75 results about "P-nitrotoluene" patented technology

A high selectivity synthesis method of p-nitrobenzaldehyde comprises the following steps: firstly, adding p-nitrotoluene, peroxycarbonate used as catalyst and dichloroethane used as solvent in a reactor, dropping bromine at 40-50 DEG C under stirring, then reacting at 50-60 DEG C to ensure that the color of bromine fades, adding hydrogen peroxide to react at 60-70 DEG C for no less than 4 hours and prepare 4-nitrobenzyl bormide; and secondly, adding 25-35% sodium carbonate solution to hydrolyze at 80-95 DEG C and generate p-nitrobenzyl alcohol, standing to separate, and finally using oxygen as oxidant to react for no less than 25 hours in the presence of catalyst triphenylphosphine metal salt organic complex under the conditions that the temperature is 50-90 DEG C and the pressure 5.1*10<5>-1.0*10<6>. The overall yield of the method is no less than 70%, the product purity is no less than 99% and the dosage of bromine is 50-60% of the theoretical amount.

The invention discloses a cost-saving preparation method of p-nitrobenzyl alcohol. The key points of the technical scheme are as follows: according to the cost-saving preparation method of the p-nitrobenzyl alcohol, p-nitrotoluene is taken as a starting raw material and reacts with chlorine gas to obtain p-nitrobenzyl chloride, and then the p-nitrobenzyl chloride is hydrolyzed in an alkaline solution to obtain p-nitrobenzyl alcohol. Compared with the prior art, the cost-saving preparation method of the p-nitrobenzyl alcohol has the following beneficial effects: the reaction system is simple and the raw material is cheap and easily available; the preparation cost is low and no hazardous waste is generated, so that the preparation method accords with the green production ideal; the cost-saving preparation method is simple in process, simple and convenient to operate, short in reaction time, high in efficiency and suitable for large-scale production.

The invention relates to the field of production of chemical engineering products, in particular to a method for synthesizing p-nitrobenzoic acid. The method comprises the following steps of using p-nitrotoluene as the raw material, using diluted nitric acid as a reaction medium and a catalyst, using oxygen as an oxidant, and oxidizing in a high-pressure kettle, so as to prepare the p-nitrobenzoicacid; cooling, separating crystal form solid in the reaction liquid, sucking and filtering, so as to obtain a mother liquid and filter cake; spraying the filter cake by water, and drying, so as to obtain a light yellow product, namely p-nitrobenzoic acid. The method for synthesizing the p-nitrobenzoic acid has the advantages that the production purity is high, the preparation is simple, the costis low, the pollution is avoided, and the green effect is realized.

The invention discloses a device and method for preparing high purity m/p-nitrotoluene by coupling rectification and crystallization. In the device disclosed by the invention, a negative pressure rectifying tower (6) is connected with a raw material pipeline (1), a condenser (8) is arranged in the top of the negative pressure rectifying tower (6), the bottom of the condenser (8) is connected with an m-nitrotoluene crystallizer (11) through an m-nitrotoluene enriching pipeline (15), an m-nitrotoluene mother liquor (12) is connected with the negative pressure rectifying tower (6), the negative pressure rectifying tower (6) is connected with a vacuum pump (14) through a negative pressure pipeline (14), the bottom of the negative pressure rectifying tower (6) is connected with a falling film reboiler (7) and a circulating pump (9) through a pipeline, the falling film reboiler (7) is connected with a p-nitrotoluene crystallizer (2) through a p-nitrotoluene enriching pipeline (10), and a p-nitrotoluene mother liquor pipeline (4) is communicated with the negative pressure rectifying tower (6). The device disclosed by the invention has reasonable structure, simple process and low comprehensive energy consumption, is convenient in operation and is an ideal preparation device of high purity m/p-nitrotoluene.

The invention discloses an aramid fiber-ultrahigh molecular weight polyethylene composite sheet material processing method. The method comprises fiber impregnation, single fiber layer hot pressing and multiple composite layer hot pressing. First glue comprises a styrene-vinyl acetate copolymer, epoxy resin, terpene resin, polyethylene glycol, p-nitrotoluene and strontium fluoride. Second glue comprises a propylene-vinyl acetate copolymer, polystyrene, terpene resin, polyethylene glycol, 2,4-dimethylphenol and potassium metasilicate. Through improvement of the glue and use of a multi-ingredient composite formula, bonding strength and density of the glue to aramid fibers and polyethylene fibers are effectively improved, and composite sheet material toughness and shock resistance are improved. Through freezing and unfreezing of the fibers subjected to impregnation, glue inner stress and surface tension are effectively reduced. Through UV treatment on the fibers subjected to impregnation, glue and fiber bonding strength is improved and a composite sheet material service life is prolonged.

