59results about How to "Reduce hydrolysis reaction" patented technology

The invention discloses a method for synthesizing PODE through condensation, oxidation, polycondensation and etherification of methyl alcohol. The method includes the steps that firstly, methylal with the mass purity of 85%-99.9% is prepared through a reaction of the methyl alcohol and diluted methanal; secondly, the methylal and air are catalyzed and oxidized by iron-molybdenum catalysts to prepare methanal with the mass purity of not less than 70%; thirdly, the methanal is subjected to polycondensation and then is refined to obtain triformol with the mass purity of not less than 99.9%; fourthly, the methylal and the triformol are subjected to etherification, reactive distillation and dehydration and are refined to obtain PODE3-8 with the mass purity of over 99%. By the adoption of the method, the single-pass yield of the PODE is increased from 40%-50% to 95%, the yield of the PODE3-8 is increased from 20% to 90%, product distribution is more reasonable, and the product purity is improved from 50% to 99%. The PODE is wide in application prospect and remarkable in economic, social and environmental benefit.

The invention provides a metal-free sulfur-doped carbon material hydrogen peroxide reduction catalyst and a preparation method. The preparation method is characterized by comprising the following steps: putting benzyl disulfide and a carbon material into sufficient ethanol according to a mass ratio of (5-6): (95-94), ultrasonically treating the mixture for 0.5 to 1 hour, centrifuging the mixture to remove the upper substances, vacuum drying the mixture for 5 to 6 hours at the temperature of 50 to 60 DEG C to form solid powder, putting the solid powder into a high-temperature furnace to be reacted for 7 to 8 hours at the temperature of 800 to 900 DEG C under the protection of nitrogen, cooling the solid powder to room temperature under the protection of nitrogen to obtain the sulfur-doped carbon material hydrogen peroxide reduction catalyst. The sulfur is used for substituting carbon to form S-C bonds to form an activity center of the electroreduction of H2O2. The source of the raw material is wide, and the price is low. Not only is the electrochemical activity high, but also the stability is high, and the toxicity resistance is high. The hydrolysis reaction of the H2O2 can be prevented, and the oxygen can be reduced. The electric oxidation performance and utilization rate of the H2O2 can be greatly improved.

The invention provides a drying method for hyaluronic acid, comprising the following steps: adding an organic solvent I containing volatile silicone oil to a solution containing hyaluronic acid, and discarding the supernatant after precipitation; The organic solvent II containing volatile silicone oil is washed to obtain a precipitate, and the product is obtained after drying. The volume fraction of the volatile silicone oil in the organic solvent I is 1%-10%; the volume fraction in the organic solvent II is 20%-60%. The hyaluronic acid drying method provided by the present invention is suitable for hyaluronic acid samples with different molecular weights and different concentrations. After drying by the method of the present invention, the weight loss on drying does not exceed 5%, and the residual organic solvents all meet the regulations.