Dow Global Technolgoies LLC

Other

Nutrition & Biosciences USA 1, LLC

Matthias Sprehe

Oliver Petermann

Meinolf Brackhagen

Robert B Appell

Nicholas S Grasman

Alexandra Hild

Warren Kenyon Miller

Matthias Knarr

Robert Thomas Nilsson

Roland Adden

Robert L Schmitt

Charles B Mallon

Steven J Guillaudeu

Erik-Andreas Klohr

David M Meunier

Yongfu Li

Robert E Scheid, Jr

Bettina Hoelzer

Jöerg Neubauer

Martin Kowollik

Michael Schreck

Sonja Menz

David W Ziettlow

Richard A Engelman

Andrew C Arthur

Axel Altmann

Werner Viereck

Oliver Peterman

Robert Bruce Appell

Robert E Scheid Jr

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.

Process for producing a crosslinked cellulose ether

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 &#x2014;C(O)&#x2014;R&#x2014;COOA wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, ii) a weight average molecular weight Mof from 80,000 Dalton to 220,000 Dalton, iii) a Polydispersity M/Mof from 1.3 to 4.0, and iv) an M/Mof not more than 18.5, when the weight average molecular weight M, the number average molecular weight Mn and the z-average molecular weight Mare 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 NaH&#x2014;POand 0.1 M NaNO. are useful as enteric polymers for pharmaceutical dosage forms.

Esterified cellulose ethers of high molecular weight and homogeneity

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].

Process of preparing an esterified cellulose ether in the presence of an alkali metal carboxylate and an aliphatic carboxylic acid

Esterified cellulose ethers which have i) as ester groups aliphatic monovalent acyl groups or groups of the formula &#x2014;C(O)&#x2014;R&#x2014;COOA or a combination of aliphatic monovalent acyl groups and groups of the formula &#x2014;C(O)&#x2014;R&#x2014;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&#xb0; 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.

Esterified cellulose ethers of low acetone-insoluble content

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.

Efficient process for preparing an ester of a cellulose ether

Esterified cellulose ethers which comprise (i) groups of the formula &#x2014;C(O)&#x2014;R&#x2014;COOA or (ii) a combination of aliphatic monovalent acyl groups and groups of the formula &#x2014;C(O)&#x2014;R&#x2014;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&#xb7;s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20&#xb0; C., and a weight average molecular weight Mof at least 220,000 Dalton, or which have a viscosity of up 100 mPa&#xb7;s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20&#xb0; C., and a weight average molecular weight Mof at least 310,000 Dalton are useful for preparing solid dispersions comprising drugs.

Esterified cellulose ethers of very high molecular weight

A partially cross-linked esterified cellulose ether having A) groups of the formula &#x2014;C(O)&#x2014;R&#x2014;COOA or a combination of aliphatic monovalent acyl groups and groups of the formula &#x2014;C(O)&#x2014;R&#x2014;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(&#x3e;100 k)&#x2212;Wf(&#x3e;100 k)XL]/Wf(&#x3e;100 k)XL is at least 0.20, wherein Wf(&#x3e;100 k) is the total weight fraction of the esterified cellulose ether that exceeds 100,000 g/mol, and Wf(&#x3e;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.

Partially cross-linked esterified cellulose ethers

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&#xb0; C., and (iv) recovering the esterified cellulose ether from the suspension of step (iii).

Process for recovering an esterified cellulose ether from a reaction product mixture

Esterified cellulose ethers which comprise (i) aliphatic monovalent acyl groups or (ii) groups of the formula &#x2014;C(O)&#x2014;R&#x2014;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 &#x2014;C(O)&#x2014;R&#x2014;COOA, which have a viscosity of up to 2.33 mPa&#xb7;s, measured as a 2.0 wt % solution of the esterified cellulose ether in 0.43 wt % aqueous NaOH at 20&#xb0; C., and which have a viscosity of up to 13 mPao&#xb7;s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20&#xb0; C. are useful for preparing solid dispersions comprising drugs.

Esterified cellulose ethers of low viscosity

A reaction product mixture is obtained from a reaction of (a) a cellulose ether with (b) an aliphatic monocarboxylic acid anhydride or with a di- or tricarboxylic acid anhydride or with a combination of an aliphatic monocarboxylic acid anhydride and a di- or tricarboxylic acid anhydride in the presence of (c) an aliphatic carboxylic acid. A process for precipitating an esterified cellulose ether from this reaction product mixture comprises the step of contacting the reaction product mixture with water and subjecting the combination of water and the reaction product mixture to a shear rate of at least 800 s. The precipitated esterified cellulose ether can be recovered as a non-tacky product.

Process of preparing an ester of a cellulose ether

A process for treating a polysaccharide with a dialdehyde in the presence of from 10 to 40 weight percent of water, based on the total weight of polysaccharide and water, is beneficially conducted in a mixing device characterized by a FROUDE number FRof larger than 11, wherein &#x3c9;is the angular frequency in sec-1 and is defined as 2*&#x3c0;*RPM/60, RPM is the rotational speed of the mixing device in revolutions per minute, Ris the radius of the mixing device in m, and g is the acceleration due to gravity in m/s. 

Treatment of polysaccarides with dialdehydes

In a method of removing alkylene halogenohydrin from a cellulose ether the cellulose ether is provided, water is added to the cellulose ether and subsequently alkylene halogenohydrin and water is removed from the cellulose ether by evaporation. Alternatively steam or a steam mixture can be sparged across or through the cellulose ether to remove halogenohydrin from the cellulose ether.

Method of removing alkylene halogenohydrin from cellulose ether

The present invention relates to a process for the production of alkali cellulose for the production of alkali cellulose and, optionally, cellulose ethers from cellulose in the presence of alkali and, if applicable, with alkylating and/or hydroxyalkylating agent(s) comprising the reaction of a cellulose with an alkali metal hydroxide, wherein the alkali metal hydroxide is mixed with cellulose in a mixing apparatus, the mixing apparatus () having an upper region () with a first cross-section and a lower region () with a second cross-section, the second cross-section being the same as or smaller than the first cross-section and comprising at least one non-horizontally oriented mixing device ().

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Walsrode, Germany

Matthias Sprehe