Acetonitrile is produced by acetic acid ammonification
The main use of acetonitrile is as a solvent, such as extraction of butadiene, isoprene extraction agent, synthetic fiber spinning solvent and some oils, phenols and non-ferrous substances solvent; Used in the oil industry as a solvent for extracting fats from vegetable oils; Used in medicine as a reaction medium for recrystallization of steroidal drugs. Acetonitrile is also medicine (vitamin B1), flavor intermediate, is the preparation of 2-methylpyridine, triazine, ethylamine, dipropyl nitrile, imidazole, propyl diacetonitrile and other raw materials.
In the traditional process of acetonitrile synthesis and refinement by acetic acid ammoniation, acetonitrile is prepared by the ammoniation reaction of acetic acid and ammonia in reaction kettle under the catalyst of aluminum oxide. After the reaction, the crude product body contains acetonitrile, water and a small amount of ammonia. After the ammonia is absorbed and removed by the two-stage absorption tower, it is successively taken into the concentration tower, negative pressure tower and positive pressure tower to obtain the finished acetonitrile.
Since acetonitrile and water will form azeotrope (the water content of acetonitrile and water azeotrope is about 16 wt.% under normal pressure), it is impossible to directly refine the acetonitrile mother liquor in the absorption section into finished acetonitrile by conventional distillation method (the water content of refined acetonitrile is usually ≤0.1 wt.%). At present, one concentrated column, one negative pressure column and one positive pressure column are used in acetonitrile synthesis by acetic acid ammonification. The steam consumption of this kind of process is large, the equipment occupies a large area, the process flow is long, the amount of material and liquid circulation is large, the operation is complicated, and the yield of acetonitrile is low.
The traditional process
The new process
The new technology developed by ninday high technology co., ltd. has high recovery rate, simple process, high safety factor, high energy utilization rate, small material and liquid circulation amount, low operating energy consumption (4t/t steam consumption in traditional process, 1.6~2t/t in new process), and no third component.
The engineering case
Shandong huihai, nantong liyang
Shandong huihai 10,000 tons/year acetonitrile plant
Acetone is hydrogenated to produce isopropanol
Isopropanol is an important chemical product and raw material, which is widely used. China is the largest import country of isopropanol in Asia. At present, the annual output of isopropanol in China is about 160,000 tons. Because the production of isopropanol is restricted by raw material supply, production technology, environmental protection and other factors, the annual domestic output is far less than the annual market demand. Imports of isopropanol were 115,000 tons in 2010 and 100,000 tons in 2011. The direct water method of propylene is the main method to produce isopropyl alcohol in industry. It is to produce isopropyl alcohol and n-propyl alcohol by side under the direct hydration reaction of propylene in the presence of catalyst. Due to the shortage of domestic propylene resources, the propylene consumption, energy consumption and production cost of isopropanol produced by propylene hydration process are very high. In contrast to propylene, the domestic acetone production capacity is large, the market volume is rich, the price is low. Industrial acetone is almost exclusively obtained by the isophenol peroxidation process (combined with phenol). Due to the increase of demand for phenol, a large amount of acetone is produced in combination with the imbalance of demand, which often leads to the situation of excessive acetone. As a result, the price of acetone is lower than that of isopropyl alcohol and propylene. Therefore, the development of acetone hydrogenation technology to produce isopropyl alcohol has a broad application prospect.
In the process of acetone hydrogenation to produce isopropanol, there is a small amount of side reaction. The side reaction products mainly include water, diisopropyl ether, diacetone alcohol and 4-methyl pentanol, etc. These side products need to be separated in the subsequent process of isopropanol refining. Two distillation columns are used to separate isopropanol. The by-product water and a small amount of unreacted acetone were removed from the top of the first tower, and isopropyl alcohol and other recombinant by-products were obtained from the tower kettle. The isopropyl alcohol products with water content <0.03wt.% were obtained from the top of the second tower, and the remaining recombinant products were removed from the tower kettle. With isopropyl alcohol and water, acetone forming ternary azeotrope (acetone 8 wt. %, isopropyl alcohol 81 wt. %, water 11 wt. %), the traditional azeotropic distillation and extractive distillation separation dehydration process complex, high cost and environmental pollution is serious, makes the manufacturer generally will be sold as waste liquid, resulting in decreased isopropyl alcohol yield, production cost is too high.
The production process
Typical engineering cases
Yancheng supur chemical 8000t/year isopropanol/acetone/water membrane device