43 results about "Dicyclohexylurea" patented technology

The invention discloses a synthetic method of a dicyclohexylcarbodiimide compound. The method comprises the following steps: taking dicyclohexylurea and di(trichloromethyl) carbonate as a raw material, fully reacting in an organic solvent A at the temperature of 20-110 DEG C, cooling to the room temperature after finishing the reaction, adding triethylamine and neutralizing to pH value of 7-8, post-treating a reaction solution to prepare the dicyclohexylcarbodiimide compound; wherein the organic solvent A is C1-C5 haloalkanes, C3-C8 fatty ester, ketones, ethers, benzene, toluene, xylene, chlorobenzene, nitrobenzene, cyclohexane or nitromethane. The method basically eliminates the problems of big hidden trouble of traditional technical safety and serious three wastes pollution. The method for synthesizing dicyclohexylcarbodiimide compound has the advantages of safety, reliability, simple process, less three wastes, small energy consumption, high overall yield, low cost and excellent product quality, and is suitable for industrialization production and has good economic benefit.

The invention discloses a method to prepare N,N`-dicyclohexylurea. The method takes carbamide and cyclohexane as material and water as solvent; a stirring device, a heating device, a reflux device and a water separating apparatus are arranged inside a reactor; the mixture is stirred and heated to flow back and the phegma flows into the water segregator; the azeotropic liquid in the water segregator is gradually discharged; with the reduction of the water, the temperature of the reaction gradually rises and when the temperature rises to 180-240 DEG C, the reaction will be continued for 10-30 min at this temperature, producing N,N`-dicyclohexylurea. The method greatly shortens preparation period with a yield over 95%, and meanwhile the method requires no organic solvent.

The invention belongs to the technical field of fine chemical engineering and in particular relates to a preparation method of dicyclohexylcarbodiimide. The preparation method comprises the followingsteps: dissolving chloroacetyl chloride in a solvent to obtain a solution A; stirring dicyclohexylurea, a catalyst and a solvent uniformly to obtain a solution B; dropwise adding the solution A into the solution B at a certain temperature; then carrying out an insulating reaction; after the reaction, adding a pH regulator to regulate the solution to be neutral; carrying out suction filtration on the reaction solution; distilling the filtrate at constant pressure to remove the solvent; and then carrying out distillation at a reduced pressure to obtain dicyclohexylcarbodiimide. The preparation method of dicyclohexylcarbodiimide is simple in process, the reaction stability and the product yield are improved greatly, dicyclohexylcarbodiimide can be produced industrially on a large scale, and the preparation method has the advantages of being simple and feasible and simple to operate.

The invention discloses a preparation method of N,N'-dicyclohexyl urea, which is characterized in that: anionic functionalized ionic liquid absorbs CO through chemical action ₂ In situ reaction of carbon source and cyclohexylamine, N,N'-dicyclohexylurea was prepared under mild conditions. with traditional CO ₂ Compared with the method of preparing N,N'-dicyclohexyl urea directly with cyclohexylamine reaction, this method has the advantages of low reaction temperature and pressure, CO ₂ The utilization rate is high, the anionic functionalized ionic liquid can be recycled, and no additional catalyst, dehydrating agent and solvent are needed. It is a preparation method of N,N'-dicyclohexyl urea with industrial application potential.

The invention relates to a method for recycling recycled N,N'-dicyclohexylurea. The method comprises the steps of adding N,N'-dicyclohexylurea and sodium hydroxide into a reaction still, starting stirring, raising temperature to 80-450 DEG C and reacting for 2-8 hours to steam out yielded fluid of cyclohexane in a reaction process. The method has the advantages that the N,N'-dicyclohexylurea of a bio-polypeptide condensing agent by-product is recycled to achieve reclamation of wastes, the problem that the industrialization of the N,N'-dicyclohexylurea is hard to be processed is solved, and the regeneration from the N,N'-dicyclohexylurea to cyclohexylamine to N,N'-dicyclohexylcarbodiimide is achieved, a solvent is not used, and the shortcomings that an organic solvent is flammable and combustible and high in cost are overcome, the yield of the cyclohexylamine is larger than 99%, the purity is larger than 99.3%, raw materials only have the N,N'-dicyclohexylurea and the sodium hydroxide, the products are only cyclohexylamine and sodium carbonate, and the cyclohexylamine and the sodium carbonate can be separated easily. The method is safe and environmentally friendly, low in cost and suitable for industrial production.

