Property and Preparation of Isopropyl Nitrate

Isopropyl nitrate, also called as isopropanol nitrate ester, is an isomer of n-propyl 

The preparation method of isopropyl nitrate is different from that of n-propyl nitrate. Because of the boiling point, the relative density of 1.036, and the secondary hydroxyl groups, the direct nitration is relatively difficult. In the early literatures, it was believed that isopropyl nitrate only can be obtained from 

2-iodopropane and silver nitrate [58], In British patent [55], isopropanol was continuously nitrated in urea. At the temperature of the boiling point of nitric acid, isopropanol and urea were added into nitric acid with concentration of over 40 %. Unstable products were removed by a flowing gas. The theoretical yield of isopropyl nitrate obtained by this method is 80 % [59]. The main methods to prepare isopropyl nitrate include (1) sliver nitrate-alkyl halide reaction, (2) nitration by the mixed acids of nitric acid and sulfuric acid, and (3) inert adsorption nitration [60, 61]. Based on those preparation methods. The writer [15, 62-64] invented the dual inert complementary adsorption nitration. In the method, the concentration of nitric acid is over 50 % and the reaction temperature is 108-110 °C. Commercial production of isopropyl nitrate has been done by this method. A certain amount of urea and ammonium nitrate is used in the method to absorb nitrogen oxides, which will be oxidized to isopropyl nitrate. The isopropyl nitrate would be catalytically hydrolyzed at high temperature. The reaction mechanism can be expressed as the following equation. 

The inert adsorption nitration is suitable for commercial production of isopropyl nitrate because of its features, such as simple procedure, cheap raw materials, low-cost production, and easy treatment of waste acid. The procedure is described below. 

In order to study the relationship between the reaction condition and yield, the writer [63, 65] investigated the effects of urea amount, ammonium nitrate amount, concentration of nitric acid, the addition time of isopropanol, the feeding system, and feed types on the yield of isopropyl nitrate. The effect of urea amount on the yield of isopropyl nitrate is summarized in Table 5.6, under the reaction condition 

---