1061results about "Carboxylic acid nitrile purification/separation" patented technology

The invention discloses a technique for treating the tail gas of an acrylonitrile device, which is suitable for treating acrylonitrile tail gas discharged by the acrylonitrile device. The technique is characterized in that: after free water is separated out by a gas-liquid separator, the acrylonitrile tail gas is mixed with air, a noble metal monolithic catalyst is taken as a catalyst and catalytic oxidation reaction is carried out to turn harmful volatile organic compounds into carbon dioxide and water; then a selective reduction monolithic catalyst is taken as a catalyst and selective catalytic reduction reaction with added ammonia is carried out to reduce nitrogen oxide in the tail gas into nitrogen and water. The technique has the advantages of simple technique, turning the harmful volatile organic compounds and nitrogen oxide in the tail gas into carbon dioxide, nitrogen and water, without secondary pollution, the test results totally meeting the environmental protection control requirements of the State Standard of China, adopting a tail gas heat exchanger to recycle reaction heat to heat input tail gas, needing no additional fuel during the normal operation process, small system resistance and low operation cost.

A process is described for preparing 3-pentenenitrile, characterized by the following process steps:

• (a) reacting 1,3-butadiene with hydrogen cyanide over at least one catalyst to obtain a stream 1 which comprises 3-pentenenitrile, 2-methyl-3-butenenitrile, the at least one catalyst and 1,3-butadiene,
• (b) distilling stream 1 in a column to obtain a high-1,3-butadiene stream 2 as the top product and a low-1,3-butadiene stream 3 as the bottom product which comprises 3-pentenenitrile, the at least one catalyst and 2-methyl-3-butenenitrile,
• (c) distilling stream 3 in a column to obtain a stream 4 as the top product which comprises 1,3-butadiene, a stream 5 which comprises 3-pentenenitrile and 2-methyl-3-butenenitrile at a side draw of the column, and a stream 6 as the bottom product which comprises the at least one catalyst,
• (d) distilling stream 5 to obtain a stream 7 as the top product which comprises 2-methyl-3-butenenitrile, and a stream 8 as the bottom product which comprises 3-pentenenitrile.

The invention discloses a method for synthesizing acetonitrile through a one-step ammoniating method with acetic acid. The method comprises the following steps of: (1) reacting acetic acid with liquid ammonia in a fixed-bed reactor provided with a catalyst of aluminum oxide to generate a mixed gas containing the acetonitrile; and (2) continuously refining the gas mixture to obtain an acetonitrileproduct. By adopting the method, the acetonitrile product is relatively pure, the purity can reach more than 99.9%, the separation process is relatively simple, the process is short, the energy consumption in the production process is low, the energy consumption of a unit product is about 40% of the energy consumption with a by-product method, and the cost is lower. The separation process adopts a physical separation method, and avoids the problem of generating a great deal of wastewater and waste gas in the chemical process in the by-product method. Meanwhile, because the synthesis method isadopted, the limitation that the yield is restricted by the main product can be thoroughly avoided.

The invention discloses an isophorone fluorescence probe, and a preparation method and an application thereof. The structure of the fluorescence probe is represented by formula I. The preparation method comprises the following steps: adding isophorone, malononitrile and pyridine to a reaction bottle, carrying out heating refluxing under the protection of an inert gas for 18-24h, purifying, adding the above obtained pure product, p-hydroxybenzaldehyde and pyridine to the reaction bottle, carrying out heating refluxing under the protection of the inert gas for 4-18h, purifying, adding the obtained pure product, 2,4-dinitrofluorobenzene and triethylamine to the reaction bottle, stirring above materials for 8-36h, and purifying the obtained mixture to obtain the fluorescence probe. The fluorescence probe has large Stokes shift (182nm), long fluorescence emission wavelength (592nm), high sensitivity and good selectivity, can specifically detect hydrogen sulfide in organisms, environment and foods, has good biomembrane permeability and low cytotoxicity, and also has the advantages of simple synthesis route, high yield and very large practical values.

The invention provides a synthetic system of 3-cyanomethylbenzoic acid methyl ester and a method thereof. The system comprises an acylation reaction vessel used for preparation of m-Toluoyl chloride;a liquid chlorine feeding unit used for storing and conveying liquid chlorine; a chlorination reaction unit which is connected with the acylation reaction vessel and used as a chlorination reaction chamber of m-Toluoyl chloride; a micro-interface generator which is respectively connected with the liquid chlorine feeding unit and the chlorination reaction unit and used for receiving liquid chlorineconveyed by the liquid chlorine feeding unit, crushing the liquid chlorine into micro-droplets with the diameter being micron level and conveying the micro-droplets to the chlorination reaction unitafter the crushing; and an esterification and cyanation reaction unit which is connected with the chlorination reaction unit. In the prior art, m-Toluoyl chloride and liquid chlorine cannot be fully mixed when m-Toluoyl chloride and liquid chlorine react such that yield of 3-cyanomethylbenzoic acid methyl ester is reduced. The above problem is solved by the synthetic system and the method of the invention.

