608-25-3Relevant articles and documents
Method for synthesizing 2,6-dihydroxytoluene by using waste acid
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Paragraph 0022-0025, (2021/08/07)
The invention discloses a method for synthesizing 2,6-dihydroxytoluene by using waste acid mechanically. According to the method, 3-chloro-2-methylaniline is taken as a raw material, an intermediate 3-chloro-2-methylphenol is synthesized through diazotization and hydrolysis, the reaction is optimized in the alkali fusion, acidification and refining processes, the mechanical application of waste acid and a solvent in the reaction and the optimization of a refining scheme are emphatically optimized, the yield is effectively improved, three wastes are reduced, and 2,6-dihydroxytoluene is synthesized. The method provided by the invention greatly reduces the generation of acidic wastewater, better meets the requirement of environmental protection, and effectively increases the yield of the product, and the quality of the product reaches 99.0-99.5%.
Method for continuously producing 2, 6-dihydroxytoluene
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Paragraph 0014; 0020-0023, (2021/08/11)
The invention discloses a method for continuously producing 2, 6-dihydroxytoluene. According to the method, 3-chloro-2-methylaniline is taken as a raw material, diazotization is carried out through a micro-channel reactor to synthesize an intermediate 3-chloro-2-methylphenol, and then 2, 6-dihydroxytoluene is synthesized. According to the method, the micro-channel reactor is used for diazotization of 3-chloro-2-methylaniline so that severe heat release and unstable properties of the product in the reaction process can be effectively avoided, the retention time is short, the next reaction is directly carried out after the reaction is finished, the continuous reaction can be experimented, the yield of the diazotization step can be increased to 85-95% from the traditional 75-85%, the total yield of the 2, 6-dihydroxytoluene is increased to 80-90%, and the product purity can be up to more than or equal to 99.0%.
Method for synthesizing M-hydroxyanisole
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Paragraph 0032-0033; 0052-0053; 0056-0057; 0060-0063, (2021/11/03)
The invention provides a method for synthesizing M-hydroxyanisole. Belong to organic synthesis technical field. The synthesis method comprises the following steps: a vapor phase mixture of resorcinol and methanol is subjected to alkylation reaction through a metal phosphate - alumina fixed phase catalyst to obtain m-hydroxyanisole. The method adopts the gas-solid phase alkylation method to synthesize the M-hydroxyanisole without separating the reaction product from the catalyst, has the characteristic of continuous reaction, and can realize continuous production in the industrial production process. The method utilizes the acid-base catalytic activity center on the surface of the stationary phase catalyst to catalyze the reaction of resorcinol and methanol, and has high resorcinol conversion rate. The method has the advantage of high selectivity of m-hydroxyanisole. Methanol is used as a methylation reagent, and the method is environmentally friendly, low in cost and high in economic benefit.
Synthesis method of 2,6-dihydroxytoluene
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Paragraph 0041-0046; 0050-0052, (2021/11/27)
The invention belongs to the technical field of organic chemical synthesis, and particularly relates to a synthesis method of 2,6-dihydroxytoluene. The synthesis process comprises the following steps: S1, mixing 2,6-dihalogenated toluene, alkali, a heavy metal salt catalyst and an adsorbent, and heating and hydrolyzing to obtain a salt solution of 2,6-dihydroxytoluene; S2, adjusting the pH value of the 2,6-dihydroxytoluene salt solution obtained in the previous step to be weakly acidic by using an acid, separating a separated solid, and purifying to obtain a pure product of 2,6-dihydroxytoluene. The adopted main raw materials, such as 2,6-dichlorotoluene, cuprous chloride, sodium dodecyl sulfate and potassium hydroxide, are common chemical raw materials in the market, and are cheap, easy to obtain and wide in source; the synthesis route is short, steps are few, operation is simple, and production cost is greatly saved; reaction conditions are mild, and industrial production is facilitated; the process route is less in three wastes, the catalyst and the adsorbent can be repeatedly used, emission of the three wastes is further reduced, and the method is environment-friendly; the yield of the whole route is high, and the cost advantage is remarkable.
Method for simultaneously preparing 2-methyl resorcinol and 4-methyl resorcinol
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Paragraph 0034-0066, (2022/01/10)
The invention provides a method for simultaneously preparing 2-methyl resorcinol and 4-methyl resorcinol, and belongs to the technical field of organic synthesis. The method comprises the following steps: resorcinol and methanol are subjected to an alkylation reaction through a metal phosphate stationary phase catalyst, and 2-methyl resorcinol and 4-methyl resorcinol are obtained. According to the method, the metal phosphate is used as the catalyst, the 2-methyl resorcinol and the 4-methyl resorcinol can be obtained at the same time by controlling the type of the catalyst, the resorcinol conversion rate is high, the joint selectivity of the 2-methyl resorcinol and the 4-methyl resorcinol can reach 60% at most, the selectivity of other products, namely intermediate hydroxyanisole is about 30%, the selectivity of m-xylylene dimethyl ether is about 5%, and the obtained products are all important intermediates for fine chemical engineering, organic chemistry and drug synthesis and are high in economic benefit. Meanwhile, methanol is used as a methylation reagent, so that the method is environment-friendly and low in price, and the production cost is reduced.
