# US 4,394,220 A · Process for rectification of propane nitration stream

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- Number: US 4,394,220 A
- Document ID: US4394220A
- Status: Granted
- Kind: A
- Application number: 06/313,862
- Filed: 1981-10-22
- Granted: 1983-07-19
- Earliest claimed: 1980-09-02
- Assignees: Angus Chemical Company
- Inventors: Richard S. Egly; Cecil E. Turnquist
- Web page: https://patentgrep.com/patent/US4394220A

## CPC

- C07C 201/16: Separation; Purification; Stabilisation; Use of additives
- B01D 3/40: Extractive distillation
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)

## Abstract

It is the discovery of the present invention to provide an improved method of rectifying the crude production stream obtained by the vapor phase nitration of hydrocarbons by subjecting the absorber bottom mixture to extractive distillation with water.

## Claims

### Claim 1

In a method for rectifying the crude production stream obtained from the process of vapor phase nitration of hydrocarbon to produce nitroalkanes, which includes passing the vapor phase nitration stream from a nitration chamber through a condenser to condense a substantial portion of the normally-liquid components and separate said normally-liquid components from normally-gaseous components, forming absorber bottoms by passing the gaseous components into a water absorber to wash the gas, said absorber bottoms including nitroalkanes, acetaldehyde, nitrogen, nitrogen oxides and oxygenated compounds, stripping the condenser liquid and absorber bottoms by distillation to form a condensate including a water layer and an oil layer, said oil layer comprising crude nitroalkanes and low boiling components, stripping the low boiling components from the condensate in a heads column, and fractionating the oil layer to produce fractions of nitroalkane components, the improvement comprising, subjecting the condenser liquid and absorber bottoms solely to extractive distillation with substantially pure water to remove sufficient impurities therefrom so that the condensate is relatively free of impurities, thereby avoiding carbonaceous build-up in the heads column and fractionater during extraction of the nitroalkanes.

### Claim 2 (depends on 1)

The method of claim 1 wherein the water used for extraction is used in a volume of about 1 part of liquid to one part of nitroalkane vapors.

### Claim 3 (depends on 1)

The method of claim 1 wherein the water used for extraction is used in a volume of about 2.5 parts of liquid to one part of nitroalkane vapors.