Processes for purifying acetic acid by distilling a process stream in a column in which acetic anhydride is formed in the lower portion of the column. The product stream withdrawn from the column comprises acetic acid, water at a concentration of no more than 0.2 wt. %, and acetic anhydride at a concentration of no more than 600 wppm. The process further comprises hydrating the acetic anhydride in the product stream to form a purified acetic acid product comprising acetic anhydride at a concentration of no more than 50 wppm.

Processes for purifying acetic acid by distilling a process stream in a column in which acetic anhydride is formed in the lower portion of the column. The product stream withdrawn from the column comprises acetic acid, water at a concentration of no more than 0.2 wt. %, and acetic anhydride at a concentration of no more than 600 wppm. The process further comprises hydrating the acetic anhydride in the product stream to form a purified acetic acid product comprising acetic anhydride at a concentration of no more than 50 wppm.

Disclosed is the integration of the production of acetic anhydride from ketene, and the acetylation of wood using acetylation fluid comprising acetic acid and acetic anhydride. The invention involves recovering acetylation fluid from wood acetylation, and sending this to an acetic anhydride distillation unit belonging to the acetic anhydride production plant.

Disclosed is the integration of the production of acetic anhydride from ketene, and the acetylation of wood using acetylation fluid comprising acetic acid and acetic anhydride. The invention involves recovering acetylation fluid from wood acetylation, and sending this to an acetic anhydride distillation unit belonging to the acetic anhydride production plant.

Processes for purifying acetic acid by distilling a process stream in a column in which acetic anhydride is formed in the lower portion of the column. The product stream withdrawn from the column comprises acetic acid, water at a concentration of no more than 0.2 wt. %, and acetic anhydride at a concentration of no more than 600 wppm. The process further comprises hydrating the acetic anhydride in the product stream to form a purified acetic acid product comprising acetic anhydride at a concentration of no more than 50 wppm.

Processes for purifying acetic acid by distilling a process stream in a column in which acetic anhydride is formed in the lower portion of the column. The product stream withdrawn from the column comprises acetic acid, water at a concentration of no more than 0.2 wt. %, and acetic anhydride at a concentration of no more than 600 wppm. The process further comprises hydrating the acetic anhydride in the product stream to form a purified acetic acid product comprising acetic anhydride at a concentration of no more than 50 wppm.

The present invention concerns a process for manufacturing a carboxylic anhydride by reaction of a carboxylic acid with a ketene, and the use of the thus prepared carboxylic anhydride in a process for acylation of polysaccharides.

The present invention concerns a process for manufacturing a carboxylic anhydride by reaction of a carboxylic acid with a ketene, and the use of the thus prepared carboxylic anhydride in a process for acylation of polysaccharides.

The present invention concerns a process for manufacturing a fraction comprising carboxylic acid anhydride by reaction of a fraction comprising carboxylic acid with a ketene, and the use of the fraction comprising carboxylic acid anhydride in a process for acylation of polysaccharides.

The present invention concerns a process for manufacturing a fraction comprising carboxylic acid anhydride by reaction of a fraction comprising carboxylic acid with a ketene, and the use of the fraction comprising carboxylic acid anhydride in a process for acylation of polysaccharides.