Abstract: A process for producing a crosslinked cellulose ether including the steps of (i) contacting at least one cellulose material with a mixture comprising (ia) at least one crosslinking agent and (ib) at least one alkalization reagent to form an activated cellulose material; and (ii) contacting the activated cellulose material of step (i) with at least one etherification reagent; wherein the at least one etherification reagent reacts with the activated cellulose material to form the crosslinked cellulose ether; and a crosslinked cellulose ether produced by the above process.

Abstract: A process for fractionating an esterified cellulose ether comprising groups of the formula —C(O)—R—COOH, wherein R is a divalent hydrocarbon group, comprises the steps of a) blending the esterified cellulose ether comprising groups of the formula —C(O)—R—COOH with an aqueous liquid and setting the temperature of the resulting blend to less than 10° C. to dissolve a portion of the esterified cellulose ether in the aqueous liquid, b) separating the non-dissolved portion of the esterified cellulose ether from the remainder of the blend, and c) recovering or disposing of the esterified cellulose ether that is dissolved in the aqueous liquid.

Abstract: A process for recovering an esterified cellulose ether from a reaction product mixture obtained from a reaction of (a) a cellulose ether with (b) an aliphatic monocarboxylic acid anhydride or a di- or tricarboxylic acid anhydride or a combination of an aliphatic monocarboxylic acid anhydride and a di- or tricarboxylic acid anhydride, comprises the steps of (i) contacting the reaction product mixture with an aqueous liquid and precipitating the esterified cellulose ether from the reaction product mixture, and (ii) isolating the precipitated esterified cellulose ether from the mixture obtained in step (i), Tackiness of the esterified cellulose ether can be reduced when before or in step (i) a particulate silicon oxide or metal oxide is dispersed or suspended in the reaction product mixture, the aqueous liquid or a combination thereof.

Abstract: A process for recovering an esterified cellulose ether from a reaction product mixture obtained from a reaction of (a) a cellulose ether with (b) an aliphatic monocarboxylic acid anhydride or a di- or tricarboxylic acid anhydride or a combination of an aliphatic monocarboxylic acid anhydride and a di- or tricarboxylic acid anhydride, comprises the steps of (i) contacting the reaction product mixture with an aqueous liquid and precipitating the esterified cellulose ether from the reaction product mixture, and (ii) isolating the precipitated esterified cellulose ether from the mixture obtained in step (i), Tackiness of the esterified cellulose ether can be reduced when before or in step (i) a particulate silicon oxide or metal oxide is dispersed or suspended in the reaction product mixture, the aqueous liquid or a combination thereof.

Abstract: Esterified cellulose ethers which have i) as ester groups aliphatic monovalent acyl groups or a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, ii) a weight average molecular weight Mw of from 80,000 Dalton to 220,000 Dalton, iii) a Polydispersity Mw/Mn of from 1.3 to 4.0, and iv) an Mz/Mn of not more than 18.5, when the weight average molecular weight Mw, the number average molecular weight Mn and the z-average molecular weight Mz are measured by SEC-MALLS using as mobile phase a mixture produced from 40 parts by volume of acetonitrile and 60 parts by volume of aqueous buffer containing 50 mM NaH2—PO4 and 0.1 M NaNO3. are useful as enteric polymers for pharmaceutical dosage forms.

Abstract: In a process for preparing an esterified cellulose ether a cellulose ether is esterified with (i) an aliphatic monocarboxylic acid anhydride or (ii) a dicarboxylic acid anhydride or (iii) a combination of an aliphatic monocarboxylic acid anhydride and a dicarboxylic acid anhydride in the presence of an alkali metal carboxylate and an aliphatic carboxylic acid, wherein the molar ratio [alkali metal carboxylate/anhydroglucose units of cellulose ether] is not more than [1.20/1] and the molar ratio [aliphatic carboxylic acid/anhydroglucose units of cellulose ether] is from [3.55/1] to [9.0/1].