The invention provides a preparation method of roflumilast. The preparation method of roflumilast comprises the following steps of : (1) taking 3-cyclopropyl methoxy group-4-difluoro methoxy group benzoic acid and 4-amino-3, 5-dichloropyridine, and adopting N, N'-dicyclohexylcarbodiimide as the catalytic agent to perform amide reaction, wherein mole dosage ratio of 4-amino-3, 5-dichloropyridine and 3-cyclopropyl methoxy group-4-difluoro methoxy group benzoic acid is equal or greater than 1; mole dosage ratio of N'-dicyclohexylcarbodiimide and 4-amino-3, 5-dichloropyridine is equal or greater than 1, and solvent used by the amide reaction is aprotic polar solvent; and (2) after the reaction is finished, adding poor solvent of N, N'-dicyclohexylurea to perform purification, and accordingly roflumilast refined products are obtained. The preparation method of roflumilast adopts DCC (N, N'-dicyclohexylcarbodiimide) as the catalytic agent, guarantees good product yield and purity, can directly perform amidate condensation reaction without performing acylating chlorination reaction on intermediates, simplifies reaction steps, simultaneously avoids corrosivity from acylating chlorination solvent thionyl chloride to equipment, and is more suitable for industrialized mass production.

The invention discloses a method for preparing dicyclohexylcarbodiimide by using a vilsmeier reagent. The method comprises the following steps: preparing a vilsmeier reagent by using N, N-dimethylformamide (DMF) and thionyl chloride (SOCl2), reacting the vilsmeier reagent with dicyclohexylurea (DCU), and carrying out aftertreatment to obtain the dicyclohexylcarbodiimide. According to the method, the vilsmeier reagent is adopted, the reaction can be carried out under mild conditions, the process is safe and stable, and the method is suitable for industrial large-scale production.

The invention discloses a method for synthesizing cyclohexyl carbamate. The invention chooses a supported metal oxide solid catalyst to catalyze dialkyl carbonate and N,N'-dicyclohexylurea to obtain the product. The method is mainly characterized in that reaction condition is relatively mild; the catalyst is easy to recycle and good in repeated use; the reaction is atom economy; and the separatedproduct has high purity.

The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing N,N'-dicyclohexyl carbodiimide through a microwave-assisted method. The method comprises the following steps: dissolving N,N'-dicyclohexyl urea in a solvent under microwave radiation, adding an oxidant and a catalyst loaded on a molecular sieve, and carrying out heat preservation reflux; adding a phase transfer catalyst, adjusting the pH value, and carrying out alkaline hydrolysis reaction; filtering, separating liquid, evaporating out the solvent, and carrying out reduced pressure distillation to obtain N,N'-dicyclohexyl carbodiimide. The catalyst loaded on the molecular sieve is large in specific surface area and high in catalytic efficiency; a microwave-assisted method is adopted, and a phase transfer catalyst is added, so that the problems of difficult two-phase reaction and incomplete reaction in the traditional process are solved, the reaction conversion rate is greatly improved, the reaction time is shortened, and the product has the characteristics of high purity and yield.

