342 results about "P-toluenesulfonate" patented technology

The invention discloses a method for continuously preparing regenerated cellulose fibers through the solvent method, comprising the following steps that: a cellulose raw material is dissolved into an ion liquid to prepare a spinning liquid; gel type regenerated cellulose fibers are obtained through spinning; and the regenerated cellulose fibers are obtained through cleaning, rear draft and drying, wherein, the ion liquid is selected from one or a plurality among the following ion liquids: a). an ion liquid with 1, 3-dialkyl imidazole as a cation and formiate radical, radical vinegar or propionate radical as an anion; and b). an ion liquid with 1-R1-3-R2- dialkyl imidazole as the cation and chlorine, bromine, iodine, formiate radical, radical vinegar, sulfate radical, nitrate radical, tetrafluoroborate radical, thiocyanate radical, hexafluorophosphate radical, p-toluenesulfonate radical or trifluoromethanesulfonic acid radical as the anion. The method has the advantages of wide technological range, mild temperature condition, adequate pressure, quick spinning speed and so on, can prepare the regenerated cellulose fibers with superior performance and complete specifications, and has low production cost, high production efficiency and wide application prospect.

The invention discloses a preparation method of a layered nano-mordenite molecular sieve. A template used by the method is hexadecyltrimethylammonium p-toluenesulfonate. The method specifically comprises the steps of: first dissolving a silica source in an alkaline solution which contains different aluminium sources, and carrying out isothermal stirring; then adding the solution dropwise in an aqueous solution which contains the template, continuing to carry out stirring, and transferring the solution to an enclosed reactor for crystallization after the solution cools to room temperature; after carrying out filtering and washing as well as drying on a crystallization product, finally carrying out roasting to obtain the layered nano-mordenite molecular sieve. The method of the invention uses the hexadecyltrimethylammonium p-toluenesulfonate as the template, thereby greatly reducing the use amount of a synthetic system surface active agent. The prepared layered nano-mordenite molecular sieve has a high degree of crystallization, high purity, and abundant secondary accumulation pores, and therefore the method of the invention is an environmentally friendly synthetic method.

The invention discloses a preparation method of a ribofuranose phosphate derivative. The preparation method comprises preparation steps as follows: L-alanine isopropyl ester hydrochloride, phenol dichlorophosphate and substituted phenol are taken as starting materials and have a docking reaction under the action of alkali; (2R)-2-deoxy-2-difluoro-2-methyl-D-erythropentonic acid GAMMA-lactone and 3,5-dibenzoate reduce carbonyl in a dichloromethane or ether solvent into an alcoholic hydroxyl group under the action of a strong reducing agent; an intermediate with a formula 2-1 has a reaction with paratoluensulfonyl chloride under the action of alkali to obtain p-toluenesulfonates; an intermediate with a formula 2-2 and a benzoyl cytosine derivative have a docking reaction under the action of a condensing agent; an intermediate with a formula 2-3 converts cytosine into uracil under the action of organic acid; benzoyl protection for an intermediate with a formula 2-4 is released under the action of an alkaline agent; an intermediate with a formula 2-5 and an intermediate with a formula 1 are docked under the action of a Grignard reagent to obtain Sofosbuvir.

A method for improving the strength of carbon fibers, comprising: 1) soaking the carbon fibers in an aqueous solution of nitric acid, washing the carbon fibers with deionized water until the washing liquid is neutral after soaking; 2) preparing a carbon nanotube dispersion into a spraying liquid, carbon The nanotubes are functionalized carbon nanotubes, which are obtained from hydroxylated carbon nanotubes, carboxylated carbon nanotubes or aminated carbon nanotubes. The dispersion liquid is a mixture of ionic liquid and water, and the ionic liquid is obtained from 1,3 -Dimethylimidazole p-toluenesulfonate, 1-butyl-3-methylimidazole p-toluenesulfonate, 1-octyl-3-methylimidazole chloride or 5-bromo-2-methyl-3 - One of the nitropyridines, the content of carbon nanotubes in the spraying liquid is 16-48g / L; 3) The spraying liquid is applied with positive static electricity of 10-40kV, and the carbon fiber tow is flattened and grounded to form a spraying liquid acceptor, and then passes through Electrostatic spraying sprays the spray liquid on the carbon fiber surface. The tensile strength of carbon fiber can be increased by more than 100%.