The present invention relates to a process for preparing dinitrotoluene. The process of the invention for preparing dinitrotoluene from mononitrotoluene, which comprises carrying out a mononitrotoluene nitration reaction using a nitrating mixture comprising nitric acid, sulphuric acid and water resulting in a two-phase medium and separating the organic and aqueous phases of said two-phase medium, is characterized in that the mononitrotoluene nitration is carried out using a nitrating mixture comprising at most 10% by weight of water resulting in a two-phase medium, in that the organic and aqueous phases of said two-phase medium are separated, and in that the aqueous phase derived from the separating operation is recycled, at the end of the mononitrotoluene nitration reaction and before the separation of the organic and aqueous phases, such that the weight ratio of the aqueous phase to the organic phase is at least equal to 1.2.

The invention discloses a method used for producing methylaniline from nitrotoluene through liquid-phase hydrogenation reduction. The production method of methylaniline comprises steps of feeding reduction and pressure-reducing separation. In the feeding reduction process, methanol, a Raney nickel catalyst, hydrogen and nitrotoluene are added to a reaction vessel; under the existence of both the solvent methanol and the catalyst, a liquid-phase catalyzed hydrogenation reaction is carried out, such that nitrotoluene is produced. According to the invention, the controlling requirements of production indexes such as temperature and pressure are low, and the method is advantaged in easy operation and management, high equipment automatic control level, good product quality, high yield, low energy consumption, recoverable catalyst and methanol, low wastewater generation, low tar, good environmental benefit, low operation cost, and high adaptability. The method can be used in reduction reactions of o-, m- or p-nitrotoluene for producing o-, m- or p-methylaniline.

The invention relates to a p-nitrotoluene hydrogenated ruthenium-lanthanum double metal catalyst and a preparation method thereof. The catalyst comprises an active ingredient ruthenium, an auxiliary agent lanthanum and a carrier. The catalyst is shown by x%Ru-y%La/carrier, in which x% represents percentage by mass of Ru in the catalyst, y% represents percentage by mass of La in the catalyst, and the catalyst comprises the following components in percentages by mass: 0.5-5% of Ru, 0.2-2% of La and the balance of carrier. The precursor of the catalyst is prepared by means of an impregnating-precipitating method and is reduced in a hydrogen-containing atmosphere to obtain the p-nitrotoluene hydrogenated ruthenium-lanthanum double metal catalyst. In a reaction of preparing p-methyl-cyclohexylamine by p-nitrotoluene hydrogenation, p-methyl-cyclohexylamine will be strongly adsorbed on the catalyst so as to generate a lot of tar to inhibit the reaction; and by adding lanthanum, the problem that the catalyst strongly adsorb p-methyl-cyclohexylamine is solved well, and the generating amount of tar is reduced.

An improved process for the preparation of p-nitrobenzyl bromide from p-nitrotoluene is disclosed wherein large excess of the reactant in carbon tetrachloride is treated with 2:1 bromide-bromate reagent and the product is isolated efficiently and with high purity through selective cold crystallization from reaction mass so as to allow the mother liquor to be recycled in a subsequent batch without any further work up. The cycles are continued so long as product of desired quality is obtained in adequate yield. Thereafter, the solvent and p-nitrotoluene are recovered from the mother liquor and the residue is treated with sodium borohydride to convert impurities back into reactant or product which is then recycled in the process thereby circumventing the problem of waste disposal and simultaneously yielding the desired product with >95 % yield with respect to p-nitrotoluene and >88 % bromine atom efficiency.

Disclosed is a p-nitrotoluene-2-sulfonic acid continuous synthesis method. The p-nitrotoluene-2-sulfonic acid continuous synthesis method comprises melting or dissolving p-nitrotoluene in organic solvent or inorganic solvent, and inletting the melt of solution together with sulfur trioxide mixed gas into a film sulfonation reactor for sulfonation reaction, filtering liquid reaction products containing the inorganic solvent to remove the inorganic solvent and then feeding the reaction products into an ageing tank, or directly feeding the solvent-free or organic solvent-containing liquid reaction products into the ageing tank for stirred ageing; and performing hydrolysis by adding in deionized water to obtain hydrolyzed products, which, if containing no organic solvent, are p-nitrotoluene-2-sulfonic acid, else, performing extraction by adding in deionized water for dissolution in aqueous phase to obtain the p-nitrotoluene-2-sulfonic acid. The p-nitrotoluene-2-sulfonic acid continuous synthesis method has the advantages of being low in production cost, free from producing waste acid, high in safety performance and capable of achieving continuous production.

