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Ethyl cellulose is a derivative of cellulose in which some of the hydroxyl groups on the repeating glucose units are converted into ethyl ether groups.
The number of ethyl groups can vary depending on the manufacturer.
Ethyl cellulose is mainly used as a thin-film coating material for coating paper, vitamin and medical pills, and for thickeners in cosmetics and in industrial processes.
CAS: 9004-57-3
MF: C23H24N6O4
MW: 448.47446
EINECS: 618-384-9
Synonyms
ampacete/c;aquacoat;aquacoatecd30;aquacoatecd30fmc;cellulose,triethylether;celluloseethyl;nixone/c;spt50cps
Food grade ethyl cellulose is one of few non-toxic films and thickeners which are not water-soluble.
This property allows Ethyl cellulose to be used to safeguard ingredients from water.
Ethyl cellulose is also used as a food additive as an emulsifier (E462).
Ethyl cellulose is commonly used as a coating material for tablets and capsules, as it provides a protective barrier that prevents the active ingredients from being released too quickly in the digestive system.
Ethyl cellulose is also used as a binder, thickener, and stabilizer in a variety of food, cosmetic, and pharmaceutical products.
Ethyl cellulose is a tasteless, free-flowing, white to light tan-colored powder.
Ethyl cellulose is a glycoside.
Ethyl cellulose Chemical Properties
Melting point: 240-255 °C
density: 1.14 g/mL at 25 °C (lit.)
refractive index: n20/D 1.47(lit.)
storage temp.: 2-8°C
solubility: esters, aromatic hydrocarbons, alcohols and ketones: soluble
form: powder
Specific Gravity: 1.14
color: White to slightly yellow
Water Solubility: insoluble
Thermal Conductivity: 0.23 W/(m·K)
Merck: 14,3781
Dielectric constant: 2.8（Ambient）
Cosmetics Ingredients Functions: VISCOSITY CONTROLLING
BINDING
FILM FORMING
Cosmetic Ingredient Review (CIR): Ethyl cellulose (9004-57-3)
InChI: InChI=1S/C23H24N6O4/c1-4-5-8-28(9-10-33-17(3)30)20-6-7-22(16(2)11-20)26-27-23-18(14-24)12-21(29(31)32)13-19(23)15-25/h6-7,11-13H,4-5,8-10H2,1-3H3/b27-26+
InChIKey: ARSKJXYLLONUAJ-CYYJNZCTSA-N
EPA Substance Registry System: Ethyl cellulose (9004-57-3)
Ethyl celluloses are low density polymers (1070–1180 kg.m–3) with solubilities depending on the degree of ethylation; usually commercial grade contains 44–48% ethoxyl functional groups.
Solid masses of ethylcellulose exhibit low absorption of moisture, excellent dimensional stability and low temperature toughness and impact resistance.
Chemically they are less resistant towards acids than cellulose esters but much more resistant to alkalis.
They can be processed by injection molding.
Because ethyl cellulose is soluble in a wide variety of solvents, it provides a wide variety of varnish formulations.
Benzylcelluloses yield plastics with excellent dielectric properties and chemical stability.
Uses
In the manufacture of plastics and lacquers.
Pharmaceutic aid (tablet binder).
Used as a binder and filler in dry vitamin preparations, as a component of protective coatings for vitamin and mineral tablets, and as a fixative in flavoring compounds.
Ethyl cellulose is a cellulose ether containing ethyoxy groups attached by an ether linkage and containing an anhydrous basis of not more than 2.6 ethoxy groups per anhydroglucose unit.
Film-former in coatings, hot-melt adhesives and transfer inks and as a plastic coating for a variety of substrates.
ethyl cellulose is a binder, film former, and thickener.
Ethyl cellulose is used in suntan gels, creams, and lotions.
This is the ethyl ether of cellulose.
Pharmaceutical Applications
Ethyl cellulose is widely used in oral and topical pharmaceutical formulations.
The main use of ethylcellulose in oral formulations is as a hydrophobic coating agent for tablets and granules.
Ethylcellulose coatings are used to modify the release of a drug, to mask an unpleasant taste, or to improve the stability of a formulation; for example, where granules are coated with ethyl cellulose to inhibit oxidation.
Modified-release tablet formulations may also be produced using ethylcellulose as a matrix former.
Ethylcellulose, dissolved in an organic solvent or solvent mixture, can be used on its own to produce water-insoluble films. Higher-viscosity ethylcellulose grades tend to produce stronger and more durable films.
Ethylcellulose films may be modified to alter their solubility, by the addition of hypromellose or a plasticizer.
An aqueous polymer dispersion (or latex) of ethyl cellulose such as Aquacoat ECD (FMC Biopolymer) or Surelease (Colorcon) may also be used to produce ethylcellulose films without the need for organic solvents.
Drug release through ethyl cellulose-coated dosage forms can be controlled by diffusion through the film coating.
This can be a slow process unless a large surface area (e.g. pellets or granules compared with tablets) is utilized.
In those instances, aqueous ethyl cellulose dispersions are generally used to coat granules or pellets.
Ethyl cellulose-coated beads and granules have also demonstrated the ability to absorb pressure and hence protect the coating from fracture during compression.
High-viscosity grades of ethylcellulose are used in drug microencapsulation.
Release of a drug from an ethyl cellulose microcapsule is a function of the microcapsule wall thickness and surface area.
In tablet formulations, ethyl cellulose may additionally be employed as a binder, the ethyl cellulose being blended dry or wetgranulated with a solvent such as ethanol (95%). Ethyl cellulose produces hard tablets with low friability, although they may demonstrate poor dissolution.
Ethyl cellulose has also been used as an agent for delivering therapeutic agents from oral (e.g. dental) appliances.
In topical formulations, ethyl cellulose is used as a thickening agent in creams, lotions, or gels, provided an appropriate solvent is used.
Ethyl cellulose has been studied as a stabilizer for emulsions.
Ethyl cellulose is additionally used in cosmetics and food products.
Production Methods
Ethyl cellulose is prepared by treating purified cellulose (sourced from chemical-grade cotton linters and wood pulp) with an alkaline solution, followed by ethylation of the alkali cellulose with chloroethane as shown below, where R represents the cellulose radical:
RONa + C2H5Cl→ROC2H5+NaCl
The manner in which the ethyl group is added to cellulose can be described by the degree of substitution (DS).
The DS designates the average number of hydroxyl positions on the anhydroglucose unit that have been reacted with ethyl chloride.
Since each anhydroglucose unit of the cellulose molecule has three hydroxyl groups, the maximum value for DS is three.
Preparation
Ethyl cellulose is prepared by reacting cellulose with caustic to form caustic cellulose, which is then reacted with chloroethane to form ethyl cellulose.
Plasticgrade material contains 44-48% ethoxyl.
Although not as resistant as cellulose esters to acids, it is much more resistant to bases.
An outstanding feature is its toughness at low temperatures.
