Abstract: There is provided a method for producing a depolymerized cellulose ether having yellowness reduced. More specifically, there is provided a method for producing a depolymerized cellulose ether comprising a depolymerization step of depolymerizing a cellulose ether with an aqueous solution of acid in the presence of a polyhydric alcohol having 2 to 6 carbon atoms.

Abstract: There is provided a method for producing hydroxypropyl methyl cellulose phthalate (HPMCP), including an esterification step of reacting hydroxypropyl methyl cellulose with a carboxybenzoylating agent in the presence of an aliphatic carboxylic acid in a kneader reactor equipped with two or more stirring blades rotating around their own axes and orbitally revolving, to obtain a reaction product solution containing HPMCP; a precipitation step of precipitating the HPMCP by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCP; and a washing and recovery step of washing the HPMCP in the suspension and recovering the washed HPMCP. Further, there is provided HPMCP having yellowness at 20° C. of 10.0 or less, as determined in a 10% by mass solution of the HPMCP in acetone.

Abstract: There is provided a method for efficiently produce hydroxypropyl methyl cellulose acetate succinate (HPMCAS) having excellent flowability, where acetic acid in a reaction product mixture subjected to a wash and recovery step can be reduced. More specifically, there is provided a method for producing HPMCAS including an esterification step of esterifying hydroxypropyl methyl cellulose (HPMC) with acetic anhydride and succinic anhydride in acetic acid as a solvent to obtain a reaction product solution containing HPMCAS; a water addition step of adding water to the reaction product solution to obtain a water-added reaction product solution; an acetic acid removal step of removing at least a portion of both the solvent acetic acid and acetic acid derived from the acetic anhydride from the water-added reaction product solution to obtain a mixture having an acetic acid content reduced; and a wash and recovery step of washing the mixture and recovering the HPMCAS.

Abstract: There is provided a method for efficiently produce hydroxypropyl methyl cellulose acetate succinate (HPMCAS) having excellent flowability, where acetic acid in a reaction product mixture subjected to a wash and recovery step can be reduced. More specifically, there is provided a method for producing HPMCAS including an esterification step of esterifying hydroxypropyl methyl cellulose (HPMC) with acetic anhydride and succinic anhydride in acetic acid as a solvent to obtain a reaction product solution containing HPMCAS; a water addition step of adding water to the reaction product solution to obtain a water-added reaction product solution; an acetic acid removal step of removing at least a portion of both the solvent acetic acid and acetic acid derived from the acetic anhydride from the water-added reaction product solution to obtain a mixture having an acetic acid content reduced; and a wash and recovery step of washing the mixture and recovering the HPMCAS.

Abstract: There is provided a method for producing hydroxypropyl methyl cellulose acetate succinate (HPMCAS), including an esterification step of reacting hydroxypropyl methyl cellulose with an acetylating agent and a succinoylating agent in the presence of an aliphatic carboxylic acid in a kneader reactor equipped with two or more stirring blades rotating around their own axes and orbitally revolving, to obtain a reaction product solution containing HPMCAS; a precipitation step of precipitating the HPMCAS by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCAS; and a washing and recovery step of washing the HPMCAS in the suspension and recovering the washed HPMCAS. Further, there is provided HPMCAS having yellowness at 20° C. of 15.0 or less, as determined in a 2% by mass solution of the HPMCAS in a mixed solvent of dichloromethane, methanol and water in a mass ratio of 44:44:10.

Abstract: There is provided a method for producing hypromellose acetate succinate (HPMCAS), the method not requiring any special device and facilitating removal of impurities. More specifically, there is provided a method for producing HPMCAS, including an esterification step of esterifying hypromellose with an acetylating agent and a succinoylating agent in the presence of an aliphatic carboxylic acid to obtain a reaction product solution containing HPMCAS; a precipitation step of precipitating the HPMCAS by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCAS; a neutralization step of neutralizing the suspension with a basic substance to obtain a neutralized suspension; and a washing step of washing the HPMCAS contained in the neutralized suspension to obtain the washed HPMCAS.