A carbon fiber reinforcement method, which uses electrostatic spraying to coat carbon nanotubes on the surface of carbon fibers to compensate for surface structural defects and increase its strength, including: preparing a spraying liquid with a dispersion of carbon nanotubes, and the carbon nanotubes are derived from hydroxyl One of carbon nanotubes, carboxylated carbon nanotubes or aminated carbon nanotubes, the dispersion liquid is a mixture of ionic liquid and water, and the ionic liquid is obtained from 1,3-dimethylimidazole p-toluenesulfonate, 1 - One of butyl-3-methylimidazole p-toluenesulfonate, 1-octyl-3-methylimidazole chloride, or 5-bromo-2-methyl-3-nitropyridine; spray application 10-40kV positive electrode static electricity, the carbon fiber tow is flat and grounded to form a spray liquid receiver; the spray liquid is sprayed on the surface of the carbon fiber by electrostatic spraying, and the spraying amount is 1000: (0.4-10 based on the weight ratio of carbon fiber to carbon nanotube ). After repairing, the tensile strength of carbon fiber can be increased by more than 100%.

The invention discloses a 4-(4-dimethylaminostyryl)methylpyridine p-toluenesulfonate (DAST)-carbon nano tube composite film and a preparation method thereof. The film is formed by compounding a carbon nano tube and a DAST film. According to the invention, the DAST-carbon nano tube composite film is used for manufacturing the devices such as infrared or terahertz photoelectric detector, temperature sensor and gas sensor, the shortcomings of the pure carbon nano tube or pure DAST material in the performance of electrics, optics and the like can be overcome, and the comprehensive performance of the device is improved. The preparation method of the DAST-carbon nano tube composite film disclosed by the invention does not need complicated and expensive film forming equipment, reduces the manufacturing cost, improves the working performance of the device, and is suitable for large-scale industrial production.

A square solid-state capacitor comprises a square aluminum shell, a capacitor core pack, a rubber plug and an aluminum shell cover plate, wherein the capacitor core pack is of a flat oval shape, the rubber plug and the aluminum shell cover plate are used for sealing the core pack in the square aluminum shell, the capacitor core pack comprises a positive electrode foil, a negative electrode foil, a piece of electrolytic paper, a positive lead and a negative lead, the electrolytic paper, the positive lead and the negative lead are arranged between the positive electrode foil and the negative electrode foil, a monomer and an oxidizing agent are immersed in the electrolytic paper, a conductive polymer is generated on the electrolytic paper from the monomer and the oxidizing agent, the monomer is one or more EDOT and derivatives thereof, pyrrole and aniline, and the oxidizing agent is one or more of iron p-toluenesulfonate, ammonium persulfate, sodium persulfate, ammonium sulfate and ferric chloride. The solid-state capacitor with a square structure is small in thickness (width) and long in length, the volume, capacity and density requirements of the solid-state capacitor are ensured, meanwhile, the demand for placing the solid-state capacitor in a flat space is met, and the space utilization ratio and the cooling performance of the capacitor are improved.

The invention discloses a preparation method of polypyrrole-coated lithium iron phosphate. The preparation method comprises the following steps: dissolving iron(III) p-toluenesulfonate hexahydrate in alcohol; ultrasonically dispersing lithium iron phosphate powder in the alcohol; placing into a sealed container; adding pyrrole monomers under low-temperature stirring condition; stirring for a period of time, so that the pyrrole monomers generate polymerization reaction on the surface of lithium iron phosphate; filtering; washing; drying; grinding; and sieving to obtain polypyrrole-coated lithium iron phosphate. The polypyrrole-coated lithium iron phosphate prepared by the method can be assembled with lithium tabs to form a test battery, which has an reversible capacity of 115 mAh / g during charge / discharge at 20C rate and an initial specific capacity of 155 mAh / g during charge / discharge cycle at 55 DEG C and 5C rate and can keep the specific capacity at 90% the initial value after 300 cycles. Accordingly, the test battery exhibits excellent high-rate charge / discharge capability and good high-temperature cycle stability. The method is simple and feasible, and suits large-scale industrial production.

