Ethyl lactate

Chemical properties

Ethyl Lactate is a colorless liquid with a light ethereal, buttery odor. It miscible in water, alcohols, ketones , esters, hydrocarbons, ether and oil. The odor threshold is reported to be 0.89 mg/m3 and the odor nuisance threshold to be 65 mg/m3.

Occurrence

Ethyl lactate is reported to be found in apple, citrus fruits, pineapple, peas, sauerkraut, vinegar, bread, beer, grape brandy, rum, whisky, cider, sherry, wine, cocoa, banty beer, plum brandy and pear brandy. It has been approved by the US FDA for food use.

The Uses of Ethyl lactate

Ethyl lactate is used as a solvent for nitrocellulose, cellulose acetate, and many cellulose ethers and resins. It is also used in lacquers, paints, enamels, varnishes, stencil sheets, safety glass and flavoring. Ethyl lactate is furthermore used in some cosmetic formulations in soaps, detergents, creams and lotions with a maximum concentration of 0.2 %. In recent years it has been used as degreaser as a substitute for trichloroethylene.

Preparation

Ethyl lactate is produced by the esterification of lactic acid with ethanol in the presence of a little mineral oil, or by combination of acetaldehyde with hydrocyanic acid to form acetaldehyde cyanhydrin. This is followed by treatment with ethanol (95%) and hydrochloric or sulfuric acid. Purification is achieved using fractional distillation. The commercial product is a racemic mixture.

Definition

ChEBI: Ethyl 2-hydroxypropanoate is the ethyl ester obtained of 2-hydroxypropanoic acid. It has a role as a metabolite. It is a secondary alcohol, a lactate ester and an ethyl ester. It is functionally related to a 2-hydroxypropanoic acid.

Synthesis Reference(s)

Synthetic Communications, 19, p. 1335, 1989 DOI: 10.1080/00397918908054542

General Description

A clear colorless liquid with a mild odor. Flash point 115°F. Denser than water and soluble in water. Vapors heavier than air.

Air & Water Reactions

Flammable. Soluble in water.

Reactivity Profile

Ethyl lactate is an ester. Esters react with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing esters with alkali metals and hydrides.

Health Hazard

Inhalation of concentrated vapor may cause drowsiness. Contact with liquid causes mild irritation of eyes and (on prolonged contact) skin. Ingestion may cause narcosis.

Fire Hazard

HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.

Safety

Ethyl lactate is used as a flavoring agent in pharmaceutical preparations, and is found in food products. The estimated acceptable daily intake for lactic acid is 12.5 mg/kg body-weight.
In general, lactate esters have an oral LD50 > 2000 mg/kg; and the inhalation LC50 is generally above 5000 mg/m3. They have the potential of causing eye and skin irritation (on prolonged contact), but not sensitization. Ethyl lactate is moderately toxic by intraperitoneal, subcutaneous, and intravenous routes. There is low oral and skin contact toxicity; although ingestion may cause nausea, stomach and throat pain, and narcosis. Inhalation of concentrated vapor of ethyl lactate may cause irritation of the mucous membranes, drowsiness, and narcosis.
LD50 (rat, oral): >5.0 g/kg
LD50 (mouse, oral): 2.5 g/kg
LD50 (mouse, SC): 2.5 g/kg
LD50 (mouse, IV): 0.6 g/kg
LD50 (rabbit, skin): >5.0 g/kg

Veterinary Drugs and Treatments

Ethyl lactate shampoo can be used when an antibacterial shampoo (bacteriostatic and bactericidal) is needed particularly in animals with surface and superficial pyodermas that cannot tolerate benzoyl peroxide. It also has keratoplastic effect, which provides anti-seborrheic activity.
A lipid soluble compound, ethyl lactate penetrates hair follicles and sebaceous glands where bacterial lipases convert it into lactic acid and ethanol, which are responsible for its antibacterial action. It is not as active as benzoyl peroxide against staphylococcal organisms, but is less irritating and drying.

storage

Stable at normal temperature and pressure. Ethyl lactate is a flammable liquid and vapor. Store in a cool, dry, and well-ventilated location away from any fire hazard area, in a tightly closed container.

Incompatibilities

Incompatible with bases or strong alkalis and may cause fire or explosion with strong oxidizing agents.

Regulatory Status

GRAS listed. Reported in the EPA TSCA Inventory.