Метилцеллюлоза

Химические свойства

Methyl cellulose is a water soluble, gel-like substance with no odor and no taste.

Использование

Methyl cellulose is used as a thickener and an emulsifier in various food and cosmetic products; as a gel in advanced cookery and as a lubricant. It is also involved in the treatment of constipation. It acts as a buffer additive in capillary electrophoresis to control electoosmotic flow for improved separations. In paper and textile industries, it is used as a sizing, thereby protecting the fibers from water or oil.

Подготовка

Prepared from wood pulp or cotton by treatment with alkali and methylation of alkali cellulose with methyl chloride.

Методы производства

Methylcellulose is prepared from wood pulp (cellulose) by treatment with alkali followed by methylation of the alkali cellulose with methyl chloride. The product is then purified and ground to powder form.

Общее описание

Odorless white or creamy white fibrous powder. Tasteless.

Реакции воздуха и воды

Methyl cellulose is hygroscopic. Swells in water to a viscous, colloidal solid. Slightly water soluble.

Профиль реактивности

Methyl cellulose is incompatible with strong oxidizing agents. Methyl cellulose is also incompatible with aminacrine HCl, chlorocresol, mercuric chloride, phenol resorcinol, tannic acid and silver nitrate.

Пожароопасность

Flash point data for Methyl cellulose are not available; however, Methyl cellulose is probably combustible.

Профиль безопасности

A poison by intraperitoneal route. When heated to decomposition it emits acrid smoke and irritating fumes.

хранилище

Methylcellulose powder is stable, although slightly hygroscopic. The bulk material should be stored in an airtight container in a cool, dry place.
Solutions of methylcellulose are stable to alkalis and dilute acids at pH 3–11, at room temperature. At pH less than 3, acid-catalyzed hydrolysis of the glucose–glucose linkages occurs and the viscosity of methylcellulose solutions is reduced.On heating, solution viscosity is reduced until gel formation occurs at approximately 50°C;
Methylcellulose solutions are liable to microbial spoilage and antimicrobial preservatives should therefore be used. Solutions may also be sterilized by autoclaving, although this process can decrease the viscosity of a solution.The change in viscosity after autoclaving is related to solution pH. Solutions at pH less than 4 had viscosities reduced by more than 20% subsequent to autoclaving.

Несовместимости

chlorocresol; mercuric chloride; phenol; resorcinol; tannic acid; silver nitrate; cetylpyridinium chloride; p-hydroxybenzoic acid; paminobenzoic acid; methylparaben; propylparaben; and butylparaben.
Salts of mineral acids (particularly polybasic acids), phenols, and tannins will coagulate solutions of methylcellulose, although this can be prevented by the addition of ethanol (95%) or glycol diacetate. Complexation of methylcellulose occurs with highly surface-active compounds such as tetracaine and dibutoline sulfate.
High concentrations of electrolytes increase the viscosity of methylcellulose mucilages owing to the ‘salting out’ of methylcellulose. With very high concentrations of electrolytes, the methylcellulose may be completely precipitated in the form of a discrete or continuous gel. Methylcellulose is incompatible with strong oxidizing agents.

Регуляторный статус

GRAS listed. Accepted as a food additive in the USA, Europe and Japan. Included in the FDA Inactive Ingredients Database (sublingual tablets; IM injections; intrasynovial injections; nasal preparations; ophthalmic preparations; oral capsules, oral suspensions, and oral tablets; topical and vaginal preparations). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.Reported in the EPA TSCA inventory.