The invention relates to a synthesis process for a spice, in particular to a synthesis process for cyclohexyl acetate. The invention provides the synthesis process for the cyclohexyl acetate with simple operation, low pollution and high yield. The process comprises the steps of synthesis of copper p-toluenesulfonate and synthesis of the cyclohexyl acetate.

The invention discloses a method for catalytic synthesis of methyl propionate. The method comprises the steps of: uniformly mixing a catalyst and propanoic acid, adding to a reaction kettle, heating the reaction kettle in an oil bath, after the liquid in the kettle reaches a certain temperature, continuously adding a mixture of propanoic acid and methanol, beginning an esterification reaction, and rectifying with a rectifying tower to obtain methyl propionate, wherein the catalyst is selected from an ion liquid of pyridinium hydrogen sulfate, imidazolium hydrogen sulfate, pyridinium p-toluenesulfonate, imidazolium p-toluenesulfonate and imidazolium hydrogen phosphate or p-toluenesulfonic acid. The method has the advantages that the equipment corrosion caused by strong acidity when sulfuric acid is used as the catalyst is avoided, the industrial investment cost is lowered, the utilization rate of the catalyst is higher, and the yield of the esterification reaction can reach more than 93%.

The invention relates to an immobilized ionic liquid catalyst and application thereof. The immobilized ionic liquid catalyst has a general structural formula as defined in the specification. In the general structural formula, P is a nanogel resin matrix; n is an integer in a range of 2 to 12; and M<-> is a negative ion selected from a group consisting of a trifluoromethanesulfonate group, a p-toluenesulfonate group, a benzenesulfonate group, a methanesulfonate group, a tetrafluoroborate group and a hexafluorophosphate group. The immobilized ionic liquid catalyst can be applied to industrial olefine acid addition for preparation of corresponding esters.

A method for improving the strength of carbon fibers, which uses an electrostatic spraying method to coat carbon nanotubes on the surface of carbon fibers to make up for their surface structural defects, comprising: preparing a dispersion liquid for carbon nanotubes into a spraying liquid, and the dispersion liquid is a mixture of ionic liquid and water , the ionic liquid is taken from 1,3-dimethylimidazole-p-toluenesulfonate, 1-butyl-3-methylimidazole-p-toluenesulfonate, 1-octyl-3-methylimidazole chloride or 5- One of bromo-2-methyl-3-nitropyridine; the spray liquid is applied with 10-40kV positive static electricity, and the carbon fiber tow is flat and grounded to form a spray liquid receiver; the spray liquid is sprayed on the surface of the carbon fiber by electrostatic spraying, Based on the weight ratio of carbon fibers to carbon nanotubes, the spraying amount is controlled to be 1000:(0.5-10). The invention has the advantages of simple process, low cost, high efficiency, good repairing effect of carbon fiber surface structural defects and the like, and is easy to realize industrial application.

The invention relates to an immobilized ionic liquid catalyst and application thereof. The immobilized ionic liquid catalyst has a general structural formula as defined in the specification. In the general structural formula, P is a nanometer macroporous resin matrix; n is an integer in a range of 2 to 12; M<-> is a negative ion selected from a group consisting of a trifluoromethanesulfonate group, a p-toluenesulfonate group, a benzenesulfonate group, a methanesulfonate group, a tetrafluoroborate group and a hexafluorophosphate group; and the nanometer macroporous resin matrix is a nanometer macroporous copolymer prepared from styrene monomer, copolymerization monomer, a graphene material and a pore-forming agent through in-situ copolymerization. The immobilized ionic liquid catalyst can be applied to industrial olefine acid addition for preparation of corresponding esters.

