阅读说明：本技术 一种酸性离子液体[PPh3][TfOH]3催化制备环己基苯的方法 (Acidic ionic liquid [ PPh3][TfOH]3Method for catalytically preparing cyclohexylbenzene ) 是由 王爱玲 张腾 崔颖娜 王帆 郑学仿 于 2019-08-29 设计创作，主要内容包括：本发明涉及一种酸性离子液体[PPh_3][TfOH]_3催化制备环己基苯的方法。该方法具体为：将三苯基膦：三氟甲磺酸按摩尔比为1:3的比例合成[PPh_3][TfOH]_3催化剂。以[PPh_3][TfOH]_3为催化剂,于40-80℃条件下缓慢滴加苯与卤代环己烷的混合液,反应1-3h制备环己基苯。本发明在制备环己基苯过程中,反应体系不需要加入其它有机溶剂,[PPh_3][TfOH]_3作反应催化剂兼溶剂。且本发明的[PPh_3][TfOH]_3可重复使用,绿色环保。本发明提供的制备方法工艺简单,反应后处理简单方便,绿色环保。(The invention relates to an acidic ionic liquid [ PPh 3 ][TfOH] 3 A method for preparing cyclohexylbenzene by catalysis. The method specifically comprises the following steps: mixing triphenylphosphine: triflic acid is synthesized into [ PPh ] according to the molar ratio of 1:3 3 ][TfOH] 3 A catalyst. With [ PPh ] 3 ][TfOH] 3 As a catalyst, slowly dripping the mixed solution of benzene and halogenated cyclohexane at the temperature of 40-80 ℃ to react for 1-3h to prepare the cyclohexylbenzene. In the process of preparing the cyclohexylbenzene, other organic solvents are not required to be added into a reaction system, [ PPh ] 3 ][TfOH] 3 Used as a reaction catalyst and a solvent. And [ PPh ] of the present invention 3 ][TfOH] 3 Can be repeatedly used, and is green and environment-friendly. The preparation method provided by the invention is simple in process, simple and convenient in post-reaction treatment, and green and environment-friendly.)

1. Acidic ionic liquid [ PPh₃][TfOH]₃The method for preparing the cyclohexylbenzene by catalysis is characterized in that the cyclohexylbenzene is prepared by taking IL as a catalyst and a mixed solution of benzene and halogenated cyclohexane as a substrate and reacting for 1-3h at the temperature of 40-80 ℃, wherein the IL is prepared from PPh₃Prepared in a 1:3 molar ratio to TfOHAn ionic liquid; the molar ratio of the halogenated cyclohexane to the IL is 1:1, the molar ratio of benzene to halogenated cyclohexane is 1: 1-32: 1.

2. The process for preparing cyclohexylbenzene as set forth in claim 1, characterized in that the molar ratio of benzene to halocyclohexane is 4: 1.

3. The method for preparing cyclohexylbenzene according to claim 1, characterized in that the feeding of the mixed solution of benzene and halogenated cyclohexane is carried out in such a manner that: and (4) dropwise adding.

4. The process for producing cyclohexylbenzene according to claim 1, characterized in that the halogenated cyclohexane is fluorocyclohexane, chlorocyclohexane, bromocyclohexane.

5. The method for preparing cyclohexylbenzene according to claim 1, characterized in that IL is added into a reaction vessel, then benzene and halogenated cyclohexane are mixed according to a molar ratio of 4:1, the mixture is added into the reaction vessel in a dropwise manner, the reaction is stopped after stirring and reacting for 1-3h at 80 ℃, the reaction is cooled to room temperature, and a target product is obtained after column separation treatment, wherein the molar ratio of halogenated cyclohexane to IL is 1: 1.

6. the process for producing cyclohexylbenzene according to claim 5, characterized in that the halogenated cyclohexane is chlorocyclohexane.

Technical Field

The invention relates to a method for preparing a cyclohexylbenzene compound by catalysis, in particular to a method for preparing a cyclohexylbenzene compound by utilizingAcidic ionic liquid catalyzed Friedel-Crafts alkylation reactionA process for producing cyclohexylbenzene.

Background

Cyclohexylbenzene is an important chemical intermediate with high boiling point and freezing point close to room temperature^[1]Cyclohexylbenzene plays an important role in many fields as a fine chemical product with high added value and wide market prospect^[2]. The cyclohexylbenzene is one of raw materials for synthesizing TFT liquid crystal material, and has the characteristics of good chemical stability, photochemical stability, low viscosity and the like due to the special physicochemical properties of the cyclohexylbenzene^[3]. It can also be used as additive to be applied to lithium battery electrolyte, so that the overcharge-preventing performance of the battery is greatly improved, the safety of the lithium battery is further improved, and the cyclicity and the electrochemical performance of the battery are not influenced^[4-5]. In the future, when the traditional energy is gradually faded, the clean energy is more and more widely applied, and the trend can drive the vigorous demand of the cyclohexylbenzene. According to data, the dosage of the cyclohexylbenzene in the lithium ion battery electrolyte as an additive is about 2 to 5 percent, and the market demand potential is huge^[6]。

