This invention relates to novel compositions comprising regioselectively substituted cellulose esters. One aspect of the invention relates to processes for preparing regioselectively substituted cellulose esters from cellulose dissolved in ionic liquids. Another aspect of the invention relates to the utility of regioselectively substituted cellulose esters in applications such as protective and compensation films for liquid crystalline displays.

This invention relates to novel compositions comprising regioselectively substituted cellulose esters. One aspect of the invention relates to processes for preparing regioselectively substituted cellulose esters from cellulose dissolved in ionic liquids. Another aspect of the invention relates to the utility of regioselectively substituted cellulose esters in applications such as protective and compensation films for liquid crystalline displays.

The present invention is to provide a cellulose acetate that has a low total degree of acetyl substitution and a degree of acetyl substitution at 6-position that is lower compared to the degrees of acetyl substitution at 2-position and 3-position of a glucose ring, and has excellent water solubility. A cellulose acetate having: a total degree of acetyl substitution of 0.4 or greater and 0.9 or less, a proportion of a degree of acetyl substitution at 6-position in the total degree of acetyl substitution of 0% or greater and 18% or less, and a light transmittance at 660 nm of 5% or greater in 4 wt. % aqueous solution.

The present invention is to provide a cellulose acetate that has a low total degree of acetyl substitution and a degree of acetyl substitution at 6-position that is lower compared to the degrees of acetyl substitution at 2-position and 3-position of a glucose ring, and has excellent water solubility. A cellulose acetate having: a total degree of acetyl substitution of 0.4 or greater and 0.9 or less, a proportion of a degree of acetyl substitution at 6-position in the total degree of acetyl substitution of 0% or greater and 18% or less, and a light transmittance at 660 nm of 5% or greater in 4 wt. % aqueous solution.

Disclosed is a process for solubilising cellulose and coagulating the resulting solution to form a cellulose-containing material. The process comprises contacting a cellulose source with a solvent comprising zinc ions and formic acid to provide a solution, coagulating the solution to provide a solid material, and isolating the solid material after treatment, to provide the cellulose-containing material. The process further involves a method of stabilising the solid material, such as treating the solid material with a reducing agent, treating the solid material in water at an elevated temperature, treating the solid material with an organic solvent, pre-treating the cellulose-containing solution with a freeze-thaw cycle and/or isolating a cellulose formate intermediate. The process can further comprise solubilising protein and coagulating the resulting solution to form a cellulose/protein-containing material.

Disclosed is a process for solubilising cellulose and coagulating the resulting solution to form a cellulose-containing material. The process comprises contacting a cellulose source with a solvent comprising zinc ions and formic acid to provide a solution, coagulating the solution to provide a solid material, and isolating the solid material after treatment, to provide the cellulose-containing material. The process further involves a method of stabilising the solid material, such as treating the solid material with a reducing agent, treating the solid material in water at an elevated temperature, treating the solid material with an organic solvent, pre-treating the cellulose-containing solution with a freeze-thaw cycle and/or isolating a cellulose formate intermediate. The process can further comprise solubilising protein and coagulating the resulting solution to form a cellulose/protein-containing material.

Disclosed is a process for solubilising cellulose and coagulating the resulting solution to form a cellulose-containing material. The process comprises contacting a cellulose source with a solvent comprising zinc ions and formic acid to provide a solution, coagulating the solution to provide a solid material, treating the solid material, and isolating the solid material after treatment, to provide the cellulose-containing material. The process can further comprise solubilising protein and coagulating the resulting solution to form a cellulose/protein-containing material. The cellulose-containing materials and cellulose/protein-containing materials can be produced, for example, as reconstituted fibres and films.

Disclosed is a process for solubilising cellulose and coagulating the resulting solution to form a cellulose-containing material. The process comprises contacting a cellulose source with a solvent comprising zinc ions and formic acid to provide a solution, coagulating the solution to provide a solid material, treating the solid material, and isolating the solid material after treatment, to provide the cellulose-containing material. The process can further comprise solubilising protein and coagulating the resulting solution to form a cellulose/protein-containing material. The cellulose-containing materials and cellulose/protein-containing materials can be produced, for example, as reconstituted fibres and films.

An object is to provide a cellulose acetate remarkably good in hue even when a low-quality pulp is used.

A method for producing the cellulose acetate includes a step (1) of crushing a wood pulp, a step (2) of bringing the crushed wood pulp into contact with acetic acid to subject the pulp to pretreat the wood pulp, a step (3) of causing the wood pulp to react with acetic anhydride after the pretreatment to acetylate the pulp, a step (4) of hydrolyzing the cellulose acetate, which is yielded by the acetylation, and a step (5) of precipitating the cellulose acetate, an acetylation degree of which is adjusted by the hydrolysis. In the hydrolyzing step (4), in a hydrolysis reaction system, a concentration of oxygen is set to 3% or less.

The invention concerns a process for the manufacture of an acylated polysaccharide which comprises. (a) reacting a polysaccharide with an acylating agent to produce an acylated polysaccharide and (b) washing the acylated polysaccharide with water containing from 0.05 to 15 mg/l Ca.sup.2+-ions (c) recovering the washed acylated polysaccharide and an aqueous phase containing carboxylic acid from step (b).