A method for making N,N′-bis(3-aminopropyl)-1,2-ethylenediamine which comprises reacting acrylonitrile and ethylenediamine in about a 2:1 molar ratio to make a N,N′-bis(cyanoethyl)-1,2-ethylenediamine reaction product and hydrogenating the reaction product, the improvement for improving the selectivity of the reactions to N,N′-bis(2-cyanoethyl)-ethylenediamine and to N,N′-bis(3-aminopropyl)-1,2-ethylenediamine which comprises reacting acrylonitrile and ethylenediamine in the presence of 2-30 wt % water, based on total reactants.

A process for treating the acrylonitrile contained waste gas exhausted by the acrylonitrile apparatus includes such steps as mixing said waste gas with air, heating, catalytic oxidizing reaction to decompose the harmful volatile organic substance to CO2 and H2O, recovering heat and exhausting.

The invention relates to a method for purifying high-purity organic solvent acetonitrile for research, including the steps as below: acetonitrile which is used as a raw material reacts with solid alkali at low temperature so as to eliminate unsaturated nitrile; impurities absorbed by high waveband ultraviolet are removed by the adsorption of zeolite and polymeric adsorbent; and a 3A molecular sieve is used for drying and dehydration, and the operations of rectification, filtration and encapsulation are carried out to obtain the product of chromatographic grade, pesticide residue grade and gradient elution grade chromatographic acetonitrile. By the method, the product of chromatographic pure acetonitrile with purity of more than 99.9 percent can be obtained, and can meet the requirement of the pesticide residue grade and gradient elution grade chromatographic acetonitrile, thereby meeting the demand of customers on application of high efficiency liquid chromatography (HPLC) in pesticide residues, filling in the gap of domestic preparation of pesticide residue grade and gradient elution grade chromatographic reagents, reducing the dependency on abroad reagents, and providing the qualified reagents for the inspection of the pesticide residues and the separation and the nature determination of complex medicines.

The invention relates to a method for separating an acetonitrile-methanol-benzene ternary azeotropic system through three-tower pressure-swing distillation. An acetonitrile-methanol-benzene raw material mixed liquor 1 is delivered to an acetonitrile tower T1 via a pressure pump P1 so as to obtain an acetonitrile product 2 at the bottom of the tower, steam at the top of the tower is condensed by a condenser, a part of the steam flows back to the acetonitrile tower T1, and a part of a material flow 5 is conveyed a methanol tower T2 after pressure reduction by a pressure-reducing valve V1; a methanol product 3 is obtained at the bottom of the methanol tower T2, steam at the top of the tower T2 is condensed by a condenser, a part of the steam flows back to the methanol tower T2, and a part of a material flow 7 is conveyed to a benzene tower T3 after pressurization by a pump P2; a benzene product 4 is obtained at the bottom of the benzene tower T3, steam at the top of the tower T3 is condensed by a condenser, a part of the steam flows back to the benzene tower T3, and a part of material flow 9 cyclically returns to the acetonitrile tower T1 via a pressure-reducing valve 2; and the purities and the recovery rates of the acetonitrile product, the methanol product and the benzene product are all greater than 99.90 wt% and 99.50 wt%, respectively. The method provided by the invention can substantially reduce energy consumption in separation process, improves product purity and yield, is simple and uses reasonable apparatuses.

The invention provides a separation method of an ammoniation dehydration product of caprolactam and a synthesis method of hexamethylenediamine. The separation method comprises the following steps: S1,carrying out ammoniation and dehydration reaction on caprolactam and ammonia gas to obtain a product system; S2, carrying out primary condensation treatment on the product system to obtain a caprolactam-containing fraction and a primary gas-phase component; and S3, carrying out secondary condensation treatment on the primary gas-phase component to obtain a 6-aminocapronitrile fraction and a secondary gas-phase component, wherein the temperature of the secondary condensation treatment is lower than that of the primary condensation treatment. According to the separation method, the product system obtained through the reaction is directly subjected to condensation treatment, secondary heating is not needed, continuous operation of the reaction and product separation can be achieved, waste heat can be fully utilized, the separation efficiency is high, the production intensity is high, the separation energy consumption is low, and therefore the whole process is more energy-saving.

The invention relates to a novel energy-saving three-tower continuous extractive distillation technology and an extractive distillation system thereof. The novel energy-saving three-tower continuous extractive distillation technology comprises the steps as follows: a preheated azeotrope system enters a tower body, a preheated extracting agent enters an extractive distillation tower body, raw materials enter the tower body from the tower bottom, infinite reflux operation is performed, a high-purity and light-component product is produced from the tower top, a tower bottom produced liquid enters an extracting agent recovery tower from a sixth tower plate of the extracting agent recovery tower, infinite reflux operation is performed, a high-purity extracting agent is produced from the tower bottom and mixed with a fresh extracting agent and enters the extractive distillation tower, a tower top produced liquid enters an azeotropic distillation tower, infinite reflux operation is performed for one hour, a heavy-component product is produced from the tower bottom, the tower top produced liquid circularly returns to an azeotrope feeding pipe of the extractive distillation tower, is mixed with the raw materials and enters the extractive distillation tower, and production is performed continuously. The novel energy-saving three-tower continuous extractive distillation technology and the extractive distillation system thereof have the advantages of simple technological process, easiness in operation, little investment, high efficiency, short construction period, consumption reduction, remarkable energy saving and obvious increase of azeotrope light-component productivity.

