Acrylonitrile Analysis

Production of Acrylonitrile using Ammoxidation of Propylene

Almost 90% of world production of acrylonitrile (AN) was produced by ammoxidation of propylene process also known as SOHIO process (Standard oil of OHIO). The main chemical reaction and the side reaction occurred in ammoxidation process happen as listed below:

Main Chemical reaction:

C_3 H_6+ 〖NH〗_3+ 〖3⁄2 O〗_2 → C_3 H_3 N+ 〖3H〗_2 O

Propylene+Ammonia+Oxygen →Acrylonitrile+Water (1)

Side Reaction:

C_3 H_6+ 〖NH〗_3+ 〖9/4 O〗_2 → C_2 H_3 N+ 〖3H〗_2 O+ 〖1/2 CO〗_2+1/2 CO

Propylene+Ammonia+Oxygen→Acetonitrile+Water+Carbon dioxide+Carbon monoxide

(2)

C_2 H_3 N+ 〖3/2 O〗_2 → HCN+ H_2 O+ 〖CO〗_2

Acetonitrile+Oxygen →Hydrogen Cyanide+Water+Carbon dioxide

(3)

Combustion

Starting with advantages of using this method with the main key point is the lesser fuel usage for the catalytic oxidation process. Next the catalyst employed in this reaction has high activity for the production of unsaturated nitrile and can be use in lower reaction temperature. Furthermore it has stable redox stability under the reaction condition of the process. By using the circularly fluidized bed reactor (CFB) its help to produce high yield product by separating the catalyst reduction zone and the re-oxidation process and it can be controlled independently. Methodology process can be more simplified for adding and removing catalyst using this type of reactor. The concentration of feed gas can be higher above the explosion to produce higher concentration of the

This is highly exothermic reaction with the present of multi component catalyst such as molybdenum, bismuth and iron supported by silica. These catalysts can achieve high selectivity and weak activity that deactivate the process slowly. The drawback using these catalysts is the product is easily poisoned by sulfur compound in the reactant gas. Because of the highly exothermic reaction, it can achieve until 670 to 750 kJ/mol of heat reaction. The superficial velocity of reactant gas inserted into the reactor is very fast by the range of 0.4 to 0.7 m/s and it only taken few seconds of contact time from 5 to 20s in the reactor. Ratio for the gas feed into the fluidized bed reactor by the composition of C3H6: NH3: O2 is 1: 1-1.2: 10-12. The reactor are fed with slightly excess of ammonia of stoichiometry proportion to get the reaction closer to completion and fastening the process of catalyst regeneration. Ammoxidation of propylene give higher conversion till 98% and the selectivity above than 80%. Byproduct produces from this reaction by weight percentage (% wt) base on acrylonitrile are acetonitrile 2-4 % and hydrogen cyanide 14 to 18 %. This byproduct can be market for any other purposed and there are still demands in the chemical industry. The reaction product will be absorb in