The invention relates to a method for removing nitrotoluene in high-concentration waste acid. The method comprises adding an extractant into the high-concentration waste acid at a certain temperature, extracting, and separating the extractant from the waste acid; and recovering the extractant. Compared with the prior art, the invention has significant advantages that the invention has simple treatment steps, significant treatment effect and mononitrotoluene (MNT) and dinitrotoluene (DNT) removal rate up to above 99%, the treated high-concentration waste acid has high purity and can be directly used for other chemical processes, and the invention is suitable for industrialization; a perfluoro solvent serving as the extractant has good fluidity, chemical inertness and good phase separation performance, and has solubility for nitrotoluene compounds at a temperature higher than a critical temperature, thus it can be reutilized and maintains high removal rate; the invention directly treats the high-concentration waste acid without diluting with water, avoids subsequent wastewater treatment, and lowers the cost; and the inventive method has few apparatus, low manufacture cost, low investment and low running cost.

The invention discloses a method for synthesizing o-chloro-p-aminotoluene from o-chloro-p-nitrotoluene through catalytic hydrogenation. The method comprises the following steps: enabling the o-chloro-p-nitrotoluene to be dissolved in a methyl alcohol solvent according to a mass ratio of 1 to 1, and adding a raney nickel catalyst; after dissolving, feeding hydrogen, wherein a molar weight proportion of the o-chloro-p-nitrotoluene to the hydrogen is 1 to (3.5 to 4), controlling a reaction temperature to be 90-95 DEG C, and controlling a reaction pressure to be 1.6-2.2 MPa; while an input amountof the o-chloro-p-nitrotoluene is 1 ton, reducing reaction time is about 5-6 hours; transferring reducing solution to a solvent distillation column, performing atmospheric distillation to obtain coarse o-chloro-p-aminotoluene; transferring the coarse o-chloro-p-aminotoluene to a rectifying tower, performing negative pressure distillation to obtain refined o-chloro-p-aminotoluene, wherein a purityof the o-chloro-p-aminotoluene measured by using a gas chromatographic method is greater than 98.00%. Multi-sulfur waste water and multi-sulfur waste residues are not generated in a production process, the method is energy-saving and environmentally friendly, an operating process of the technology is simple and controllable, and production cost is reduced.

The invention relates to a process for the production of dinitrotoluene by the two-stage nitration of toluene. In the first stage of this process, toluene was reacted adiabatically with nitrating acid so that at least 90% of the toluene was reacted off and no more than 70% of the toluene formed dinitrotoluene. The resulting organic phase containing mononitrotoluene and the aqueous acid phase containing sulfuric acid were separated, and the aqueous acid phase containing sulfuric acid was concentrated by flash evaporation. The resulting concentrated sulfuric acid was recycled into the reaction in the first stage, and/or into the reaction in the second stage, and/or into the concentration in the second stage.

In the second stage, the organic phase containing mononitrotoluene from the first stage was completely reacted isothermally with nitrating acid. The organic phase and the aqueous acid phase containing sulfuric acid were then separated, and the aqueous acid phase containing sulfuric acid was concentrated by vacuum evaporation. The resulting concentrated sulfuric acid was recycled into the reaction in the first stage and/or the second stage.

The invention discloses a preparation method of 4-amino-2-sulfonic benzoic acid, and belongs to the preparation technology of aromatic sulfonic acid. The process of the method comprises the following steps: dissolving raw materials of p-nitrotoluene o-sodium sulfonate, 4-nitro-2- sodium sulfonate benzaldehyde, 4,4'-dinitro diphenylethane-2,2'-disodium disulfonate or 4,4'-dinitro diphenylethene-2,2'-disodium disulfonate in a sodium hydroxide solution, performing oxidation with pressurized air, performing reduction with iron powder, performing filtration and crystallization to obtain 4-amino-2-sulfonic benzoic acid. The invention has a simple process, high yield and purity, and the product 4-amino-2-sulfonic benzoic acid can be prepared into p-aminosalicylic acid through simple alkali fusion technology with high yield and high product purity.