One method for synthesizing cyclohexylbenzene is Friedel-Crafts alkylation of benzene with halogenated cyclohexane^[7]. The catalyst for the traditional Friedel-Crafts alkylation reaction is AlCl₃、FeCl₃isoLewis acids^[8]Or protonic acid homogeneous phase^[9]And a heterogeneous catalyst^[10-11]. However, the catalysts have high toxicity and volatility and are highly corrosive to instruments and equipment; the catalyst is excessive in dosage and expensive in price, and is not suitable for industrial production; therefore, the research of designing a mild, green and environment-friendly catalyst to carry out Friedel-Crafts alkylation reaction and synthesizing the cyclohexylbenzene has important significance.

Disclosure of Invention

In order to make up the defects of the prior art, the invention aims to provide a novel environment-friendly reaction system for Friedel-Crafts alkylation reaction to prepare cyclohexylbenzene. Benzene in the reaction system is used as a reactant and an organic solvent. To be provided withAcidic ionic liquids, i.e. [ PPh ]₃][TfOH]₃The catalyst avoids the use of volatile organic solvent and traditional catalyst harmful to the environment, and has higher stability compared with other ionic liquids. The preparation method is safe, cheap and green. The reaction system has the advantages of wide application range, simple operation, low price, safety, higher yield and environmental friendliness.

In order to achieve the purpose, the invention adopts the following technical scheme:

taking IL as a catalyst, mixing benzene and halogenated cyclohexane according to a molar ratio of 1: 1-32: 1, dropwise adding, and reacting at 40-80 ℃ for 1-3h to prepare p-cyclohexylbenzene; the reaction formula is as follows:

wherein said IL is [ PPh ]₃][TfOH]₃。

Wherein IL is formed by triphenylphosphine (PPh)₃) Prepared with trifluoromethanesulfonic acid (TfOH) in a 1:3 molar ratioAn acidic ionic liquid;

the molar ratio of the halogenated cyclohexane to the IL is 1: 1.

further, the feeding mode of the mixed solution of benzene and halogenated cyclohexane is as follows: and (4) dropwise adding.

Further, the mixed solution of benzene and halogenated cyclohexane is respectively added dropwise in the molar ratio of 1:1, 4:1, 8:1, 16:1 and 32:1, and the preferable ratio of benzene: halogenated cyclohexane ═ 4: 1.

And X is F, Cl and Br, namely the halogenated cyclohexane is fluorinated cyclohexane, chlorocyclohexane and bromocyclohexane.

Further, the preparation method of the IL comprises the following steps: adding TfOH dropwise to PPh₃In the formula (1: 3) by mixing PPh₃Mixing with TfOH, heating and stirring at 80-90 deg.C to obtain light yellow liquid, and vacuum dryingDrying in a drying oven overnight to obtain IL [ PPh ]₃][TfOH]₃。

As a preferred embodiment of the present invention, the preparation method of the cyclohexylbenzene compound of the present invention specifically comprises: IL is expressed as [ PPh₃][TfOH]₃Adding the mixture into a reaction vessel, then mixing benzene and halogenated cyclohexane according to a molar ratio of 4:1, adding the mixed solution into the reaction vessel in a dropwise manner, stirring and reacting for 1-3h at 80 ℃, and stopping the reaction. Cooling to room temperature, and performing column separation to obtain the target product. The molar ratio of the halogenated cyclohexane to the IL is 1: 1. the halogenated cyclohexane is preferably chlorocyclohexane.

Compared with the prior art, the invention has the beneficial effects that: the invention avoids adopting volatile organic solvent and traditional catalyst harmful to environment, provides a novel environment-friendly reaction system for Friedel-Crafts alkylation reaction by taking mild, green and environment-friendly IL as the catalyst to prepare the cyclohexylbenzene compound, takes the IL as the catalyst and simultaneously as the solvent, and has safe, cheap and green preparation method. The reaction system has the advantages of wide application range, simple operation, low price, safety, higher yield, environmental protection, suitability for industrial production and important significance for the research of synthetic cyclohexyl benzene compounds.

Detailed Description

The invention is described in more detail below with reference to specific examples, without limiting the scope of the invention. Unless otherwise specified, the experimental methods adopted by the invention are all conventional methods, and experimental equipment, materials, reagents and the like used in the experimental method can be purchased from chemical companies.

The catalyst IL referred to in the following examples was prepared as follows:

5mmol (1.31g) of triphenylphosphine (PPh)₃) Adding the mixture into a 50ml three-neck flask, introducing nitrogen for protection, slowly dropwise adding 15mmol (2.26g) of trifluoromethanesulfonic acid (TfOH) at 0-5 ℃, dropwise adding the mixture after about 30min, stirring the mixture for 1h at 85 ℃ to obtain a white liquid, and drying the white liquid in a vacuum drying oven overnight to obtain the productAcidic ionic liquid [ PPh₃][TfOH]₃。