Abstract: Esterified cellulose ethers which have i) as ester groups aliphatic monovalent acyl groups or groups of the formula —C(O)—R—COOA or a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, and ii) a content of not more than 0.85 weight percent acetone-insoluble esterified cellulose ether particles, when the esterified cellulose ether is present in a mixture of 12.5 weight parts of esterified cellulose ether and 87.5 weight parts of acetone at 21° C., the weight percent acetone-insoluble esterified cellulose ether particles being based on the total weight of the esterified cellulose ether, wherein iii) not more than 14 percent of the acetone-insoluble esterified cellulose ether particles have a particle size of more than 90 micrometers.

Abstract: A process for making esterified cellulose ethers which have i) a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, ii) a weight average molecular weight Mw of from 80,000 Dalton to 350,000 Dalton, iii) a Polydispersity Mw/Mn of from 1.3 to 4.1, and iv) a viscosity of up to 4.0 mPa·s, measured as a 2.0 wt % solution of the esterified cellulose ether in 0.43 wt % aqueous NaOH at 20° C., are useful as enteric polymers for pharmaceutical dosage forms.

Abstract: A process for producing an esterified cellulose ether can be efficiently be produced by reacting a moist cellulose ether having a water content of at least 10 percent, based on the weight of the moist cellulose ether, with an aliphatic monocarboxylic acid anhydride, a dicarboxylic acid anhydride or a combination thereof. Further improvements in efficiency and reduction in process steps are achieved in a process for producing an esterified cellulose ether which comprises the steps of a) reacting cellulose with an alkaline material to produce alkali cellulose, b) reacting the produced alkali cellulose with one or more etherifying agents and washing the produced cellulose ether to obtain a moist cellulose ether having a water content of at least 10 weight percent, and c) reacting the moist cellulose ether with an aliphatic monocarboxylic acid anhydride and/or a dicarboxylic acid anhydride and with a depolymerizing agent.

Abstract: Esterified cellulose ethers which comprise (i) aliphatic monovalent acyl groups or (ii) groups of the formula —C(O)—R—COOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, or (iii) a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, which have a viscosity of up 19 mPa·s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20° C. and which have a weight average molecular weight Mw of at least 90,000 Dalton, are useful for preparing solid dispersions comprising drugs.

Abstract: Esterified cellulose ethers which comprise (i) groups of the formula —C(O)—R—COOA or (ii) a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, which have a viscosity of up 50 mPa·s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20° C., and a weight average molecular weight Mw of at least 220,000 Dalton, or which have a viscosity of up 100 mPa·s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20° C., and a weight average molecular weight Mw of at least 310,000 Dalton are useful for preparing solid dispersions comprising drugs.

Abstract: Esterified cellulose ethers which comprise (i) groups of the formula —C(O)—R—COOA or (ii) a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, which have a viscosity of up 50 mPa·s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20° C., and a weight average molecular weight Mw of at least 220,000 Dalton, or which have a viscosity of up 100 mPa·s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20° C., and a weight average molecular weight Mw of at least 310,000 Dalton are useful for preparing solid dispersions comprising drugs.

Abstract: A process for fractionating an esterified cellulose ether comprising groups of the formula —C(O)—R—COOH, wherein R is a divalent hydrocarbon group, comprises the steps of a) blending the esterified cellulose ether comprising groups of the formula —C(O)—R—COOH with an aqueous liquid and setting the temperature of the resulting blend to less than 10° C. to dissolve a portion of the esterified cellulose ether in the aqueous liquid, b) separating the non-dissolved portion of the esterified cellulose ether from the remainder of the blend, and c) recovering or disposing of the esterified cellulose ether that is dissolved in the aqueous liquid.

Abstract: A process for producing an esterified cellulose ether can be efficiently be produced by reacting a moist cellulose ether having a water content of at least 10 percent, based on the weight of the moist cellulose ether, with an aliphatic monocarboxylic acid anhydride, a dicarboxylic acid anhydride or a combination thereof. Further improvements in efficiency and reduction in process steps are achieved in a process for producing an esterified cellulose ether which comprises the steps of a) reacting cellulose with an alkaline material to produce alkali cellulose, b) reacting the produced alkali cellulose with one or more etherifying agents and washing the produced cellulose ether to obtain a moist cellulose ether having a water content of at least 10 weight percent, and c) reacting the moist cellulose ether with an aliphatic monocarboxylic acid anhydride and/or a dicarboxylic acid anhydride and with a depolymerizing agent.