Abstract: There is provided a method for producing hypromellose phthalate (HPMCP), the method not requiring any special device, and facilitating removal of impurities. More specifically, there is provided a method for producing HPMCP, including an esterification step of esterifying hypromellose with a carboxybenzoylating agent in the presence of an aliphatic carboxylic acid to obtain a reaction product solution containing HPMCP; a precipitation step of precipitating the HPMCP by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCP; a neutralization step of neutralizing the suspension with a basic substance to obtain a neutralized suspension; and a washing step of washing the HPMCP contained in the neutralized suspension to obtain the washed HPMCP.

Abstract: There is provided a method for producing a depolymerized cellulose ether having yellowness reduced. More specifically, there is provided a method for producing a depolymerized cellulose ether comprising a depolymerization step of depolymerizing a cellulose ether with an aqueous solution of acid in the presence of a polyhydric alcohol having 2 to 6 carbon atoms.

Abstract: There is provided a method for efficiently produce hydroxypropyl methyl cellulose acetate succinate (HPMCAS) having excellent flowability, where acetic acid in a reaction product mixture subjected to a wash and recovery step can be reduced. More specifically, there is provided a method for producing HPMCAS including an esterification step of esterifying hydroxypropyl methyl cellulose (HPMC) with acetic anhydride and succinic anhydride in acetic acid as a solvent to obtain a reaction product solution containing HPMCAS; a water addition step of adding water to the reaction product solution to obtain a water-added reaction product solution; an acetic acid removal step of removing at least a portion of both the solvent acetic acid and acetic acid derived from the acetic anhydride from the water-added reaction product solution to obtain a mixture having an acetic acid content reduced; and a wash and recovery step of washing the mixture and recovering the HPMCAS.

Abstract: There is provided a method for efficiently produce hydroxypropyl methyl cellulose phthalate (HPMCP) having excellent flowability, where acetic acid in a reaction product mixture subjected to a wash and recovery step can be reduced. More specifically, there is provided a method for producing HPMCP including an esterification step of esterifying hydroxypropyl methyl cellulose (HPMC) with phthalic anhydride in acetic acid as a solvent to obtain a reaction product solution containing HPMCP; a water addition step of adding water to the reaction product solution to obtain a water-added reaction product solution; an acetic acid removal step of removing at least a portion of the acetic acid from the water-added reaction product solution to obtain a mixture having an acetic acid content reduced; and a wash and recovery step of washing the mixture and recovering the HPMCP.

Abstract: There is provided a method for producing hydroxypropyl methyl cellulose phthalate (HPMCP), including an esterification step of reacting hydroxypropyl methyl cellulose with a carboxybenzoylating agent in the presence of an aliphatic carboxylic acid in a kneader reactor equipped with two or more stirring blades rotating around their own axes and orbitally revolving, to obtain a reaction product solution containing HPMCP; a precipitation step of precipitating the HPMCP by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCP; and a washing and recovery step of washing the HPMCP in the suspension and recovering the washed HPMCP. Further, there is provided HPMCP having yellowness at 20° C. of 10.0 or less, as determined in a 10% by mass solution of the HPMCP in acetone.

Abstract: There is provided a method for producing hydroxypropyl methyl cellulose acetate succinate (HPMCAS), including an esterification step of reacting hydroxypropyl methyl cellulose with an acetylating agent and a succinoylating agent in the presence of an aliphatic carboxylic acid in a kneader reactor equipped with two or more stirring blades rotating around their own axes and orbitally revolving, to obtain a reaction product solution containing HPMCAS; a precipitation step of precipitating the HPMCAS by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCAS; and a washing and recovery step of washing the HPMCAS in the suspension and recovering the washed HPMCAS. Further, there is provided HPMCAS having yellowness at 20° C. of 15.0 or less, as determined in a 2% by mass solution of the HPMCAS in a mixed solvent of dichloromethane, methanol and water in a mass ratio of 44:44:10.

Abstract: There is provided a method for producing a low polymerization degree cellulose ether having a less yellowish appearance and having excellent long-term storage stability through depolymerization of a high polymerization degree cellulose ether with an acid and without requiring an additive other than the acid. More specifically, there is provided a method for producing a low polymerization degree cellulose ether, including a step of depolymerizing a high polymerization degree cellulose ether with an acid to obtain a low polymerization degree cellulose ether mixture and a step of neutralizing the acid present in the low polymerization degree cellulose ether mixture, wherein ultraviolet is applied in the step of depolymerizing or between the steps of depolymerizing and neutralizing.

