Propylene-nitrogen oxides-sulfur

The reverse-flow chemical reactor (RFR) has been shown to be a potentially effective technique for many industrial chemical processes, including oxidation of volatile organic compounds such as propane, propylene, and carbon monoxide removal of nitrogen oxides sulfur dioxide oxidation or reduction production of synthesis gas methanol formation and ethylbenzene dehydration into styrene. An excellent introductory article in the topic is given by Eigenberger and Nieken on the effect of the kinetic reaction parameters, reactor size, and operating parameters on RFR performance. A detailed review that summarizes the applications and theory of RFR operation is given by Matros and Bunimovich. 

Compounds considered carcinogenic that may be present in air emissions include benzene, butadiene, 1,2-dichloroethane, and vinyl chloride. A typical naphtha cracker at a petrochemical complex may release annually about 2,500 metric tons of alkenes, such as propylenes and ethylene, in producing 500,000 metric tons of ethylene. Boilers, process heaters, flares, and other process equipment (which in some cases may include catalyst regenerators) are responsible for the emission of PM (particulate matter), carbon monoxide, nitrogen oxides (200 tpy), based on 500,000 tpy of ethylene capacity, and sulfur oxides (600 tpy). 

Dithiophosphates. These compounds (13) are made by reaction of an alcohol with phosphoms pentasulfide, then neutralization of the dithiophosphoric acid with a metal oxide. Like xanthates, dithiophosphates contain no nitrogen and do not generate nitrosamines during vulcanization. Dithiophosphates find use as high temperature accelerators for the sulfur vulcanization of ethylene—propylene—diene (EPDM) terpolymers. 

Nitrogen was bubbled for five minutes through a solution of 2.0 g (8.9 mmol) of 1.1.12a and 5 mL of propylene oxide in 100 mL of aq. acetone (acetone/water, 95 5). The solution was irradiated (Rayonet photoreactor RPR 208, X = 300 nm) for 4 h. After rota-evaporation of the solvent, the residue was dissolved in ether and extracted with 5% sodium bicarbonate solution. The alkali extract was then cooled and acidified with dil. sulfuric acid. Extraction of the separated oil in ether and concentration of the ether layer gave a solid which was crystallized from petroleum ether to yield 1.28 g (70%) of 1.1.12b, mp 76 -77 °C. 

To a 1-liter stainless steel autoclave are added 230 gm (0.8 mole) of stearyl alcohol and 0.9 gm of sodium methoxide powder. The reactor is purged with nitrogen. Then 408 gm (7.0 mole) of propylene oxide is added over a 16-hr period while the temperature is kept at 130°-135°C. After the reaction is complete the mixture is cooled and the volatiles are eliminated by heating on a water bath for 15-20 min. Then dilute sulfuric acid is added to neutralize the catalyst and the product is washed with 1 liter of water at 60°C, followed by two washings with 500 ml of water at 60°C. The product is dried imder reduced pressure to give 548 gm (99%) of a light-yellow product having a hydroxyl number of 94. 

To a 1-liter, three-necked, round-botton flask equipped with a mechanical stirrer, reflux condenser, thermometer, and addition funnel is added 57 gm (0.75 mole) of propylene glycol and 7.5 gm (0.19 mole) of sodium hydroxide. The flask is purged with nitrogen to remove air and heated to 120°C with stirring to dissolve the sodium hydroxide. Then propylene oxide is added (40-45 mole). The reaction mixture is cooled under nitrogen, neutralized with dilute sulfuric acid, filtered, and dried under redueed pressure to give a water-insoluble product with MW 1620 as determined by hydroxyl number or acetylation analytical procedures. 

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