35results about How to "Low color level" patented technology

A process comprising reacting a mono- or di-carboxylic acid and / or acid anhydride with a glycol ether in the presence of phosphoric acid to produce a glycol ether ester product having low color and low VOC content.

The invention provides a method for preparing cefuroxime sodium. The method comprises a step of reacting cefuroxime acid with mixed sodium salt to produce the cefuroxime sodium, wherein the mixed sodium salt comprises two or three of sodium acetate, sodium lactate and sodium iso-octoate. The product prepared by the method has the advantages of uniform crystal dispersion, greatly improved fluidityand easy packaging; the solubility of the product is greatly improved, and compared with similar products prepared by the conventional methods, the dissolution time is the shortest; the method greatly shortens the time for washing, filtering and drying the product, reduces the opportunities of powder exposure and human contact, more easily controls visible foreign matters in the product and effectively reduces the number of insoluble particles in the product; because the method improves the crystal form of the product, the crystal is easy to wash and dry, the time of the product at a high temperature is shortened and the stability of the product is improved effectively. The color grade of the product is further reduced, and the product is more stable and uniform and has better performanceon indexes such as the color grade, content, impurities and the like.

A display system and driving method thereof are capable of outputting a low luminance of red light, especially through descending a color level of red signals when displayed. The display system includes a display device and an image processing device. The image processing device outputs the red signals to the display device for displaying thereon. The color level of red signals is descended by a display chip or a switch device to allow the display device to display images with low luminance of red light, so that the display device is viewable through a night-vision device.

The invention discloses a method for refining cefathiamidine, belonging to the field of chemical pharmacy, comprising dissolving crude cefathiamidine with a dissolving agent, adding a stabilizing regulator, and using an alumina adsorption column for secondary decolorization; the invention can effectively reduce the The color grade of cefathiamidine, the obtained cefathiamidine crystal particles are uniform, the purity is high, the stability is good, and the product yield is high, the preparation method is simple and easy to control, and it is suitable for large-scale industrial production.

The invention discloses a method for purifying cefepime hydrochloride, belonging to the field of chemical pharmacy, using cefepime hydrochloride arginine as a raw material, adding a complexing agent to a solution of cefepime hydrochloride arginine, decolorizing, and then adding Adding a dispersant and a crystallizer to the decolorizing solution for crystallization to obtain cefepime hydrochloride; the invention can fully recycle cefepime hydrochloride arginine that does not meet the quality standards, and the prepared cefepime hydrochloride has a content of It has the advantages of high concentration, less impurities and good stability, simple preparation method, energy saving and environmental protection, and is suitable for large-scale industrial production.

The invention relates to a method for preparing an antibacterial compound, in particular to a method for preparing a ceftezole sodium compound. The method comprises the following steps of: 1, synthesizing TZT II, and reacting 2-mercapto-1,3,4 thiadiazole and 7-aminocephalosporanic acid (ACA) to obtain TZT, wherein dimethyl carbonate is used as a reaction solvent; a boron trifluoride-dimethyl carbonate complex is used as a catalyst; after reaction, the agent used by adjusting pH of reaction liquid is sodium carbonate; the weight ratio of boron trifluoride to 7-ACA is 0.7 to 1.3; and 2, synthesizing anhydride I, namely reacting 1H-tetrazole-1-acetic acid and pivaloyl chloride to obtain anhydride; 3, synthesizing ceftezole III, namely reacting TZT II and anhydride I to obtain ceftezole; and 4, synthesizing ceftezole sodium IV, namely reacting ceftezole and sodium salt to obtain ceftezole sodium IV, wherein salt is sodium hydroxide.

The invention discloses a method for refining cefanizidime dibenzylethylenediamine salt, which belongs to the technical field of medicine. The crude product of cefanizidime salt is ion-exchanged with a resin, decolorized with a decolorizing agent, and then synthesized with a transamination agent. Salt reaction, and then crystallization with a precipitating agent to obtain the refined cefanixime dibenzylethylenediamine salt. The cefanisidine dibenzylethylenediamine salt prepared by the present invention has high purity, few impurities and low color grade, and the refining method of the present invention has the advantages of simple process, energy saving and environmental protection, suitable for large-scale industrial production, and the like.

The invention discloses a preparation method of cefotaxime sodium. Ceftizoxime acid used as the initial raw material reacts with anhydrous sodium acetate to generate the cefotaxime sodium. In such process, purified water, butanol and acetone are selected as crystallizing solvents to control the mixing speed and crystallization temperature in the crystallization process, so that the finally obtained cefotaxime sodium has favorable flowability and can satisfy the subpackaging requirements in production. Various quality indexes of the obtained cefotaxime sodium conform to the requirements for medicinal standard, and thus, the cefotaxime sodium can satisfy the demands for clinical application.

The invention relates to a method for recrystallizing cefuroxime sodium, which is used for solving the problem of the refining of cefuroxime sodium raw material medicaments with darker colors. In the technical scheme, white crystalline powder recrystallized by the cefuroxime sodium is prepared by the following four steps of: a, preparing crude product solution; b, preparing a crystallization solvent; c, crystallizing; and d, discharging. By the method, the yield is over 83 percent, and the color level and the pH value of final products meet the pharmacopoeial standard; and the method is suitable for recrystallizing the raw material medicaments with unqualified color levels.

The invention discloses a method for purifying cefepime hydrochloride, which belongs to the field of chemical pharmacy. The crude product of cefepime hydrochloride is used as a raw material, the pH of the solution solution of the crude product of cefepime hydrochloride is adjusted, a dispersant is added, and the isoelectric point is crystallized to obtain Cefepime hydrochloride; the invention can improve the purity of cefepime hydrochloride, and the prepared cefepime hydrochloride has the advantages of low color grade, uniform particle size and good fluidity.