Property and Preparation of n-Propyl Nitrate

N-propyl nitrate is also called as n-propyl alcohol nitric ester. 

Al-propyl nitrate is a flammable liquid with boiUng point of 110.5 °C and density of 1.063. Its explosive property is not severe, thus that it is difficult to be detonated. The calculated explosion heat is 549 kcal/kg (water vapor). The lead-block value after rectification of the detonator is only 15 cm. The explosion limit of the mixture with air is 2-100 %. Its flash point is 20 °C and the ignition point in air is 176.7 °C. Its vapor, which is heavier than air, can spread around and be ignited by distant fire. Furthermore, the ignition flame would be returned to the -propyl nitrate source. Being heated, M-propyl nitrate would be exploded. A significant detonation could be happened if it mixes with diatomaceous earth with ratio of 71.5/28.50. The lead-block value is 230 cm. A/-propyl nitrate can be used as a sensibilizer in cloud detonation, a rocket propellant, and a promoter of cetane number for diesel oil. 

Hinkamp et al. [55] prepared n-propyl nitrate with a yield of 66.5 % by using mixture acids of 20 wt% HNO3, 68 wt% H2SO4, and 12 wt% H2O. For this preparation method, the yield is low and acid mist could be formed for environmental pollution in the process of waste acid treatment by sulfuric acid method. People [56] improved the M-propyl alcohol nitration on the nitrating agent and the 

The writer [15,57] addressed a method to prepare n-propyl nitrate. In a reactor, a mixture of 68 % nitric acid and urea was added to vapor temperature of 98 °C. At the moment, the temperature of the liquid surface was 112 °C and the temperature of the oil bath was 142 °C. The 68 % nitric acid solution and the n-propyl alcohol solution with water and 5 % urea were dropwisely added into the reactor. At the beginning of the addition, the temperature of the distillates was 98-106 °C. In the steady state, the vapor temperature was 102-104 °C with the temperatures of liquid surface of 110 °C and the oil bath of 145 °C. The addition was finished in 90 min and the reactor was kept warm for another 15 min. The cmde products with yield of 89 % was successively water-washed and alkaline-washed (1.5 % sodium carbonate) to pH 7 and oil-water separation. Anhydrous magnesium sulfate was added to the oil part for 24 h. After filtration, the crude product was then rectified and the final product was obtained from the cut of 109.5-110.5 °C with a yield of 86.3 % and purity of 99.62 %. 

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