The invention belongs to the technical field of single crystal wafer tools and especially relates to a single crystal wafer texturing additive. The single crystal wafer texturing additive is characterized by comprising the following components in parts by weight: 0.01-1% of fluorocarbon surfactants, 1-5% of polyvinylpyrrolidone, 0.1-3% of crylic acid-maleic anhydride copolymer, 1-5% of propylene glycol monomethyl ether, 0.05-0.5% of sodium benzoate, 0.1-2% of sodium p-toluenesulfonate and the balance of water. The single crystal wafer texturing additive has the beneficial effects of excellent texturing effect, smaller size of flock pyramid after texturing, narrower distribution, capability of reducing light reflection and capability of increasing photoelectric conversion efficiency of an assembled solar cell.

The invention provides a p-cresol preparation method and equipment. The method comprises the following steps that toluene and sulphuric acid take a reaction to obtain paratoluenesulfonic acid; the paratoluenesulfonic acid then takes a reaction with sodium sulfite to obtain sodium p-toluenesulfonate; the sodium p-toluenesulfonate generates sodium p-cresol under the alkaline condition; the p-cresol is generated by the sodium p-cresol under the alkaline condition. The method and the equipment can thoroughly solve the problem that in the current p-cresol production process, a great amount of waste water, waste gas and waste slag are generated; the automation level of the equipment is improved; most intermittent production is changed into continuous production; the work environment is improved.

This invention concerns a method for increasing the polymerization rate of polyester polymers in the solid state by adding a catalytic amount of zinc p-toluenesulfonate to a polyester polymer melt that is essentially free of antimony and germanium, before solid state polymerization.

The invention relates to a method for detecting genotoxic impurities in an AL58805 bulk drug or medicinal preparation by using high-performance liquid chromatography. The method is directed at methyl p-toluenesulfonate (MPTS) and ethyl p-toluenesulfonate (EPTS); a sample undergoes pre-treatment at first; and then high-performance liquid chromatography is employed for determination, wherein a C18 chromatographic column is employed; detection wavelength is 225 nm; an aqueous acetonitrile-phosphoric acid solution is used as a mobile phase; flow velocity is 0.8 to 1.2 mL / min; column temperature is 30 to 40 DEG C; a sample size is 20 [mu]L; and elution time is 18 min. Results show that the detection limit of MPTS is 0.3 ppm and the limit of quantitation of MPTS is 1 ppm; and the detection limit of EPTS is 0.5 ppm and the limit of quantitation of EPTS is 1.4 ppm. The method has the advantages of good specificity, simple operation, high sensitivity and accurate results and is applicable to determination of MPTS and EPTS in AL58805.

The invention relates to a preparation method for a Sacubitril intermediate. The preparation method comprises the following steps that (3R,5S)-5-(hydroxymethyl)-3-methyl-2-pyrrolidone is esterified with toluene sulfochloride or methanesulfonyl chloride to obtain (3R,5S)-5-(methyl p-toluenesulfonate)-3-methyl-2-pyrrolidinone or (3R,5S)-5-(methyl methanesulfonate)-3-methyl-2-pyrrolidinone; (3R,5S)-5-(methyl p-toluenesulfonate)-3-methyl-2-pyrrolidinone or (3R,5S)-5-(methyl methanesulfonate)-3-methyl-2-pyrrolidinone is coupled with 4-diphenylmagnesium bromide or 4-diphenylmagnesium chloride to obtain (3R,5S)-3-methyl-5-(1,1'-diphenyl-4-yl-methyl)-2-pyrrolidinone. According to the preparation method, the method is novel, the raw materials are easy to obtain, the technology is simple, and the purity and yield of the product are both very high.

