Catalytic Synthesis of Acetonitrile by Ammonolysis of Acetic Acid

S.I Galanov,V.D Philimonov,O.I Sidorova,L.N Kurina,E.A Rozhdestvenskiy,A.K Golovko

doi:10.18321/ectj562

Abstract

The influence of principal parameters (reagent ratio, reaction temperature, temperature gradients along a catalyst layer) on the yield of the desired product was studied in the reaction of acetonitrile synthesis from acetic acid over γ-alumina. Thus, the increase in ammonia:acetic acid ratio leads to the increase in acetonitrile selectivity and yield. In this work it has been demonstrated that initial temperatures of 360-380 °C are optimum to effectively carry out the process of acetonitrile synthesis. The increase in reaction temperature allows one to increase the yield of acetonitrile, but at elevated temperatures the catalyst carbidization and contamination of the desired product were observed. The additives to the reaction mixture of the substances that decrease the rate of compaction products (CP) formation and participate in the desired product formation are very effective for decreasing the catalyst carbidization. The effect of the composition of a reaction mixture on a catalyst lifetime is considered. The addition of ethyl acetate to acetic acid promotes a greater carbidization as compared to pure acetic acid. The application of a mixture of acetic acid with acetic anhydride at similar acetonitrile yield decreases the catalyst carbidization.

Highlights

Acetonitrile is widely used in organic synthesis as an intermediate reagent, solvent, azeotropizer [1,2]
The reaction of acetonitrile formation from acetic acid and ammonia occurs at several stages [3, 4]: I
One of the methods for decreasing the catalyst carbidization is the introduction of water vapours to the reaction mixture, as noted in [3, 4], the application of diluted acetic acid results in the reduction in acetonitrile yield and catalyst efficiency

Summary

Introduction

Acetonitrile is widely used in organic synthesis as an intermediate reagent, solvent, azeotropizer [1,2]. The reduction in the acid load (increase in contact time) from 1.02 to 0.58-0.67 g/cm3·h at the increase of acetonitrile yield (Table 1) leads to a decrease in efficiency from 0.57 to 0.4-0.46 g of acetonitrile per cm3 of a catalyst·hour, in this case a side reaction of acetic acid decomposition is observed followed by acetone formation.

Results

Conclusion