Preparation process of isobutylbenzene

Abstract

The invention relates to the technical field of synthesis of medical intermediates, in particular to a preparation process of isobutylbenzene. The preparation process of the isobutylbenzene comprises the following steps: (1) taking methylbenzene and propylene as raw materials, taking sodium carbonate as a carrier, adding a catalyst and an emulsifier, and carrying out a synthetic reaction until the pressure is not reduced; (2) after the synthetic reaction is finished, adding water to deactivate the catalyst, and then washing with water to obtain a synthetic solution; and (3) carrying out multi-tower rectification on the synthetic liquid to obtain isobutylbenzene. The purpose of adding the emulsifier is to improve the solubility of the catalyst in the reaction liquid, and the yield is improved; consumption of metal potassium and sodium carbonate is reduced, raw material cost is reduced, and wastewater amount is reduced; and the problem that the pipeline is easily blocked is solved, and the operation is safer.

Description

Technical Field

[0001] The invention relates to the technical field of pharmaceutical intermediate synthesis, and in particular to a preparation process of isobutylbenzene. Background Art

[0002] Isobutylbenzene is an important organic compound with a unique chemical structure and wide application value. Isobutylbenzene, molecular formula C 10 H 14 , is a benzene ring derivative with four carbon atom side chains, widely used in chemical, pharmaceutical, pesticide and other fields.

[0003] The preparation process of isobutylbenzene is to use toluene and propylene as raw materials, and carry out side chain alkylation reaction in the presence of an alkaline catalyst. In the reaction process, the hydrogen atoms on the benzene ring of toluene are replaced by the methyl groups of propylene to generate isobutylbenzene. After the synthesis reaction is completed, water is added to deactivate the catalyst, and then the synthesis liquid is obtained after washing with water. The synthetic liquid is separated and purified by distillation to obtain isobutylbenzene. In the prior art, the main disadvantages of using toluene and propylene as raw materials to prepare isobutylbenzene are: large amounts of catalysts and carriers are used in the synthesis reaction process, there are many side reactions, a large amount of wastewater, easy clogging of pipelines, and unsafe operation.

[0004] Therefore, it is urgent to develop an environmentally friendly process that can reduce the amount of catalysts and carriers and have fewer side reactions. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a process for preparing isobutylbenzene, wherein the solubility of the catalyst in the reaction solution is increased and the yield is improved by adding an emulsifier.

[0006] The preparation process of isobutylbenzene of the present invention comprises the following steps:

[0007] (1) Using toluene and propylene as raw materials, sodium carbonate as a carrier, adding a catalyst and an emulsifier, and carrying out a synthesis reaction until the pressure does not drop;

[0008] (2) After the synthesis reaction is completed, water is added to deactivate the catalyst, and then the catalyst is washed with water to obtain a synthesis liquid;

[0009] (3) The synthetic liquid is subjected to multi-tower distillation to obtain isobutylbenzene.

[0010] Furthermore, the feeding molar ratio of toluene to propylene is 1:(0.7-1.0).

[0011] Furthermore, the amount of the catalyst used is 0.8-1.5% of the mass of toluene.

[0012] Furthermore, the amount of sodium carbonate used is 2-6% of the mass of toluene.

[0013] Furthermore, the emulsifier is one or more of saturated fatty acids, unsaturated fatty acids, and oils.

[0014] Furthermore, the emulsifier is one or more of stearic acid, linoleic acid, and soybean oil.

[0015] Furthermore, the mass ratio of the emulsifier to toluene is 1:(500-2000).

[0016] Furthermore, the synthesis reaction temperature is no more than 250°C.

[0017] Furthermore, the amount of water added is 3-8% of the mass of toluene.

[0018] Furthermore, the catalyst is metallic potassium.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) In the process for preparing isobutylbenzene of the present invention, the purpose of adding the emulsifier is to increase the solubility of the catalyst in the reaction solution, which is beneficial to improving the yield. After using the emulsifier, the yield is increased by about 4%.

[0021] (2) The preparation process of isobutylbenzene described in the present invention reduces the amount of metallic potassium and sodium carbonate used, reduces the cost of raw materials, and reduces the amount of wastewater.

[0022] (3) The preparation process of isobutylbenzene described in the present invention reduces the amount of sodium carbonate used, solves the problem of easy pipeline blockage, and makes the operation safer. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with embodiments, but the protection scope of the present invention is not limited thereto.

[0024] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0025] Example 1

[0026] The preparation process of isobutylbenzene comprises the following steps:

[0027] (1) 400 g of toluene and 165 g of propylene are used as raw materials, 20 g of sodium carbonate is used as a carrier, 5 g of potassium metal and 0.5 g of stearic acid as an emulsifier are added, the temperature is raised, and the temperature is controlled to be lower than 250° C. for synthesis reaction, and the reaction is continued until the pressure does not drop. After the reaction is completed, the temperature is lowered and the material is discharged;

[0028] (2) After the synthesis reaction is completed, 20 g of water is added to deactivate the catalyst, and then the catalyst is washed with water to obtain a synthetic liquid;

[0029] (3) The synthetic liquid is distilled through a low-boiling tower to remove low-boiling substances, then distilled through a toluene removal tower to remove toluene, and finally distilled through an isobutylbenzene tower to obtain 279 g of isobutylbenzene; the yield is 53.0%.

