Catalytic system for cellulose acylation process for producing said catalytic system, and for its practical application

A cellulose acetylation process for producing cellulose acetates having a higher degree of polymerization and controllable degree of substitution comprising

• activating cellulose with acetic acid;
• preparation, in the absence of cellulose, of a catalytic system comprising an adduct of sulfuric acid with N,N-dimethylacetamide and free N,N-dimethylacetamide with mole ratio equal to 1.0:0.1-0.4;
• preparing an acetylating mixture comprising at least said catalytic system in an amount of 7.0-30.0 wt. % of cellulose weight in terms of sulfuric acid and acetic anhydride;
• and
• acetylating activated cellulose with said acetylating mixture at a temperature of 10° C.-90° C. and module equal to 3.6-7.0.

A process for producing acetone-soluble primary cellulose acetates having a higher degree of polymerization, comprising

• activating cellulose with acetic acid;
• preparation, in the absence of cellulose, of a catalytic system comprising an adduct of sulfuric acid with N,N-dimethylacetamide and free N,N-dimethylacetamide with mole ratio equal to 1.0:0.2-0.4;
• preparing an acetylating mixture comprising at least said catalytic system in an amount of 20.0-30.0 wt. % of cellulose weight in terms of sulfuric acid and acetic anhydride;
• acetylating activated cellulose with said acetylating mixture at a temperature of 10° C.-90° C. and module equal to 4.0-7.0;
• and
• further treating the resulting cellulose acetate with water, acetic acid and magnesium acetate or sodium acetate at a first stage and at a second stage;
• at the first stage treating at a temperature of 70.0° C.-85.0° C. for 1.0-2.0 hours with 20.0-50.0 wt.pt of water, 25.0-50.0 wt.pt of acetic acid, 10.0-40.0 wt.pt of magnesium acetate or sodium acetate per 100.0 wt.pt of cellulose;
• and
• at the second stage treating at a temperature of 65° C.-70° C. for 1.0-2.0 hours with 45.0-100.0 wt.pt of water, 45.0-105.0 wt.pt. of acetic acid per 100.0 wt.pt. of cellulose.

A process for producing mixed cellulose esters such as acetopropionates and acetobutyrates at low module comprising

• activating cellulose with acetic acid;
• preparation, in the absence of cellulose of a catalytic system comprising an adduct of sulfuric acid with N,N-dimethylacetamide, an adduct of perchloric acid with N,N-dimethylacetamide in an amount of 0.5 mole and free N,N-dimethylacetamide in an amount of max. 0.1 mole per 1.0 mole of an adduct of sulfuric acid with a N,N-dimethylacetamide;
• preparing an acylating mixture comprising at least said catalytic system in an amount of 10.0-20.0 wt. % of sulfuric acid and 5.0-10.0 wt. % of perchloric acid of cellulose weight in terms of said acids, as well as propionic anhydride or butyric anhydride;
• and
• acylating activated cellulose with said acylating mixture at a temperature of 10° C.-90° C. and module about 5.0, followed by hydrolysis and isolation of the end product.