The invention discloses an activated carbon immobilized ionic liquid catalyst and application thereof. The activated carbon immobilized ionic liquid catalyst is prepared from the following steps: performing oxidation treatment and chlorination on activated carbon sequentially, so as to obtain oxidized and chlorinated activated carbon; performing refluxing on the oxidized and chlorinated activated carbon, bromized 1-(2-amino ethyl hydrobromic acid)-3 methylimidazole onium salt ionic liquid and organic amine in tetrahydrofuran for 20-30 h, filtering, and washing and drying filter cakes B, so as to obtain solid products; adding the solid products into a potassium hydroxide solution, stirring for 20-30 h at the temperature of 0-5 DEG C, filtering, washing filter cakes C and drying, so as to obtain the activated carbon immobilized ionic liquid catalyst. The activated carbon immobilized ionic liquid catalyst provided by the invention can be used for catalyzing of knoevenagel condensation, during after-treatment, the activated carbon immobilized ionic liquid catalyst can be separated from reaction mixed liquor through simple centrifuging or filtering only, and the activated carbon immobilized ionic liquid catalyst can be used repeatedly.

Disclosed herein is a method for inhibiting the premature polymerization of ethylenically unsaturated monomers comprising adding to said monomers an effective amount of at least one nitroso inhibitor of the structure:

wherein R₁, R₂, R₃, and R₄ are independently selected from the group consisting of hydrogen, nitro, nitroso, halogen, COOR wherein R is hydrogen or alkyl, alkyl, and heteroatom-substituted alkyl; or adjacent groups R₁, R₂, R₃, and R₄ can be taken together to form a substituted or unsubstituted fused six-membered ring.

Also disclosed is a composition of matter comprising: A) an ethylenically unsaturated monomer and B) at least one nitroso compound of the above-described structure.

The invention provides a preparation method for a 2-(cyclohexenyl) malonic acid derivative and application thereof. The method takes polylefin and a 2-substituted malonic acid derivative as raw materials, the two materials are subjected to a cyclization reaction in the presence of catalyzer, and the 2-(cyclohexenyl) malonic acid derivative is obtained. Compared with the prior art, the preparationmethod adopts a completely different strategy and has the special functions that (1) a 2-(2, 6-disubstituted cyclohexenyl) malonic acid derivative can be more efficiently synthesized; (2) the reactionyield is high, the reaction conditions are mild, the three wastes are less, and the method is beneficial to industrial production. More importantly, the method expands the application of the 2-(cyclohexenyl) malonic acid derivative in organic synthesis, especially the synthesis of a 2-aryl malonic acid derivative and corresponding pesticides such as a herbicide of pinoxaden.

The invention relates to a new process for producing high-purity iminodiacetonitrile. The new process is characterized in that: high-purity reaction liquid is obtained by using a process for synthesizing iminodiacetonitrile at high conversion rate; and white or pale yellow high-purity iminodiacetonitrile with iminodiacetonitrile content of over 99 percent is produced by using a synthesis reaction liquid decolorizing process, an impurity removal process and three crystallization processes, wherein a part of thin waste liquid produced during the production is returned to a raw material preparation system, the rest part of waste liquid is conveyed to a biochemical device for processing, and the produced thick waste liquid is directly conveyed to an incinerator for processing, so that pollution-free production of the entire process is realized. The new process has the advantages of high product quality, white color, purity of over 99 percent high product yield, iminodiacetonitrile yield of about 90 percent during the entire production process and low three-waste treatment difficulty.

The invention provides a process method for producing high-purity chlorothalonil. The process method has the characteristics of comprising the steps of: sending raw materials containing chlorothalonilm-phthalodinitrile, trichloro-m-phthalodinitrile, pentachloro benzonitrile, hexachloro benzene and water to a light-component removing tower, collecting a mixture of the chlorothalonil containing light components with a mass fraction of <= 0.01% with heavy components from the tower bottom of the light-component removing tower, sending the mixture to a product tower, and collecting the chlorothalonil product with a mass fraction of >= 99.5% from the tower top of the product tower. According to the process method for producing the high-purity chlorothalonil, a rectification process method is adopted to refine the chlorothalonil, the operation process is simple, and the chlorothalonil product with a mass fraction of 99.5% or above can be obtained.

The present invention relates to method of separating methanol-acetonitrile azeotrope. By means of the feature of methanol-acetonitrile azeotrope system with positive deviation to Raoult's law, the pressure of the system is lowered or raised to shift the binary azeotropic point and alter the composition of the azeotrope system, so as to reach the separation aim. The decompressing rectification tower has a theoretical plate number of at least 40 and top pressure of 0.3-0.5atm, and compressing rectification tower has a theoretical plate number of at least 25 and top pressure of 5-10 atm. The method can obtain separated methanol and acetonitrile products of purity over 99.5 wt%, has short technological process, easy control and other advantages, and is suitable for separating methanol-acetonitrile solution in different ratio.