The invention discloses a method for preparing iron p-toluenesulfonate and a solution thereof. The method for preparing the iron p-toluenesulfonate includes the steps that (1) a sodium hydroxide solution and an ammonium ferric sulfate solution are prepared; (2) the sodium hydroxide solution is added in the ammonium ferric sulfate solution, the final potential of hydrogen (pH) value of reaction is 7.0 to 9.0, and iron hydroxide precipitation is obtained; (3) the iron hydroxide precipitation is washed, placed in a filter bag and suspended to be dried at room temperature until the iron hydroxide precipitation which is colloid and contains a small amount of water is formed; (4) iron hydroxide which is suspended to be dried is reacted with a p-toluene sulfonic acid to generate an iron p-toluenesulfonate solution; (5) the iron p-toluenesulfonate solution is filtered and concentrated to be viscous, and discharging-cooling and crystallization are performed; and (6) crystals are crushed and dried to obtain the product. The method for preparing the iron p-toluenesulfonate and the solution thereof has the advantages that the activity of the reaction intermediate iron hydroxide is good, the reaction with the p-toluene sulfonic acid is complete, the process is simple, the energy consumption and the cost are low, and the environmental pollution is small.

The invention discloses a lead-acid storage battery repairing liquid and a method for repairing the lead-acid storage battery by using the same, belongs to the field of the lead-acid storage battery, and solves the problems that a failure lead-acid storage battery caused by salinization is difficult to repair. The lead-acid storage battery repairing liquid comprises a catalytic complexing agent, a surfactant, a bulking agent, a sulfate additive and sodium p-toluenesulfonate. The method for repairing the lead-acid storage battery comprises the steps of (1) putting the storage battery in a container, injecting water to the container until a water level is flush with a middle cover of the storage battery, adjusting water temperature and charging the storage battery; (2) subjecting the storage battery to horizontal and vertical frequency wave vibration, taking out the storage battery and injecting the lead-acid storage battery repairing liquid; (3) connecting storage batteries with open circuit voltage differential voltage smaller than 0.3 V into a group in series; (4) charging for a plurality of times in different current, discharging at 2H rate and then charging for a plurality of times in different current; and (5) discharging redundant lead-acid storage battery repairing liquid. The horizontal and vertical frequency wave vibration allows lead sulfate to be smashed; the lead-acid storage battery repairing liquid allows the electrical conductivity of the storage battery to be enhanced and the internal resistance of the storage battery to be reduced; and the capacity of the lead-acid storage battery can be repaired to over 95% that of an original storage battery.

The invention provides a non-linear optical crystal 4-[4-(dimethylamino)styryl]-methylpyridine . p-toluenesulfonate and a preparation method and applications thereof, and belongs to the field of functional materials. The molecular formula of the crystal is C22H23ClN2O3S, the crystal belongs to monoclinic crystal system, Cc space group, the lattice parameters are as follows: a equals to 10.363 (5), b equals to 11.163 (5), c equals to 17.892 (6) angstrom, beta equals to 92.15 (3) degree, Z equals to 4, and V equals to 2068.2 (15) angstrom<3>; the non-linear optical frequency-doubled effect of the crystal is 1.3 times of that of DAST, the time-domain spectral signal strength generated by the device made of the crystal is equal to that of DAST crystal in the wavelength range of 1.5 to 8.2 THz, the terahertz-wave radiation intensity is 1.05 times that of DAST crystal, and the parameters mentioned above have shown that the crystal is an excellent terahertz radiation source material.

The invention discloses a preparation method of an organic anion pillared rare earth hydroxide nanosheet sol, the composition of the nanosheet sol is {Y1.9Eu0.05(OH)5(+)}-A, wherein A is benzoic acid radical, p-toluenesulfonic acid radical or dodecyl sulfate radical, the method takes yttrium nitrate hexahydrate, europium nitrate hexahydrate and sodium benzoate, sodium P toluenesulfonate or sodium dodecyl sulfate as raw materials, a hydro-thermal synthetic method is used for synthesizing a layered material of Y1.9Eu0.1(OH)5[A].2H2O; the layered material is treated by ultrasound in a n-butyl alcohol solvent to obtain the nanosheet sol which is peeled to a flaky state. The preparation method is simple and is environment friendly.