Abstract: A process for producing an esterified cellulose ether comprises the step of reacting a cellulose ether with an aliphatic monocarboxylic acid anhydride and/or a dicarboxylic acid anhydride and with a depolymerizing agent, wherein the cellulose ether has an initial viscosity of at least 500 mPa·s, measured as a 2 weight-% solution in water at 20° C., and the reaction of the cellulose ether with the aliphatic monocarboxylic acid anhydride and/or the dicarboxylic acid anhydride and with the depolymerizing agent is conducted simultaneously or in sequence in one reaction device.

Abstract: A process for producing a cellulose ether acetate succinate comprises the step of reacting a cellulose ether with acetic anhydride, succinic anhydride and an depolymerizing agent, wherein the cellulose ether has an initial viscosity of at least 50 mPa-s, measured as a 2 weight-% solution in water at 20° C., and the reaction of the cellulose ether with acetic anhydride, succinic anhydride and the depolymerizing agent is conducted simultaneously or in sequence in one reaction device.

Abstract: A partially cross-linked esterified cellulose ether having A) groups of the formula —C(O)—R—COOA or a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, and B) having a molecular weight distribution such that [Wf(>100 k)?Wf(>100 k)XL]/Wf(>100 k)XL is at least 0.20, wherein Wf(>100 k) is the total weight fraction of the esterified cellulose ether that exceeds 100,000 g/mol, and Wf(>100 k)XL is the weight fraction that exceeds 100,000 g/mol of the methylated esterified cellulose ether is useful as enteric polymer for pharmaceutical dosage forms.

Abstract: Esterified cellulose ethers which have i) as ester groups aliphatic monovalent acyl groups or groups of the formula —C(O)—R—COOA or a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, and ii) a content of not more than 0.85 weight percent acetone-insoluble esterified cellulose ether particles, when the esterified cellulose ether is present in a mixture of 12.5 weight parts of esterified cellulose ether and 87.5 weight parts of acetone at 21° C., the weight percent acetone-insoluble esterified cellulose ether particles being based on the total weight of the esterified cellulose ether, wherein iii) not more than 14 percent of the acetone-insoluble esterified cellulose ether particles have a particle size of more than 90 micrometers.

Abstract: A process for recovering an esterified cellulose ether from a reaction product mixture obtained from a reaction of (a) a cellulose ether with (b) an aliphatic monocarboxylic acid anhydride or a di- or tricarboxylic acid anhydride or a combination of an aliphatic monocarboxylic acid anhydride and a di- or tricarboxylic acid anhydride, comprises the steps of (i) contacting the reaction product mixture with an aqueous liquid to precipitate the esterified cellulose ether from the reaction product mixture, (ii) isolating the precipitated esterified cellulose ether from the mixture obtained in step (i), and (iii) suspending the isolated esterified cellulose ether in an aqueous liquid to provide a suspension having a temperature of at least 28° C., and (iv) recovering the esterified cellulose ether from the suspension of step (iii).

Abstract: Esterified cellulose ethers which have i) as ester groups aliphatic monovalent acyl groups or a combination of aliphatic monovalent acyl groups and groups of the formula ——C(O)—R—COOA wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, ii) a weight average molecular weight Mw of from 80,000 Dalton to 220,000 Dalton, iii) a Polydispersity Mw/Mn of from 1.3 to 4.0, and iv) an Mz/Mn of not more than 18.5, when the weight average molecular weight Mw, the number average molecular weight Mn and the z-average molecular weight Mz are measured by SEC-MALLS using as mobile phase a mixture produced from 40 parts by volume of acetonitrile and 60 parts by volume of aqueous buffer containing 50 mM NaH2—PO4 and 0.1 M NaNO3. are useful as enteric polymers for pharmaceutical dosage forms.