[0030] Example 2

[0031] The preparation process of isobutylbenzene comprises the following steps:

[0032] (1) 400 g of toluene and 165 g of propylene are used as raw materials, 20 g of sodium carbonate is used as a carrier, 5 g of potassium metal, 0.1 g of linoleic acid and 0.4 g of soybean oil are added as emulsifiers, the temperature is raised, and the temperature is controlled to be lower than 250° C. for synthesis reaction, and the reaction is continued until the pressure does not drop. After the reaction is completed, the temperature is lowered and the material is discharged;

[0033] (2) After the synthesis reaction is completed, 30 g of water is added to deactivate the catalyst, and then the catalyst is washed with water to obtain a synthetic liquid;

[0034] (3) The synthetic liquid is distilled through a low-boiling tower to remove low-boiling substances, then distilled through a toluene removal tower to remove toluene, and finally distilled through an isobutylbenzene tower to obtain 282 g of isobutylbenzene; the yield is 53.6%.

[0035] Example 3

[0036] The preparation process of isobutylbenzene comprises the following steps:

[0037] (1) 400 g of toluene and 165 g of propylene are used as raw materials, 20 g of sodium carbonate is used as a carrier, 5 g of potassium metal, and emulsifiers: 0.1 g of linoleic acid and 0.3 g of stearic acid are added, the temperature is raised, and the temperature is controlled to be lower than 250° C. for synthesis reaction, and the reaction is continued until the pressure does not drop. After the reaction is completed, the temperature is lowered and the material is discharged;

[0038] (2) After the synthesis reaction is completed, 15 g of water is added to deactivate the catalyst, and then the catalyst is washed with water to obtain a synthetic liquid;

[0039] (3) The synthetic liquid is distilled through a low-boiling tower to remove low-boiling substances, then distilled through a toluene removal tower to remove toluene, and finally distilled through an isobutylbenzene tower to obtain 277 g of isobutylbenzene; the yield is 52.6%.

[0040] Comparative Example

[0041] (1) 400 g of toluene and 165 g of propylene are used as raw materials, 50 g of sodium carbonate is used as a carrier, 8 g of potassium metal is added, the temperature is raised, and the temperature is controlled to be lower than 250° C. for synthesis reaction, and the reaction is continued until the pressure does not drop. After the reaction is completed, the temperature is lowered and the material is discharged;

[0042] (2) After the synthesis reaction is completed, 30 g of water is added to deactivate the catalyst, and then the catalyst is washed with water to obtain a synthetic liquid;

[0043] (3) The synthetic liquid is distilled through a low-boiling tower to remove low-boiling substances, then distilled through a toluene removal tower to remove toluene, and finally distilled through an isobutylbenzene tower to obtain 247 g of isobutylbenzene; the yield is 47.0%.

Claims

1. A process for preparing isobutylbenzene, It is characterized in that The following steps are involved: (1) Using toluene and propylene as raw materials, sodium carbonate as a carrier, adding a catalyst and an emulsifier, and carrying out a synthesis reaction until the pressure does not drop; (2) After the synthesis reaction is completed, water is added to deactivate the catalyst, and then the catalyst is washed with water to obtain a synthesis liquid; (3) The synthetic liquid is subjected to multi-tower distillation to obtain isobutylbenzene.

2. The process for preparing isobutylbenzene according to claim 1, It is characterized in that The feeding molar ratio of toluene to propylene is 1:(0.7-1.0).

3. The process for preparing isobutylbenzene according to claim 1, It is characterized in that The amount of the catalyst used is 0.8-1.5% of the mass of toluene.

4. The process for preparing isobutylbenzene according to claim 1, It is characterized in that The amount of sodium carbonate used is 2-6% of the mass of toluene.

5. The process for preparing isobutylbenzene according to claim 1, It is characterized in that The emulsifier is one or more of saturated fatty acids, unsaturated fatty acids, and oils.

6. The process for preparing isobutylbenzene according to claim 5, It is characterized in that The emulsifier is one or more of stearic acid, linoleic acid and soybean oil.

7. The process for preparing isobutylbenzene according to claim 1, It is characterized in that The mass ratio of the emulsifier to toluene is 1:(500-2000).

8. The process for preparing isobutylbenzene according to claim 1, It is characterized in that The synthesis reaction temperature is no more than 250°C.

9. The process for preparing isobutylbenzene according to claim 1, It is characterized in that The amount of water added is 3-8% of the mass of toluene.

10. The process for preparing isobutylbenzene according to claim 1, It is characterized in that The catalyst is metallic potassium.