The invention relates to a device and method for processing sodium p-toluenesulfonate waste liquor. The device comprises a direct current power supply, a membrane stack, a clamping device, a carbon fiber felt electrode, an electrode liquor storage tank, an acid chamber storage tank, a waste liquor chamber storage tank, an alkali chamber storage tank, a liquor adjuster, an alkali chamber valve block, a waste liquor chamber valve block, an acid chamber valve block, an electrode chamber valve block, an acid chamber filled with a cation exchange resin, a salt chamber, an alkali chamber filled with an anion exchange resin, an anion exchange membrane, a cation exchange membrane and a bipolar membrane. A PAN (polyacrylonitrile)-based carbon fiber felt electrode used in the device and method has the characteristics of low resistance, good electric conductivity, oxidation resistance and corrosion resistance. The salt chamber is filled with a cation and anion mixed resin, and the acid chamber and the alkali chamber are respectively filled with the cation exchange resin and the anion exchange resin, so as to further improve the conductance of an electrodialysis cell, reduce the polarization and energy consumption, and lighten the membrane pollution. The device and method can be used for processing the production waste liquor of high-concentration hardly-degradable pentaerythritol triacrylate, so as to obtain acid and / or alkali and realize recycling of the waste liquor.

A synthesis method of fatty acid isopropyl belongs to the ester compound synthesis technical field of organic chemistry, which uses fatty acid and isopropyl alcohol as raw materials. The invention is characterized in that in the presence of organic acid catalyst, the invention processes reflux reaction to give fatty acid isopropyl crude produce, distills abundant isopropyl alcohol, neutralizes via alkali, washes via water and dewaters in vacuum to prepare fatty acid isopropyl, wherein the organic catalyst is toluenesulfonic acid or sulfarnic acid which usage is 0.2-0.8% of the total weight of fatty acid and isopropyl alcohol, and the mol ratio between fatty acid and isopropyl alcohol is 1:4.0-10.0. The invention reasonably utilizes the reflux esterification reaction in the presence of organic acid catalyst, without toxic water carrying agent, but with simple process and less pollution, while the given isopropyl alcohol can be circulated to effectively reduce cost, with high product quality, high purity and wide application in cosmetic or the like.

The invention relates to an oligomeric quaternary ammonium salt bactericide and a preparation method thereof. Ester p-toluenesulfonate-based gemini quaternary ammonium salt, guanidine hydrochloride and sodium alkoxide are added into solvent, stirred and heated to 120 DEG C to 180 DEG C, heating is stopped after 10 to 48 hours of reaction, so that a crude product is obtained, and after post-treatment, the oligomeric quaternary ammonium salt bactericide is obtained; and the substance amount ratio of the ester p-toluenesulfonate-based gemini quaternary ammonium salt, the guanidine hydrochloride and the sodium alkoxide is (0.008 to 0.040):0.008:0.008. The gemini quaternary ammonium salt is introduced to a plurality of active sites, eight active sites are contained in the structure of the oligomeric quaternary ammonium salt bactericide, the oligomeric quaternary ammonium salt bactericide can show good water solubility and surface activity in aqueous solution, and an important role is played in the process of oligomeric quaternary ammonium salt preparation. A bacteria killing test on three types of bacteria, i.e. sulfate reducing bacteria, iron bacteria and saprophytic bacteria, indicates that the oligomeric quaternary ammonium salt bactericide has a good bactericidal effect.

The invention discloses a water-based passivation agent formula and a process for antirust treatment of steel components. A steel component can be subjected to antirust treatment by soaking the steel component in the water-based passivation agent at room temperature in an environment with pH value of 9.5 to 13 for 3 to 6 min, wherein the water-based passivation agent contains (per unit) sodium nitrite 1 to 10 g / L, triethanolamine 0.5 to 10 ml / L, sodium molybdate 0.1 to 5 g / L, sodium lauryl benzenesulfate 0 to 5 g / L, sodium carbonate 0 to 5 g / L, sodium phosphate 0 to 5 g / L, and sodium p-toluenesulfonate 0 to 5 g / L. The water-based passivation agent formula has the advantages of low cost and long use cycle, and is environment friendly and superior to the prior purchased organic passivation solution in antirust effect.

