| ?-Hydroxy-?-methylbutyric acid is an intermediate metabolite of leucine,which is widely present in citrus fruits,certain vegetables and certain fish and seafood.?-Hydroxy-?-methylbutyric acid has the functions of promoting protein synthesis,inhibiting protein degradation,improving livestock and poultry production performance,improving carcass traits,enhancing immune function,reducing disease incidence and mortality.As a new anabolic nutrient for high-intensity exercisers,?-hydroxy-?-methylbutyric acid can reduce body fat,reduce muscle protein consumption,help muscle recovery and reduce muscle damage caused by overwork,which can increase exercise intensity and endurance.?-Hydroxy-?-methylbutyric acid is also a strong immune stimulant,which can enhance the body's immune function,lower blood cholesterol,reduce disease,prevent aging,enhance physical fitness,and improve quality of life.?-Hydroxy-?-methylbutyric acid was mainly used in animal feeding at first,and was later widely used in sports and fitness,medicine and food industries.Due to the active nature of?-hydroxy-?-methylbutyric acid,in order to facilitate storage and use,it is usually converted into calcium ?-hydroxy-?-methylbutyrate.Calcium ?-hydroxy-?-methylbutyrate is a white powder with a slightly irritating taste,good fluidity,easy to dissolve in water,the aqueous solution is weakly alkaline,and the aqueous solution has an insignificant bitter taste.This subject mainly adopts two schemes to synthesize ?-hydroxy-?-methylbutyric acid.Scheme one uses ethyl bromoacetate and acetone as raw materials,and tetrahydrofuran as a solvent,synthesis of ?-hydroxy-?-methylbutyrate ethyl ester by reformatsky reaction,then hydrolyzed to ?-hydroxy-?-methylbutyric acid.In the experiment,the influence of factors such as the order of addition of the solvent required for the reaction,the drop rate of ethyl bromoacetate,the reaction temperature,and the reaction time on the product was mainly investigated,and the experimental scheme was optimized.Experiments show that when the molar ratio of acetone to ethyl bromoacetate is 2:1,12 times the amount of tetrahydrofuran added,the amount of magnesium filings is 1.05 times,the reaction temperature is 60?,the reaction time is 20 h,speed is 1200 r/min,the yield of ?-hydroxy-?-methyl ethyl ester is 53%.Hydrolyze the crude ?-hydroxy-?-methyl ethyl ester,ethyl acetate extraction,the product?-hydroxy-?-methylbutyric acid is obtained.Detection and analysis by Angilent6820 gas chromatograph.Scheme two uses diacetone alcohol and sodium hypochlorite as raw materials,synthesis of ?-hydroxy-?-methylbutyric acid by haloform reaction,then purified into salt.The effect of the molar ratio of available chlorine to diacetone alcohol in sodium hypochlorite solution and the reaction temperature on the conversion of diacetone alcohol and the effect ofacidity on the yield of ?-hydroxy-?-methylbutyric acid were investigated,and use internal standard method for quantitative analysis and response surface analysis.The conclusion is that the molar ratio of available chlorine to diacetone alcohol is 3.75:1,the reaction temperature was15?,the reaction time was 2 h,and the p H value after acidification with hydrochloric acid was2,the conversion rate of diacetone alcohol was calculated to be 64.1 %.In the course of the research,using gas chromatography to quantitatively analyze ?-hydroxy-?-methylbutyric acid,and verify the linear relationship of the method,the standard curve fitting degree drawn is 0.9996,which can be used to analyze the data,and the method The precision is good. |
PDF Full Text Request