Abstract: There is provided is a hydroxyalkyl alkyl cellulose exhibiting good flowability and high compressibility. More specifically, provided are a hydroxyalkyl alkyl cellulose having a volume-based average particle diameter, determined by dry laser diffractometry, of 50 to 100 ?m, and having, on a basis of a dynamic image analysis to divide all particles into fine particles, spherical particles and fibrous particles, a volume fraction of the fibrous particles consisting of long and short fibrous particles relative to all of the particles of 45 to 70%, and a volume fraction of the fine particles relative to all of the particles of less than 2.0%; a solid preparation including the hydroxyalkyl alkyl cellulose; and others.

Abstract: There is provided a method for producing hypromellose acetate succinate (HPMCAS), the method not requiring any special device and facilitating removal of impurities. More specifically, there is provided a method for producing HPMCAS, including an esterification step of esterifying hypromellose with an acetylating agent and a succinoylating agent in the presence of an aliphatic carboxylic acid to obtain a reaction product solution containing HPMCAS; a precipitation step of precipitating the HPMCAS by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCAS; a neutralization step of neutralizing the suspension with a basic substance to obtain a neutralized suspension; and a washing step of washing the HPMCAS contained in the neutralized suspension to obtain the washed HPMCAS.

Abstract: There is provided a method for producing hypromellose phthalate (HPMCP), the method not requiring any special device, and facilitating removal of impurities. More specifically, there is provided a method for producing HPMCP, including an esterification step of esterifying hypromellose with a carboxybenzoylating agent in the presence of an aliphatic carboxylic acid to obtain a reaction product solution containing HPMCP; a precipitation step of precipitating the HPMCP by mixing the reaction product solution with water to obtain a suspension of the precipitated HPMCP; a neutralization step of neutralizing the suspension with a basic substance to obtain a neutralized suspension; and a washing step of washing the HPMCP contained in the neutralized suspension to obtain the washed HPMCP.

Abstract: Provided is a hydroxyalkyl alkyl cellulose exhibiting good flowability and high compressibility. More specifically, there are provided a hydroxyalkyl alkyl cellulose having a volume-based average particle size, determined by dry laser diffractometry, of more than 100 ?m and not more than 150 ?m; and after dividing all particles into fine particles, spherical particles and fibrous particles by a dynamic image analysis, a volume fraction of the fibrous particles relative to all of the particles of more than 40% and not more than 50%, and a volume fraction of the fine particles relative to all of the particles of less than 2.0%; a solid preparation including the hydroxyalkyl alkyl cellulose; and others.

Abstract: Provided is a hydroxyalkyl alkyl cellulose exhibiting good flowability and high compressibility. More specifically, there are provided a hydroxyalkyl alkyl cellulose having a volume-based average particle size, determined by dry laser diffractometry, of more than 100 ?m and not more than 150 ?m; and after dividing all particles into fine particles, spherical particles and fibrous particles by a dynamic image analysis, a volume fraction of the fibrous particles relative to all of the particles of more than 40% and not more than 50%, and a volume fraction of the fine particles relative to all of the particles of less than 2.0%; a solid preparation including the hydroxyalkyl alkyl cellulose; and others.

Abstract: There is provided is a hydroxyalkyl alkyl cellulose exhibiting good flowability and high compressibility. More specifically, provided are a hydroxyalkyl alkyl cellulose having a volume-based average particle diameter, determined by dry laser diffractometry, of 50 to 100 ?m, and having, on a basis of a dynamic image analysis to divide all particles into fine particles, spherical particles and fibrous particles, a volume fraction of the fibrous particles consisting of long and short fibrous particles relative to all of the particles of 45 to 70%, and a volume fraction of the fine particles relative to all of the particles of less than 2.0%; a solid preparation including the hydroxyalkyl alkyl cellulose; and others.

Abstract: There is provided a method for producing a low polymerization degree cellulose ether having a less yellowish appearance and having excellent long-term storage stability through depolymerization of a high polymerization degree cellulose ether with an acid and without requiring an additive other than the acid. More specifically, there is provided a method for producing a low polymerization degree cellulose ether, including a step of depolymerizing a high polymerization degree cellulose ether with an acid to obtain a low polymerization degree cellulose ether mixture and a step of neutralizing the acid present in the low polymerization degree cellulose ether mixture, wherein ultraviolet is applied in the step of depolymerizing or between the steps of depolymerizing and neutralizing.