The invention discloses quaternary phosphonium salts with p-toluenesulfonate as anions as well as a synthesis method, a preparation method and an application of the quaternary phosphonium salts. The synthesis method adopts a simple two-step synthesis route, that is, diethylene glycol monomethyl ether / methoxypolyethylene glycols reacts with p-methyl benzene sulfonic chloride to prepare diethylene glycol monomethyl ether / methoxypolyethylene glycol p-toluenesulfonate, then, diethylene glycol monomethyl ether / methoxypolyethylene glycol p-toluenesulfonate further reacts with triphenylphosphonium toobtain diethylene glycol monomethyl ether / methoxypolyethylene glycol-triphenyl phosphine p-toluenesulfonate. Through the simple synthesis route, the product has good dissolution property and cell penetrability, better antibacterial and killing performance for microbes and an anti-tumor function.

A novel process for the synthesis of Lacosamide using D,L-serine as starting material is described, where the methylation reaction of hydroxyl is carried out using an inexpensive base such as NaOH and an inexpensive alkylating agent, non-toxic and non-carcinogenic, such as methyl p-toluenesulfonate; the R enantiomer is isolated from the racemic mixture of Lacosamide after selective hydrolysis of the acetamide, salification of the racemic mixture with a chiral acid (HX*) in an organic solvent, resolution of the diastereoisomeric mixture, preferably by precipitation of the R enantiomer, and subsequent acetylation of the optically pure intermediate.

The invention discloses a high-yield high-purity DAST source powder synthetic process. The synthetic process comprises the following two steps: 1, reacting 4-methylpyridine with methyl p-toluenesulfonate in the presence of absolute ethyl alcohol serving as a solvent to obtain an absolute ethyl alcohol solution of 4-methyl-N-methylpyridine tosilate; and 2, reacting 4-methyl-N-methylpyridine tosilate with p-dimethylaminobenzaldehyde in the presence of absolute ethyl alcohol serving as a solvent and under the catalytic action of di-n-butylamine or piperidine, so as to obtain high-yield (85-95%) high-quality (90-95%) DAST source powder. According to the synthetic process, absolute ethyl alcohol is used as a reaction solvent, harm of poisonous and harmful solvents such as methylbenzene and methyl alcohol to the body of an operator can be avoided and the pollution of waste liquid to the environment can be avoided. The research success of the high-yield high-purity DAST source powder synthetic process is beneficial to culture of high-quality large-sized DAST crystal, thereby laying a good material and theoretical basis for research on the DAST crystal and related products.

The invention discloses a preparation method of tranexamic acid. According to the preparation method, the tranexamic acid is obtained through catalytic hydrogenation and conversion of p-aminomethylbenzoic acid, wherein the catalytic hydrogenation and the conversion are performed under an alkaline condition; the alkaline condition is constructed by adding sodium hydroxide or potassium hydroxide, ofwhich the molar amount is twice of that of the p-aminomethylbenzoic acid, only in the catalytic hydrogenation stage; the catalytic hydrogenation pressure is 2.5-3.0MPa; the catalytic hydrogenation temperature is 100-120 DEG C; a catalyst used during the catalytic hydrogenation is Raney nickel, a ruthenium carbon catalyst or a palladium carbon catalyst; the conversion pressure is 1.5-2.0MPa; the conversion temperature is 190-210 DEG C; after the conversion, p-toluenesulfonate formation and resin exchange refining are further included. The catalytic hydrogenation and the conversion under the alkaline condition are selected, so that the production cost can be reduced and benefits to a human body and the environment are higher; therefore, the preparation method is suitable for industrial massproduction.