What is the preparation method of HMB-Ca (HMB-calcium).

The preparation method of HMB-Ca (HMB-calcium), abbreviated as HMB-Ca, belongs to the field of organic compound preparation technology. HMB-Ca (HMB-calcium) can promote animal muscle growth, enhance mammalian immunity, reduce human cholesterol and low-density lipoprotein (LDL) levels, reduce the occurrence of coronary heart disease and cardiovascular diseases, and also help to improve the body's nitrogen fixation ability and maintain protein levels in the body, so it is widely used.

At present, there are two main synthesis methods of HMB-Ca (HMB-calcium): 1. Free radical reaction, using tert-butanol as raw material, ferrous sulfate and hydrogen peroxide as free radical initiators, introducing CO gas into the aqueous solution of sulfuric acid, and then forming salt with CA(OH)2 to prepare HMB acid, and the generated free radicals can also be coupled to form coupling by-products. The results showed that the content of coupling by-products accounted for more than half of the total yield. In addition, the reaction requires an absolutely anaerobic operation, otherwise the radical chain reaction will be terminated and the reaction cannot continue. 2. Dioxane is the solvent, and the aqueous solution of NaClO is subjected to haloform reaction under strong alkali conditions and reflux temperature, and then acidified with sulfuric acid and extracted with ethyl acetate. After the solvent was removed, Na2SO4 was precipitated, purified water was added, and HMB acid was extracted with ethyl acetate. HMB acid reacts with Ca(OH)2 to obtain a crude HMB-Ca(HMB-calcium) with a yellow appearance.

The technical problem to be solved is to propose a simple method for the preparation of high-purity HMB-Ca. The technical problem was solved by the following technical scheme: 4-hydroxy-4-methyl-2-pentanone was used as the reaction raw material, water was used as the solvent, halogenation reaction occurred with naobr aqueous solution, acidification, isobutanol extraction, and HMB-Ca (HMB-calcium) in isobutanol was directly extracted with Ca(OH)2 salt.

The preparation method of HMB-Ca is characterized in that: 1. preparing naobr, dissolving 100 weight parts of NaOH in 400 weight parts of water, cooling to 0 °C in an ice salt bath, adding 192 weight parts of bromine under stirring, controlling the dropwise temperature at 0~5 °C, adding Naobr solution dropwise, and storing at 0~5 °C; 2. In the haloform reaction, the above solution is added to a mixed solution of 46.4 weight parts of 4-hydroxy-4-methyl-2-pentanone and 120 weight parts of water for 6 hours. After the reaction, 8 weight parts of NaHSO3 are added to fade and the lower bromoform is separated. The aqueous layer was adjusted to pH 2-3 with a 2mol/L HCl solution of about 120 weight parts, and then extracted with 150 weight parts of isobutanol 3-4 times to merge the isobutanol layers; 3. Add 120 parts of water to the isobutanol solution, and then add 14.8 parts Ca(OH)2. After stirring, the reaction was carried out at room temperature for 2 hours, the insoluble matter was filtered out, the filtrate was static stratified, the aqueous layer was separated, the white crystalline solid was obtained by evaporation under reduced pressure, and 27.2 parts of the product HMB-Ca (HMB-calcium) were dried to obtain a yield of 49.6%.