# US 9,040,685 B2 · Cellulose interpolymers and method of oxidation

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- Number: US 9,040,685 B2
- Document ID: US9040685B2
- Status: Granted
- Kind: B2
- Application number: 13/728,216
- Filed: 2012-12-27
- Published: 2013-05-09
- Granted: 2015-05-26
- Earliest claimed: 2003-11-28
- Assignees: Eastman Chemical Company
- Applicants: Eastman Chemical Company
- Inventors: Charles Michael Buchanan; Norma Lindsey Buchanan; Susan Northrop Carty; Chung-Ming Kuo; Juanelle Little Lambert; Michael Orlando Malcolm; Jessica Dee Posey-Dowty; Thelma Lee Watterson; Matthew Davie Wood; Margaretha Soderqvist Lindblad
- Web page: https://patentgrep.com/patent/US9040685B2

## CPC

- C08B 3/06: Cellulose acetate {, e.g. mono-acetate, di-acetate or tri-acetate}
- A61K 9/2054: {Cellulose; Cellulose derivatives, e.g. hydroxypropyl methylcellulose}
- A61K 9/4891: {Coated capsules; Multilayered drug free capsule shells (with drug coating for immediate release A61K9/4808; osmotic devices A61K9/0004)}
- A61K 47/38: Cellulose; Derivatives thereof
- C08B 3/04: Cellulose formate
- C08B 3/08: of monobasic organic acids with three or more carbon atoms, {e.g. propionate or butyrate}
- C08B 3/16: Preparation of mixed organic cellulose esters {, e.g. cellulose aceto-formate or cellulose aceto-propionate}
- C08B 3/22: Post-esterification treatments, including purification
- C08B 3/24: Hydrolysis or ripening
- C08B 15/02: Oxycellulose; Hydrocellulose; {Cellulosehydrate, e.g. microcrystalline cellulose}
- C08B 15/04: Carboxycellulose, e.g. prepared by oxidation with nitrogen dioxide
- C08L 1/10: Esters of organic acids {, i.e. acylates}
- C08L 1/12: Cellulose acetate
- C08L 1/14: Mixed esters, e.g. cellulose acetate-butyrate
- C09D 17/00: Pigment pastes, e.g. for mixing in paints (artists' paints C09D5/06)
- A61K 9/19: lyophilised {, i.e. freeze-dried, solutions or dispersions (lyophilised products with subsequent particle size reduction A61K9/14; granules or pellets made by lyphilisation A61K9/1682; solid oral dosage forms made by lyophilisation A61K9/2095; lyophilisation additives A61K47/00)}
- A61K 9/2866: {Cellulose; Cellulose derivatives, e.g. hydroxypropyl methylcellulose}
- C08B: POLYSACCHARIDES; DERIVATIVES THEREOF (polysaccharides containing less than six saccharide radicals attached to each other by glycosidic linkages C07H; fermentation or enzyme-using processes C12P19/00; sugar industry C13; production of cellulose D21)
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)

## Abstract

This invention provides cellulose ester interpolymers, and methods of oxidizing cellulose interpolymers and cellulose ester interpolymers. The invention also provides routes to access carboxylated cellulose ester derivatives with high acid numbers wherein the carboxyl group is attached directly to the cellulose backbone by a carbon-carbon bond. Through functionalization of an intermediate aldehyde, the corresponding cationic or zwitterionic cellulose ester derivatives can also be accessed. The interpolymers of the present invention have a number of end-use applications, for example, as binder resins in various types of coating compositions and as drug delivery agents.

## Claims

### Claim 1

A method for preparing a stable form of a cellulose formate ester interpolymer comprising:
(1) mixing formic acid, water, and an C2-C12 acyl anhydride to form a mixed anhydride mixture at a first contact temperature, wherein the C2-C12 acyl anhydride comprises acetic anhydride, propionic anhydride, butyric anhydride, or mixtures thereof;
(2) contacting the mixed anhydride mixture and a cellulose compound to form a reaction mixture at a second contact temperature;
(3) adding an acid catalyst to the reaction mixture, wherein the at catalyst is sulfuric acid;
(4) passing of a formylation period to form a homogenous solution comprising the cellulose formate ester interpolymer;
wherein the cellulose formate ester interpolymer has a degree of substitution per anhydroglucose unit of formate of about 0.5 to about 1.5.

### Claim 2 (depends on 1)

The method of claim 1, wherein the resulting cellulose formate ester interpolymer has a degree of substitution per anhydroglucose unit of formate of about 0.7 to about 1.2.

### Claim 3 (depends on 1)

The method of claim 1, wherein the resulting cellulose formate ester interpolymer has a degree of substitution per anhydroglucose unit of formate of about 0.9 to about 1.1.