Synthesis method of 2, 6-dihydroxytoluene
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Paragraph 0010-0012, (2020/09/16)
A synthetic method of 2, 6-dihydroxytoluene comprises the following steps: adding 3-chloro-2-methylphenol, a sodium formate solution, cuprous chloride, sodium hydrosulfite and a caustic soda flake solution into a high-pressure kettle, performing nitrogen replacement, heating to 195-200 DEG C, keeping the temperature for 1.5 hours, cooling to 110 DEG C, pressing into an acidification kettle, washing the kettle with water to obtain an alkali melt, and merging into the acidification kettle; adding water into the alkali melt in the acidification kettle, dropwise adding hydrochloric acid until thepH value is 2-3, cooling to 30 DEG C, filtering, adding sodium chloride and ethyl acetate into the filtrate, and stirring; standing for layering, removing a water layer, stirring an organic layer andwashing with a 75% sodium carbonate solution, standing for layering, and removing a water layer,; removing ethyl acetate from an organic phase, adding toluene for dehydration, cooling, centrifuging, adding water, and refining to obtain a finished product. The method is reasonable in synthesis process and low in cost, the water layer (namely wastewater) generated in the production process is recycled after distillation, the production cost is saved, waste gas is recycled through condensation, pollution to the environment is greatly reduced, and the environment is protected.
Preparation method of 2,6-dihydroxytoluene
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, (2018/04/27)
The invention discloses a preparation method of 2,6-dihydroxytoluene. The preparation method comprises the following steps of dissolving prepared 3,5-diamino-4-methylbenzoic acid in water, adding dilute sulphuric acid, stirring uniformly, adding ZnCl2, reducing the temperature to minus -2 to 2 DEG C after stirring uniformly, dropwise adding a sodium nitrite solution into the mixture, continuouslystirring to react for 5-6 hours after the dropwise adding is finished, then adding water and dilute sulphuric acid, mixing uniformly, then heating for boiling, reacting for 30-45 minutes, then addingsodium hydroxide, carrying out reflux reaction for 1-2 hours, cooling to room temperature, adding diethyl ether, stirring for 20-40 minutes, then adding zeolite, stirring and mixing for 1-2 hours, carrying out reduced-pressure distillation after filtering, and preparing the 2,6-dihydroxytoluene. The preparation method disclosed by the invention has the beneficial effects that the raw-material costis low, the operation is simple, safe and reliable, the requirements for the environmental conditions are mild, the product purity is high and the yield is high.
Method for preparation of 2, 6-dihydroxytoluene
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Paragraph 0051-0063, (2017/08/28)
The invention relates to a method for preparation of 2, 6-dihydroxytoluene. The method comprises (1) methylation reaction: carrying out a methylation reaction process on resorcinol as a raw material, a certain amount of methanol as a solvent and a methylation reagent in the presence of a solid acid as a catalyst in a fixed bed reaction device, (2) distillation: carrying out reduced pressure distillation on the reaction liquid, recovering the solvent and collecting a crude product of 2, 6-dihydroxytoluene, and (3) purification: carrying out recrystallization on the crude product of 2, 6-dihydroxytoluene to obtain a refined product of 2, 6-dihydroxytoluene. The method improves the quality of the product, reduces environmental pollution, reduces a cost, is simple in operation, realizes clean and eco-friendly product production and is suitable for mass production.
A 2,6-di-hydroxy toluene synthesis method
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Paragraph 0046-, (2017/03/08)
The invention discloses a synthesis method for 2, 6-dihydroxytoluene. According to the method, the 2, 6-dihydroxytoluene is obtained from 3-chloro-2-methylaniline is used as raw materials through diazotization reaction, lanthanum phosphate catalysis hydrolysis, alkali dissolution and acidification. The synthesis method has the advantages that (1) the raw material resources are wide; (2) the process is simple, and the operation is easy; (3) active rear earth is used as catalysts, and the color and luster of products can be optimized; (4) the reaction conditions are relatively mild, and the safety factor is high; (5) the total yield is as high as more than 65 percent, the purity reaches more than 99.0 percent, in addition, solvents can be recovered and reused, and the energy-saving and emission-reduction effects are obvious.
Reaction-activated palladium catalyst for dehydrogenation of substituted cyclohexanones to phenols and H2 without oxidants and hydrogen acceptors
Zhang, Jingwu,Jiang, Qiangqiang,Yang, Dejun,Zhao, Xiaomei,Dong, Yanli,Liu, Renhua
, p. 4674 - 4680 (2015/07/27)
It is widely believed that the dehydrogenation of organic compounds is a thermodynamically unfavorable process, and thus requires stoichiometric oxidants such as dioxygen and metal oxides or sacrificial hydrogen acceptors to remove the hydrogen from the reaction mixture to drive the equilibrium towards the products. Here we report a previously unappreciated combination of common commercial Pd/C and H2 which dehydrogenates a wide range of substituted cyclohexanones and 2-cyclohexenones to their corresponding phenols with high isolated yields, with H2 as the only byproduct. The reaction requires no oxidants or hydrogen acceptors because instead of removing the generated hydrogen with oxidants or hydrogen acceptors, we demonstrated it can be used as a cocatalyst to help power the reaction. This method for phenol synthesis manifests a high atom economy, and is inherently devoid of the complications normally associated with oxidative dehydrogenations.
