Continuous Process For Production of 2,2-Dinitropropane

Abstract

381general unit operations equipment such as filter presses, pumps, and centrifugals, which can be adapted to almost any unit process. Here the fundamental chemical changes are initially applied and the equipment is checked for proper design and adaptability to the economic factors of a specific industry.To stimulate further research and also to enable practicing chemical engineers to make better use of the present state of knowledge, INDUSTRIAL AND ENG~NEERINQ CHEMISTRY is now organizing a yearly review of unit processes, the first of which is scheduled to appear in the early fall. This presentation will be by a group of men experienced in the particular unit process dis-THE data presented here show that, by operating at the proper conditions, 2-nitropropane can be nitrated with nitric acid to give 2,2-dinitropropaneY a valuable combustion modifier for Diesel fuels. Optimum conditions are: pressure, 990 to 1200 pounds per sqpare inoh; temperature, 400' to 450' F. (204-232' C.); molar ratio, 1 mole of nitric acid to 1 mole of 2-nitropropane when using 70% nitric acid; space velocity, 1.0. Conversions per pass of 11 to 14 mole YO of the 2-nitropropane charged are obtained under these conditions with ultimate yields above 50%. For commercial exploitation more detailed yield and corrosion data are necessary.H E observation that 2,2-dinitropropane is an extremely T effective combustion modifier for Diesel fuels (6, 6) stimulated efforts to find a direct and economical method for its preparation. The recent commercial availability of 2-nitropropane made it appear a likely starting material for the synthesis of 2,2-dinitropropane. This paper presents data on a process for the production of 2,2-dinitropropane from 2;nitropropane.The vapor phase nitration of paraffin hydrocarbons as reported by Hass and co-workers ( 1 , s ) produces all possible mononitro pro'ducts of the starting paraffin plus all the mononitro products of a degradation series of the paraffin. However, substantially no polynitro paraffins are produced.Urbanski and Slon (7) nitrated propane with nitrogen tetroxide at'temperatures above 100' C. They report the formation of 1-nitropropane (boiling point indicates it was fl-nitropropane) and 1,3-dinitropropane but no 2,2-dinitropropane. Hass, Dorsky, and Hodge (9) nitrated propane a t 248' C. with nitrogen dioxide. Although various mononitro paraffins were produced, no polynitro paraffins were formed.Konowalow (4) states that dinitro compounds might be formed by the action of nitric acid on mononitro compounds but restricted his work to compounds having more than five carbon atoms. Gem-dinitro compounds were not among the dinitro compounds described by him.Since vapor phase nitration produced cracking as shown by = that nitration at a lower temperature would be necessary t o preserve the length of the carbon chain. It also appeared advisable t o maintain a 1.iquid phase or a borderline liquid-vapor phase by the use of elevated pressures, as liquid-phase nitration seems t o favor polynitration.The preliminar...

Taming hazardous chemistry by continuous flow technology

“…121 Already during World War II, nitration was conducted in a continuous flow reactor. 122,123 Continuous systems were developed and patented for the synthesis of explosive materials such as nitroglycerine, ethylene glycol dinitrate, diethylene glycol dinitrate, cyclotrimethylenetrinitramine and pentaerythritol tetranitrate. 122 The experimental setup for continuous flow nitrations covered in literature typically exists of two feeds, containing the substrate and the nitrating agents, a micromixing device in a thermal bath at a constant temperature and a controlled residence time.…”

Continuous flow nitration in miniaturized devices

“…3.1.3 Vapour phase nitration. In an early study on the continuous flow nitration of 2-nitropropane ( 52 ), Denton et al [ 22 ] demonstrated that high pressure and high temperature conditions, i.e., 900 to 1200 psi and 203–232 °C, using an equimolar nitric acid (70%) gives about 50% yields per pass ( Scheme 15 ). Their reaction assembly consists of a stainless steel preheater tube (outer diameter of 6.24 mm) passed through a 40 inch long 20 mm outer diameter.…”