruity/buttery notes (odor strength: very mild)
Taste: Mild, oily, buttery
Melting point: -30°C
Boiling point: 245–280°C (at 760 mmHg)
Flash point: >110°C (>230°F, TCC)
Density (25°C): 1.17–1.1875 g/cm³
Specific gravity (25°C): 1.17–1.195
Refractive index: n20/D 1.440
Viscosity (dynamic, 25°C): ~35.7 cP
Vapor pressure (25°C): 0.007 mmHg
Vapor density (air=1): 6.1
Solubility in water: Fully miscible (estimated 657,700 mg/L at 25°C)
Solubility in organic solvents: Miscible with ethanol, ether, benzene, and most organic solvents
logP (octanol/water): -0.30 to -0.64
Hygroscopic: Yes
IR carbonyl stretch: 1734 cm⁻¹
¹H NMR (CDCl₃): δ 2.06–2.09 ppm (acetate methyl)
Assay (commercial): 95–100% (sum of isomers)

Specifications of E1517 (Glyceryl Diacetate):
Chemical name: Glyceryl diacetate (Diacetin)
CAS Number: 25395-31-7 (mixture)
Molecular formula: C7H12O5
Molecular weight: 176.17 g/mol
Assay: 95.00–100.00% (sum of 1,2- and 1,3-isomers)
Appearance: Colorless to pale yellow clear oily liquid
Specific gravity (25°C): 1.170–1.195
Refractive index (20°C): 1.184–1.187
Boiling point: 245–280°C at 760 mmHg
Flash point: >110°C (closed cup)
Vapor pressure (25°C): 0.007 mmHg
Solubility: Miscible with water and ethanol
logP: -0.30 to -0.64
Storage: Sealed container, cool dry place, protected from moisture and heat

Names of E1517 (Glyceryl Diacetate):
E1517
Glyceryl Diacetate
Diacetin
Glycerol Diacetate
Glycerin Diacetate
Glycerine Diacetate
1,2-Diacetylglycerol
Diacetylglycerol
Diacetyl Glycerol
Diacetyl Glycerine
Acetin Di-
1,2-Diacetin
2,3-Diacetin
2,3-Diacetoxypropan-1-ol
Glycerol 1,2-Diacetate
Glycerol 1,3-Di(acetate)
Glyceryl 1,2-Diacetate
3-Hydroxypropane-1,2-diyl Diacetate
1,2,3-Propanetriol Diacetate
1,2,3-Propanetriol 1,2-Diacetate
Acetic Acid Diglyceride
Estol 1582
HALLCO C-491
CAS 25395-31-7