47results about How to "Yield unchanged" patented technology

The invention discloses a method for using ionic liquid to promote intramolecular cross dehydrogenation coupling so as to synthesize benzothieno[3,2-b]chromone compounds. The method is characterized in that under a metal-free condition, water is used as solvent, the ionic liquid promotes the cross dehydrogenation coupling reaction of 3-aryloxybenzothiophene-2-aldehyde to effectively synthesize the benzothieno[3,2-b]chromone compounds, the reaction can be well performed under a gram-grade scale, and the activity of accelerator has no obvious declination after the accelerator is recycled for 5 times.

The invention provides a method for synthesizing a beta-amino-carbonyl compound by a pure water phase. Water is used as a reacting solvent, aldehydes, amines and ketones are used as raw materials, and salicylic acid or salicylic acid derivatives is or are adopted as a catalyst to react. The method opens a new low-cost, green and effective way to the preparation of beta-amino-carbonyl compounds, and has the advantages that a target product is good in selectivity and high in yield; the catalyst is small in dose and does not need to be separated from the solvent after the reaction is completed, and can be recycled directly in an aqueous solution manner; experiment results prove that the catalyst still has high catalytic activity after being recycled for 5 times, and the yield of the product is basically the same.

The invention provides a method for preparing a D-(+)-biotin intermediate. The method comprises the steps of: taking L-cysteine monohydrochloride as a starting material; using benzaldehyde and sodium cyanate as a ring closure reagent to synthesize (7aR)-3-phenyl-6-benzyl-1H, 3H-imidazo[1, 5-C]thiazole-(6H, 7aH)-5, 7-dione through the cyclization; then utilizing benzyl bromide to perform benzyl protection on N atoms; then taking zinc as a reducing agent to perform ring-opening synthesis on N, N-dibenzyl-L-sulfhydryl hydantoin; introducing a side chain through an esterification reaction with monomethyl adipate acyl chloride; and taking titanium as the reducing agent to perform reductive ring closure to generate the intermediate. According to the method, the cheap and readily available sodium cyanate is used as the ring closure reagent to replace sodium isocyanate which is toxic and difficult to purchase in an original method, reaction conditions are optimized and reaction order is adjusted, so the disadvantages of harsh reaction conditions and low yield in the original method of ring opening first and then benzyl protection are overcome by the method of performing benzyl protection on the N atoms of an imidazole part first and then performing ring opening; and the total yield reaches 34.0-38.0 percent.

The invention relates to a novel wet corn soaking method. The method comprises pulverizing de-embryonated corn to obtain powder of 20-40 meshes, adding water and a magnetic fullerene immobilized enzyme into the powder, carrying out stirring and soaking at 30-50 DEG C for 5-8 hours, recovering the magnetic fullerene immobilized enzyme through magnetic separation, transferring the remaining soakingmixture into a pulverizer, carrying out fine pulverization, sieving the powder through a sieve of 200 meshes, standing the filtrate over night, carrying out centrifugal separation and carrying out drying to obtain corn starch.

The invention relates to the technical field of catalytic materials, and in particular relates to a molybdenum-based catalyst, and a preparation method and application thereof. The preparation methodof the molybdenum-based catalyst comprises the following steps: adding a molybdenum source into an H2O2 / CH3CH2OH mixed solution, and carrying out stirring to form a reaction system; heating the reaction system to 50-70 DEG C, adding a protein assistant, continuously carrying out stirring, and then evaporating water and ethanol at a temperature of 80-100 DEG C to obtain a catalyst precursor; and filling the catalyst precursor under a nitrogen atmosphere, carrying out heating to 300-450 DEG C, then introducing mixed steam of lactic acid and water into the catalyst precursor, and reducing the catalyst precursor to prepare the molybdenum-based catalyst. The molybdenum-based catalyst prepared by the method is simple to prepare, and the catalyst is clean and non-toxic, is high in catalytic activity, good in stability and low in cost, and has a potential commercial development value.

The invention provides a method for preparing phenyl ethylbenzene ethane capacitor insulating oil through catalysis of acidic ionic liquid. The method is characterized in that 2-10mol of ethylbenzene reacts with 1mol of chlorine gas to generate a mixture of alpha-chloroethylbenzene and beta -chloroethylbenzene at 110 DEG C-150 DEG C through the ultraviolet irradiation or under the triggering action of a radical initiator, and the mixture generated through reaction is not separated and is directly mixed with a mixture of 5-20g of acidic ionic liquid catalyst and 2-10mol of ethylbenzene so as to react at 30-130 DEG C to prepare the phenyl ethylbenzene ethane. The phenyl ethylbenzene ethane capacitor insulating oil prepared by the method has excellent characteristics of normal temperature insulation oil, namely phenyl xylyl ethane; the condensation point of the phenyl ethylbenzene ethane capacitor insulating oil is far lower than that of the phenyl xylyl ethane; and the phenyl ethylbenzene ethane capacitor insulating oil has unique low-temperature-resistance performance and is particularly suitable for serving as low-temperature capacitor insulating oil.

The invention provides a method for improving resistance of a bacterial strain to inhibitors through micro aeration. The micro aeration is conducted, so the resistance of the bacterial strain to the various inhibitors (formic acid, acetic acid, furfural and hydroxymethylfurfural) in a cellulosic hydrolysate is improved, and the fermentation performance of glucose and xylose are significantly improved. Xylose fermentation conducted by using the method is compared with a control group without ventilation, the xylose has resistance to the various inhibitors in the cellulosic hydrolysate, under the conditions of four kinds of mixed inhibitors with relatively high concentrations, the fermentation time is shortened, residual xylose is decreased greatly and the yield of xylitol is improved. The fermentation of glucose and xylose mixed carbon sources by using the method is compared with a control group without ventilation, under the conditions of four kinds of mixed inhibitors with relatively high concentrations, the method promotes the simultaneous fermentation of glucose and xylose, the yield of ethyl alcohol remains unchanged, and the yield of xylitol is improved.

The invention discloses a preparation method of 7-methoxyflavone and belongs to the field of chemical synthesis. The preparation method comprises that paeonol and benzoyl chloride as raw materials undergo an esterification reaction in the presence of triethylamine base, then the reaction mixed solution is subjected to simple suction filtration so that triethylamine hydrochloride is removed, potassium tert-butoxide is directly added into the filtrate, the mixture undergoes a reaction at the normal temperature, dibutyltin oxide is added into the reaction product, and the formed reaction mixed solution is subjected to heating backflow dehydration so that 7-methoxyflavone is obtained. The technical route has the characteristics of less process, operation simpleness, no pollution, desiccant reuse and industrial production easiness. The preparation method is an economic and simple 7-methoxyflavone preparation method.