摘要:
A process for producing polycarboxylic acids or salts thereof by contacting a polysaccharide with nitrogen dioxide and dinitrogen tetroxide at a charging temperature in the range from the boiling point of nitrogen dioxide under a particular pressure to a temperature which is 50.degree. C. higher than said boiling point, oxidizing the primary alcohol groups of the polysaccharide at a temperature which is at least about 10.degree. C. above said charging temperature to convert the primary alcohol groups into carboxyl groups, and optionally, at least partially neutralizing the carboxylic acid groups formed.
摘要:
A process for producing polycarboxylic acids or their salts from polysaccharides is provided. Solid particulate polysaccharides having at least one primary alcohol group in the polysaccharides are oxidized with nitrogen dioxide in a fluid bed. The fluidizing gas contains nitrogen dioxide and the process is operated at a pressure of from 0.5 to 12 bars and a temperature between the boiling point of nitrogen dioxide and 160.degree. C. At least two moles of nitrogen dioxide for the equivalent of the primary alcohol groups reacted over the entire reaction are provided.
摘要:
A process for the production of polycarboxylic acids or salts thereof from polysaccharides by oxidation with nitrogen dioxide/dinitrogen tetroxide with at least partial conversion of the primary alcohol groups of the polysaccharides into carboxyl groups and optionally at least partial neutralization of the carboxylic acid groups formed is provided. The oxidation reaction is carried out in a closed reaction system in the presence of oxygen under pressures of 2 bar to 10 bar and at a temperature above room temperature. Nitrogen dioxide/dinitrogen tetroxide is used in such quantities that, in the event of a theoretically complete shift of the equilibrium onto the nitrogen dioxide side, the nitrogen dioxide is present in quantities of at most 2 mole equivalents, based on the content of monomer unit of the polysaccharide containing one primary alcohol group.
摘要:
A continuous process for the production of polycarboxylic acids or salts thereof from polysaccharides involving contacting a polysaccharide with an oxidizing agent selected from the group consisting of nitrogen dioxide, dinitrogen tetroxide, or an equilibrium mixture thereof in the absence of oxygen at a temperature above 80 .degree.C. and at a pressure of from about 3 bar to about 15 bar absolute and for a tirne period of from about 1 to about 30 minutes to form a reducd gaseous product and a polysaccharide product wherein the primary alcohol groups of said polysaccharide product are at least partially converted to carboxyl groups.
摘要:
The setting properties of an .alpha.-cyanoacrylate adhesive composition areccelerated by adding thereto a hydroxyl group derivative of an .alpha.-, .beta.- or .gamma.-cyclodextrin which is at least partly soluble in the .alpha.-cyanoacrylate.
摘要:
The invention relates to a process for deinking wastepaper in the presence of at least partly water-soluble polymers and/or copolymers containing amino and/or ammonium groups. Two examples of appropriate polymers/copolymers are neutralized polyethyleneimine and quaternized hydroxyethyl cellulose.
摘要:
A process and surfactant-containing composition for reducing incrustation on washed laundry. The composition contains finely-divided, water-insoluble builder components and an at least partly water-soluble co-builder which is the oxidation product of polyglucosans wherein, on average, at least 15 mole percent thereof consists of oxidized anhydroglucose units corresponding to formula I ##STR1## and which have an average molecular weight of up to 15,000.
摘要:
The invention relates to a process for the removal of fillers from waste paper, after floatation of the printing ink, in the presence of at least partly water-soluble polymers and/or copolymers having number average molecular weights of 1,000 to 500,000 by flotation.
摘要:
A process for producing solid polycarboxylic acid salts from polysaccharides with gaseous nitrogen dioxide and dinitrogen tetroxide to at least partially convert the primary alcohol groups of the polysaccharides into carboxyl groups and form a solid polycarboxylic acid and then mixing the polycarboxylic acid with a solid neutralizing agent to at least partially neutralized the carboxylic acid groups of the polycarboxylic acid.
摘要:
The process of controlling foam in a foam-generating system by adding to the system a foam-inhibiting effective amount of a block copolymer containing alkylene oxide units obtained by reacting a homopolymer or copolymer of alkylene oxides with a diisocyanate or a dicarboxylic acid derivative containing 2 to 44 carbon atoms.