31 results about "Sulfuric Acid Dimethyl Ester" patented technology

An improved process for production and novel physical forms of butylated hydroxyanisole (BHA) is described wherein tertiary butyl hydroquinone (TBHQ) reacts within a range of about 30 to 50 DEG C with stoichiometrically slight excess of dimethyl sulphate and sodium hydroxide, the sodium hydroxide being added stoichiometrially in slight excess of dimethyl sulphate. Major portion of BHA formed in this reaction was recovered in a crystalline form in which 3-t-butyl-4-hydroxyanisole (3 isomer) is at least at about 99% level, usually at about 99.5% or more, and TBHQ at 100 ppm or less. BHA remaining in mother liquor after crystallization was recovered by distillation and had same purity as the crystalline BHA. The crystalline form was prepared as low density as well as high density form and further could be converted into compressed forms including flakes, tablets and the like.

The invention relates to a preparation method of metribuzin and a treatment method of waste liquid. The preparation method comprises the following steps: carrying out heat-insulation reaction on triazinone and dimethyl sulfate at 75 to 80 DEG C in the presence of p-xylene and concentrated sulfuric acid; after the reaction is finished, cooling to 60 DEG C or below; adding water and quenching the reaction; washing a p-xylene layer, distillating under the reduced pressure and drying to obtain the metribuzin. According to the preparation method provided by the invention, the triazinone, which is convenient to purchase in the market, is used as a raw material, the p-xylene is used as a solvent and the concentrated sulfuric acid is used as a catalyst; the metribuzin is prepared through a methodof dropwise adding the dimethyl sulfate; in the reaction process, few byproducts are produced and the treatment method is simple. In a wastewater treatment link, the p-xylene and water can be recycledand utilized and unreacted triazinone is easy to recycle and reutilize. The method provided by the invention has the advantages of high recycling rate, low cost and short production period and the prepared metribuzin has high purity and meets safety and environment protection requirements.

The invention discloses a method for synthesizing theophylline. The method comprises the following steps: performing a methylation reaction on dimethyl sulfate, 6-aminouracil and a sodium hydroxide solution; adding formic acid for a carboxylation reaction; adding a mixed acid solution formed by mixing fuming nitric acid and concentrated sulfuric acid at a volume ratio of (0.8-1.1):(0.9-1.2), and performing heating reflux for a nitrosylation reaction; and finally, adding iron powder and anhydrous acetic acid for a cyclization reaction to obtain theophylline. According to the method disclosed by the invention, the yield is greatly higher than that of the prior art, the operation process is simple, and the reaction conditions are simple.

The invention discloses L-leucine derivatives blocking the entrance of H5N1 avian influenza virus, which are 3,4-dyhydroxyl benzoyl leucine methyl ester and 3,4-dyhydroxyl phenylacetyl leucine methyl ester. The 3,4-dyhydroxyl benzoyl leucine methyl ester is prepared by condensing 3,4-dyhydroxyl benzoic acid with L-leucine methyl ester; the 3,4-dyhydroxyl phenylacetyl leucine methyl ester is prepared by taking 3,4-dyhydroxyl phenylacetic acid as a starting material, treating the 3,4-dyhydroxyl phenylacetic acid by virtue of dimethyl sulphate and thionyl chloride sequentially, then condensing the 3,4-dyhydroxyl phenylacetic acid with L-leucine methyl ester, and then performing demethylation reaction. The compounds, namely, the 3,4-dyhydroxyl benzoyl leucine methyl ester and the 3,4-dyhydroxyl phenylacetyl leucine methyl ester, disclosed by the invention, have a strong inhibitory activity on Influenza strain A / Vietnam / 1194 / 2004 avian influenza virus, and have a mechanism of acting on the entrance phase of H5N1 virus infected cells; and the compounds are a new inhibitor resisting the entrance of avian influenza virus, and can be used as a medicine for preventing or treating H5N1 avian influenza.

The invention discloses a method for preparing an indoline polymethin dye via a one-pot method. The method comprises the following steps of: carrying out condensation and ring closing on phenylhydrazine or para-substituted phenylhydrazine hydrochloride and methyl isopropyl ketone in an alcohol solvent under the catalysis of sulfuric acid so as to generate 2,3,3-trimethylindole or a derivative thereof, adding alkali to carry out neutralization, and carrying out filtration to remove salt; adding an appropriate acid-binding agent in the filtrate, dropwise adding dimethyl sulfate to generate 1,3,3-trimethyl-2--methylene indoline or a derivative thereof; and directly adding 1-phenyl-3-methyl-4-formyl-5-pyrazolone, and carrying out acid catalysis and condensation to generate a target dye. The method has the advantages of being easy to operate, high in yield, low in cost and less in wastewater.