### Claim 4 (depends on 1)

The method of claim 1, wherein the acid catalyst is added in an amount ranging from about 0.25 to about 15 weight percent based on weight of cellulose compound.

### Claim 5 (depends on 1)

The method of claim 1, wherein the amount of formic acid added in step (1) is from about 4 to about 15 molar equivalents based on moles of cellulose compound.

### Claim 6 (depends on 1)

The method of claim 1, wherein the first contact temperature ranges from about −10 to about 15° C.

### Claim 7 (depends on 1)

The method of claim 1, wherein the second contact temperature ranges from about 10 to about 70° C.

### Claim 8 (depends on 1)

The method of claim 1, further comprising the step of isolating the resulting cellulose formate ester interpolymer.

### Claim 9 (depends on 1)

The method of claim 1, wherein the resulting cellulose formate ester interpolymer has a formate relative degree of substitution (RDS) at C6 of at least 0.4.

### Claim 10 (depends on 1)

The method of claim 1, wherein the resulting cellulose formate ester interpolymer has a formate relative degree of substitution (RDS) at C6 of at east 0.6.

### Claim 11

A method for preparing a stable form of a cellulose ester interpolymer comprising:
(1) mixing formic acid, water, and an C2-C12 acyl anhydride to form a mixed anhydride mixture at a first contact temperature;
(2) contacting the mixed anhydride mixture and a cellulose compound to form a reaction mixture at a second contact temperature;
(3) adding an acid catalyst to the reaction mixture;
(4) passing of a formylation period;
(5) adding a C2-C12 acyl anhydride to the reaction mixture;
(6) heating the reaction mixture to a third contact temperature;
(7) passing of an acylation period;
wherein a resulting cellulose ester interpolymer has a degree of substitution per anhydroglucose unit of C2-C12 acyl of but 1.5 to about 2.5, and a degree of substitution per anhydroglucose unit of formate of about 0.5 to about 1.5.

### Claim 12 (depends on 11)

The method of claim 11, wherein the resulting cellulose ester interpolymer has a formate relative degree of substitution (RDS) at 06 of at east 0.6.

### Claim 13 (depends on 11)

The method of claim 11, wherein the resulting cellulose ester interpolymer has a formate relative degree of substitution (RDS) at C6 of at least 0.4.

### Claim 14 (depends on 13)

The method of claim 13, wherein the resulting cellulose ester interpolymer has a degree of substitution per anhydroglucose unit of C2-C12 acyl of 1.8 to 2.3, and a degree of substitution per anhydroglucose unit of formate of 0.7 to 1.2.

### Claim 15 (depends on 13)

The method of claim 13, wherein the resulting cellulose ester interpolymer has a degree of substitution per anhydroglucose unit of C2-C12 acyl of 1.9 to 2.1, and a degree of substitution per anhydroglucose unit of formate of 0.9 to 1.1.

### Claim 16 (depends on 13)

The method of claim 13, wherein the acid catalyst is sulfuric acid.

### Claim 17 (depends on 13)

The method of claim 13, wherein the acid catalyst is added in an amount ranging from about 0.25 to about 15 weight percent based on weight of cellulose compound.

### Claim 18 (depends on 13)

The method of claim 13, wherein the amount of formic acid added in step (1) is from about 4 to about 13 molar equivalents based on moles of cellulose compound.

### Claim 19 (depends on 13)

The method of claim 13, wherein the first contact temperature ranges from about −10 to about 15° C.

### Claim 20 (depends on 13)

The method of claim 13, wherein the second contact temperature ranges from about 10 to about 70° C.

### Claim 21 (depends on 13)

The method of claim 13, wherein the third contact temperature ranges from about 40 to about 60° C.

### Claim 22 (depends on 13)

The method of claim 13, wherein the C2-C12 acyl anhydride, comprises acetic, propionic, butyric anhydride, or mixture thereof.

### Claim 23 (depends on 13)

The method of claim 13, further comprising the step of removing by hydrolysis or alcoholysis the formate ester groups substituted on the cellulose ester.

### Claim 24 (depends on 13)

The method of claim 13, further comprising the step of isolating the cellulose ester interpolymer.

### Claim 25 (depends on 13)

The method of claim 13, further comprising the step of:
adding an amino substituted cyclic nitroxyl derivative, a primary oxidant, and a terminal oxidant to the reaction mixture, wherein the reaction mixture has a pH of less than 4, and
passing of a reaction period sufficient to effect conversion of a C6 hydroxyl group of an anhydroglucose unit of the cellulose ester interpolymer.