The invention relates to pidotimod, in particular to a process for removing pidotimod condensation impurities. The process for removing the pidotimod condensation impurities includes the step of preparing dichloromethane mother liquor containing dicyclohexylurea in a process for preparing pidotimod. According to the process for preparing pidotimod, dicyclohexyl carbodiimide serves as a condensingagent, the dichloromethane mother liquor containing dicyclohexylurea is subjected to hydrolysis and skimming, a water phase is obtained, the water phase is treated through a macroporous resin filler column, salification is achieved after the water phase is treated, and pidotimod is obtained after refining is carried out. The dichloromethane mother liquor containing dicyclohexylurea is subjected tohydrolysis and skimming, the water phase is obtained, the water phase is treated through the macroporous resin filler column, and the impurities, namely dicyclohexylurea, in pidotimod products are completely removed. The defect that the impurities, namely dicyclohexylurea cannot be completely removed through an existing process is overcome, and the method which is simple, effective, safe, environmentally friendly and suitable for industralization is found.

The invention discloses a preparation method to recycle pyribenzoxim byproduct dicyclohexylurea and belongs to the field of agricultural chemistry. The byproduct N,N'-dicyclohexylurea is used as a rawmaterial; N,N'-dicyclohexylurea and organic phosphorus catalyst are heated to 140-160 for reacting; the temperature is then lowered to 60-80 DEG C for reacting; after reacting, the catalyst is recycled by filtering, and filtrate is distilled under reduced pressure; distillate at 125-140 DEG C (6-8 mmHg) is collected and cooled to obtain white solid, N,N'-dicyclohexylcarbodiimide; the highest yield reaches 88.2%, and purity reaches 98.4%. The preparation method is efficient, environmentally friendly, sustainable, and suitable for industrial production; the preparation method has the advantagesof good energy efficiency, low consumption, lower pollutant emission and the like, allows a preparation technique of recycling byproducts of pyribenzoxim production process to be implemented, and meets the green manufacturing principle.

The invention belongs to the field of chemical detection, and discloses a detection method of N,N'-dicyclohexylurea and N,N'-dicyclohexylcarbodiimide. The detection method comprises the following steps: dissolving a sample with methanol; diluting with acetone; filtering with an organic filter membrane; and detecting with a gas chromatograph-mass spectrometer. The method has the advantages of highseparation degree, symmetrical peak pattern and relatively higher accuracy and precision, and fills up the technical blank of the simultaneous qualitative and quantitative detection of the N,N'-dicyclohexylurea and the N,N'-dicyclohexylcarbodiimide.

The invention relates to a preparation method for two peptides, in particular to the preparation method for benzyloxycarbonyl alanyl alanine, and mainly solves the technical problem that the conventional synthetic method is not suitable for industrial production. The invention adopts the following technical scheme: the preparation method comprises the steps as follows: 1, adding L-alanine methyl ester hydrochloride into dichloromethane, adding organic alkali and benzyloxycarbonyl alanine, carrying out ice-bath treatment, dropwise adding a dichloromethane solution of N,N'-dicyclohexyl carbodiimide, reacting overnight, filtering out dicyclohexylurea, rotationally steaming to remove dichloromethane, carrying out conventional treatment to obtain a white solid, and re-crystallizing to obtain benzyloxycarbonyl alanyl alanine methyl ester; and 2, dissolving benzyloxycarbonyl alanyl alanine methyl ester in alcohol, adding a sodium hydroxide solution for saponification reaction, and carrying out conventional treatment to obtain benzyloxycarbonyl alanyl alanine as a final product.

The invention relates to the field of a medicine synthesis technology, and in particular relates to a preparation method of carbamazepine (CBZ)-valaciclovir. The preparation method comprises the steps of: reacting CBZ-L-valine with an acyl chlorination reagent to obtain acyl chloride; then, reacting acyl chloride with a mixed system of acyclovir and an acid-binding agent; and finally, filtering and refining to obtain the CBZ-valaciclovir. According to the method, acyl chloride is utilized to prepare ester, dicyclohexylcarbodiimide (DCC) is not used in the reaction process and does not generate dicyclohexylurea (DCU) is not remianed in the product, thus being beneficial to improvement of the palladium-carbon utilization rate; and the preparation method disclosed by the invention is an effective method for preparing the high-purity CBZ-valaciclovir.