Cyclohexanol

1.Material Overview

Cyclohexanol is a colorless, oily, flammable liquid that crystallizes white below its freezing point. It has a melting point of 24°C (freezing point 25.15°C), a boiling point of 161.10°C, and a relative density of 0.9493 (20/4°C).

Cyclohexanol is an important chemical raw material, mainly used in the production of adipic acid, hexamethylenediamine, cyclohexanone, and caprolactam. It is also used as a stabilizer in soaps, in the manufacture of disinfectant soaps and detergent emulsions, and as a solvent for rubber, resins, nitrocellulose, metal soaps, oils, esters, and ethers. Additionally, it is used as an admixture in coatings, and as a degreasing agent, stripping agent, dry cleaning agent, and polishing agent for leather. Cyclohexanol is also a raw material for fiber finishing agents, pesticides, and plasticizers. The reaction of cyclohexanol with phosgene yields cyclohexyl chloroformate, an intermediate in the initiator dicyclohexyl peroxide.

2.Process Introduction

This process uses benzene as the starting material, and involves partial hydrogenation of benzene to produce cyclohexene, followed by hydration of cyclohexene to produce cyclohexanol. The process includes steps such as benzene hydrogenation, extractive distillation, cyclohexene hydration and cyclohexanol purification, cyclohexane distillation, hydrogenation catalyst regeneration, and hydration catalyst regeneration.

The main reaction steps are:

C6H6 + 2H2 → C6H10

C6H10 + H2O → C6H11OH

The two reactions above represent the hydrogenation of benzene and the hydration of cyclohexene, respectively.

   C6H6+2H2→C6H10

   C6H10+H2O→C6H11OH

3.Technical advantages

The process flow is as follows: refined benzene is partially hydrogenated under controlled temperature and pressure in the presence of a ruthenium catalyst to produce cyclohexene and cyclohexane. The conversion rate of benzene is 40-50%, and the selectivity of cyclohexene is 80%. In the presence of a high-silica zeolite catalyst, cyclohexene and water are converted to cyclohexanol. The conversion rate of cyclohexene is 10%, and the selectivity of cyclohexanol is 99%.

Compared with the traditional benzene process, this process has the following main characteristics:

1) The product is of good quality and has high purity;

2) The reaction conditions for partial hydrogenation of benzene are mild, and both the hydrogenation and hydration reactions are carried out in the liquid phase, making the operation safe and requiring no special safety measures;

3) Few byproducts: cyclohexane is the only byproduct and can be sold as a valuable chemical product.

4) It has environmental advantages. The hydrogenation and hydration reaction processes produce monobasic acids, dibasic acids, esters, etc., just like the alkane process. The amount of waste liquid is small, the environmental protection investment is low (there is no need to build a waste alkali incineration boiler), and there is no equipment corrosion.

5) There is no scaling or clogging problem in the production process, resulting in fewer accidents and lower maintenance costs.

4. 技术价值

4.Technical Benefit

Cyclohexanol technology by Tianli mainly uses the cyclohexene method to produce cyclohexanol. This route produces products of superior quality and is more suitable for subsequent production of purified adipic acid.

1) From the perspective of process technology selection: Tianli cyclohexanol technology has advanced overall process technology, low raw material consumption, and good economic benefits. It is currently the dominant production process of adipic acid at home and abroad, and there are already many mature production units in China.

2) From the perspective of cleaner production; Tianli cyclohexanol technology adopts advanced production technology, resulting in high raw material utilization and low consumption, thus generating less waste. All three types of waste generated during the production process are comprehensively treated to meet national and local emission standards, complying with the requirements of cleaner production.

3) From the perspective of safe production and labor protection: cyclohexanol technology by Tianli has taken a series of preventive measures for occupational safety and health, from site layout to equipment layout, from DCS control to SIS safety instrumented system, and from raw material transportation to product delivery. The safety of the equipment and the operating environment are reliable.

4) From the perspective of energy conservation and consumption reduction: cyclohexanol technology by Tianli has achieved significant energy conservation by comprehensively and cyclically utilizing production resources and adopting energy-saving processes and equipment, thereby reducing the consumption of raw materials and energy.