The invention relates to a process for preparing aromatic aldehydes, in particular a process for preparing p-nitrobenzaldehyde through bionic catalytic oxidation of p-nitrotoluene, wherein metallic phthalocyanine, single nuclear metalloporphyrin or mu-oxy-double nuclear metalloporphyrin having the similar structure as the biological enzymes are selected as the catalyst for the disclosed process, whose dose is 0.1-1.0% weight of p-nitrotoluene, and methyl alcohol is used as solvent, 0.5-3.0 MPa oxygen is let into 0.7-2.8 mol/L strong alkaline methyl alcohol solution, controlling the reaction temperature to be 20-65 deg. C, the reaction time being 6-48 hrs.

The invention relates to a production process of p-nitrobenzaldehyde. The production process is characterized in that p-nitrobenzaldehyde is prepared by the sections of bromination, hydrolysis, oxidation, addition, alkali precipitation, refining and the like based on p-nitrotoluene as a raw material. According to the production process provided by the invention, a solvent used when bromination is carried out is dichlorethane, thereby avoiding the environmental protection problem brought by carbon tetrachloride; an unreacted raw material is used as the solvent when oxidation is carried out; when refining is carried out, 80% ethanol is used as the solvent, thereby reducing the influence of an toxic solvent on a human body; and when bromination is carried out, cheap hydrogen peroxide is added, thereby improving the utilization rate of bromine and avoiding the disadvantages of large amount of hydrogen bromide gases on environment and worker operation. Thus, the production process provided by the invention has higher environmental friendliness and safety, and is suitable for industrial production on large scale; and by test, the yield of p-nitrobenzaldehyde is above 65%, and the chromatographic purity of the finished product can reach above 99.5%.

The invention discloses a novel preparation method of 4, 4'-dinitrobibenzyl. According to the method, p-nitrotoluene is used as a reactant, oxygen is used as an oxidizing agent, ethanol is used as a solvent, transition metal doped FDU-12 mesoporous molecular sieve supported guanidine salt ionic liquid is used as a catalyst, and 4, 4 '-dinitrobibenzyl is prepared through high-selectivity oxidative dehydrogenation coupling reaction. After the reaction is finished, the catalyst phase and the product phase are easily subjected to heterogeneous separation and can be well recycled. The method has the advantages of simple operation, mild reaction conditions, small catalyst dosage, high reaction efficiency and selectivity, and small discharge of three wastes, and is a novel green and clean preparation method.

The invention relates to the technical field of chemical materials, in particular to efficient cooling liquid. The efficient cooling liquid is characterized in that being prepared from the following raw materials in parts by weight: 30 to 45 parts of glycerol, 20 to 28 parts of ethanol, 19 to 36 parts of propylene glycol, 8 to 14 parts of sorbitol, 3 to 10 parts of p-nitrotoluene, 2 to 10 parts of phenolic resin, 1.4 to 4.2 parts of sodium fluosilicate, 1 to 7 parts of boric sludge, 5 to 17 parts of polyester fiber, 0.1 to 0.5 part of maleic anhydride, 4 to 8 parts of aromatic amine and 3 to 15 parts of antioxidant. The efficient cooling liquid has the advantages of reasonable composition proportion, stable structure, high cooling efficiency, low production cost, safety, nontoxicity, insusceptibility to volatilization and recyclability.

The invention relates to a device and method for separating a waste sulfuric acid nitro compound. The device comprises a waste acid tank, wherein the left upper portion of the waste acid tank is communicated with a waste acid/nitro compound feeding pipe, the right upper portion of the waste acid tank is connected with a dispersion pipe on a separator through a nitro compound pipeline, the top of the separator is connected to a liquid ring vacuum pump through an exhaust pipe, and inlet and outlet pipelines of the liquid ring vacuum pump are connected through a return valve. The left side of theseparator is connected with a mononitrotoluene pump through a mononitrotoluene discharging pipe I, a transfer tank and a mononitrotoluene discharging pipe II which are sequentially connected, an output of the mononitrotoluene pump is communicated with a DNT tank, the right side of the separator is provided with a sight glass, and the bottom of the separator is connected with a polymer dischargingpipe. By adopting the device and the method for separating the waste sulfuric acid nitro compound, the separation of mononitrotoluene and a polymer can be achieved, the toxicity in acidic wastewateris reduced, the recovered mononitrotoluene is reused to generate economic benefits, and the environmental protection risk is reduced.