5 results about "Methionine preparation" patented technology

The invention belongs to the technical field of microcapsule corrosion inhibitors, and discloses a microcapsule corrosion inhibitor with pH response and slow release effects and a preparation method and application thereof. The method comprises the following steps: 1) preparing syringaldehyde modified methionine; (2) preparing the octenyl succinic anhydride modified chitosan; 3) dissolving the octenyl succinic anhydride modified chitosan in an acetic acid solution to serve as an internal water phase, and dissolving polylactic acid and syringaldehyde modified methionine in an organic solvent to serve as an oil phase; mixing the internal water phase and the oil phase, and performing ultrasonic treatment to obtain a primary emulsion; polyvinyl alcohol and water are mixed to serve as an outer water phase; adding the external water phase into the primary emulsion, and stirring to obtain a final emulsion; and removing the solvent, removing impurities and drying to obtain the microcapsule. The microcapsule corrosion inhibitor disclosed by the invention has a continuous and stable slow release effect, excellent encapsulation performance and relatively good corrosion resistance and pH response. The corrosion inhibitor disclosed by the invention is used for metal corrosion prevention and anticorrosive paint.

The utility model relates to the field of methionine preparation, in particular to a device for separating methionine from compound amino acid, which comprises a bottom plate, the device further comprises a base, an auxiliary gear, a servo motor, a driving gear, an air guide pipe, a connector, a hose and an air pump, a washing tank is arranged on the left side of the upper surface of the bottom plate, and a liquid outlet pipe is arranged on the bottom surface of the washing tank; by arranging the servo motor, the output end of the servo motor can drive the driving gear to rotate during operation, the driving gear can drive the auxiliary gear meshed with the driving gear to rotate synchronously during rotation, the auxiliary gear can drive the air guide pipe to rotate during rotation, and the air pump is started; the air pump can send high-speed air flow into the air guide pipe through the hose and blow the high-speed air flow out of the end opening of the air guide pipe, so that air is blown to the surface of the semi-permeable membrane, filtered materials are blown away, penetration of the semi-permeable membrane can be avoided, and meanwhile the problem that the filtering capacity is reduced due to the fact that the materials filtered by the semi-permeable membrane are gathered and accumulated is solved.

The application discloses a preparation method of D,L-methionine, which comprises the following steps: mixing glycine ethyl ester hydrochloride, benzaldehyde and a solvent, heating to 40-50 DEG C, opening a negative pressure and a reflux water separation device, keeping the system outside steam by adjusting the negative pressure, and dropping triethylamine; solid-liquid separation is performed on the reaction solution, the liquid is heated to reflux, 2-chloroethyl methyl sulfide is dropped, and reflux reaction is continuously performed; the temperature of the reaction solution is reduced to less than or equal to 60 DEG C, the reflux is stopped, and hydrogen chloride gas is introduced; solid-liquid separation is performed on the reaction solution, the liquid is heated to reflux, hydrochloric acid is dropped, and reflux hydrolysis reaction is performed; the reaction solution is subjected to rotary evaporation, the remaining material is washed and dried to obtain D,L-methionine. The application adopts the mode of amino protection and removal, avoids the use of cyanide and high-temperature and high-pressure reaction, is safe and environment-friendly in the whole process, has high reaction selectivity, has few side reactions, and the by-products and the solvent are easy to separate, so that the cost is further reduced, and the industrialization popularization is facilitated.

This invention proposes a method for preparing selenomethionine, comprising the following steps: S1. Inoculating selenium-resistant Bacillus subtilis into a culture medium containing sodium selenite for activation, and selecting seed culture in the logarithmic growth phase; S2. Inoculating the seed culture into a fermentation medium, providing carbon and nitrogen sources for cell proliferation in the early stage of fermentation, and adding inorganic selenium source and exogenous methionine precursor in the middle and late stages of fermentation, while adjusting dissolved oxygen and pH to reduce inorganic selenium into selenomethionine within the cells; S3. After fermentation, subjecting the fermentation broth to cell disruption, solid-liquid separation, and drying to obtain a product rich in selenomethionine. This preparation method, through staged fermentation, balances cell growth and selenium conversion efficiency, achieving efficient synthesis of selenomethionine from Bacillus subtilis. The product contains selenium primarily in the form of selenomethionine, with a high proportion of organic selenium. The strains used are highly safe, the process is mature, and the application value is significantly improved, making it suitable for industrial-scale production.

The invention relates to the field of methionine preparation, in particular to a D, L-methionine crystal and a preparation method thereof.The preparation method comprises the steps that a methionine solution is cooled and crystallized in the presence of an additive, the D, L-methionine crystal is obtained, the additive comprises cocoyl amino acid salt and chitosan with the molecular weight ranging from 100,000 to 600,000, and the D, L-methionine crystal is obtained. The mass content of potassium bicarbonate in the methionine solution is less than or equal to 0.5%, and the concentration of methionine in the methionine solution is 7-14wt%. The crystal is high in purity, good in storage stability, high in hygroscopicity resistance, simple in preparation process, mild in condition, stable in quality and easy for large-scale industrial production.