METHOD OF PRODUCING METHYLHYDROXYPROPYL CELLULOSE, WHICH FORMS AQUEOUS SOLUTIONS OF DIFFERENT VISCOSITY Russian patent published in 2024 - IPC C08B11/193 

FIELD: cellulose production; chemistry.

SUBSTANCE: invention relates to a method of producing methylhydroxypropyl cellulose, which forms aqueous solutions of different viscosity. Method involves preparation of a heterogeneous reaction mixture from native cellulose, propylene oxide, methyl chloride, an aqueous solution of sodium hydroxide and an auxiliary substance, which are mixed in an autoclave. Method is characterized by the fact that it involves the following sequence of actions: a) cellulose is introduced into the autoclave and evacuated; b) adding an alkylating – hydroxyalkylating cross-linking mixture of methyl chloride, propylene oxide and an auxiliary substance; c) 50% sodium hydroxide solution is sprayed onto the intensively stirred reaction mixture; d) the mixture in the reactor is slowly heated to 75–90 °C and continues to be intensively mixed for 1.5–2.5 hours; e) fast cooling of external walls of reactor by running cold water; f) mixture is neutralized with acid to pH=7–8; g) at least 5 times the mixture is washed with hot water with intermediate squeezing and hydrophilization at the last washing step; h) drying the reaction product at temperature of 90–110 °C to constant weight; i) the reaction product is ground and sieved through a sieve with mesh size of at least 0.5 mm.

EFFECT: obtaining low-cost water-soluble MHPC, easily dispersible and quickly dissolving in water with formation of viscous gel-like solutions of various viscosity (1% solution, viscosity from 50 to 78,000 cP).

10 cl, 1 tbl