Propylene and nitrogen

In the temperature range 120-174°C., 3,3 -dimethyldiazirine decomposes at a reasonable rate to give only propylene and nitrogen by a... 

Reagents. Propylene and nitrogen are purified-and dried by a treatment on molecular sieves and finely dispersed metallic copper. The hexane used to suspend the catalyst is distilled and treated the same way. High purity hydrogen is used without additional treatment. 

Figure 21.6 Hybrid compression-condensation membrane separation system to recover liquid propylene and nitrogen from a mixed-gas feed.

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). 

A removal efficiency of 95% is attainable with high inlet gas concentrations. However, the minimum concentration of organic compounds obtained in the outlet gas effluent is equal to the saturation concentration at the operation temperature. Chilled water, brine, refrigerant propylene, and liquid nitrogen can be used as coolants. 

Angell (1) has investigated the Raman spectra of acetonitrile, propylene, and acrolein on a number of zeolites and found that physical adsorption occurred. There are sufficient differences between the spectrum of the liquid and of the adsorbed species (e.g. the carbon-carbon double bond stretching in the case of propylene and the carbon-nitrogen triple bond stretching in the case of acetonitrile) to make it quite clear that it was not merely a case of condensation in the pores of the solid adsorbent. 

From the quench scrubber (B) the gas passes to an absorption column (C) in which the acrylonitrile is absorbed in water to produce a 3 wt per cent solution. The carbon dioxide, unreacted propylene, oxygen, nitrogen and unreacted hydrocarbons are not absorbed and are vented to atmosphere from the top of column (C). 

Polymerization units convert olefin feedstocks (primarily propylene) into higher octane polymers. These units generally consist of a feed treatment unit (to remove H2S, mercaptans, and nitrogen compounds), a catalytic reactor, an acid removal section, and a gas stabilizer. The catalyst is usually phosphoric acid, although sulfuric acid is used in some older methods. The catalytic reaction occurs at 150-224°C (300-435°F) and at a pressure of 11.2-137.0 atm (150-2000 psig). The temperature and pressure vary with the subprocess used. 

Seo, Y.-T. Kang, S.-P. Lee, H. (2001). Experimental determination and thermodynamic modeling of methane and nitrogen hydrates in the presence of THF, propylene oxide, 1,4-dioxane and acetone. Fluid Phase Equilibria, 189, 99-110. 

A VaporSep system recovered approximately 91% of the hydrocarbons from a waste stream of hydrogen, nitrogen, propane, propylene, and water. The capital costs for the system were 2.4 million. By recycling the hydrocarbons and nitrate (permeate and filtrate), the system saved 2.3 million per year (D205549, p. 9). 

Much the same happens if the prepolymers contain basic (tertiary) amino groups—e.g., diols based on primary amines extended with propylene and ethylene oxide and similar materials. The amine nitrogen reacts with the oxidizer, releasing ammonia, and is itself converted to the ammonium ion. Ensuing ionic interaction raises the viscosity of the batch to the point where it becomes unmixable (see also later section on moisture embrittlement). 

Catalytic Experiment. The alkylation of meta-diisopropylbenzene with propylene was performed at 463 K in a flow-type fixed-bed reactor. The carrier gas nitrogen was first saturated with the vapor of meta-diisopropylbenzene (97 %, Aldrich) and then admixed with propylene (99 %, Matheson). The partial pressure of propylene and meta-diisopropylbenzene was 42.6 and 6.0 Torr, respectively. (The molar ratio of propylene and meta-diisopropylbenzene at the reactor inlet was 7.1 1). The modified residence time of propylene and meta-diisopropylbenzene W/Fpr0pyiene and W/Fm DiPB ranged from 4 to 20 and from 25 to 150 gh/mol, respectively, where W indicates the weight of dehydrated catalyst at 623 K and Fi indicates the molar flow rate of reactant i at the reactor inlet. The reaction conditions, viz. the reaction temperature, amount of catalyst, partial pressure and modified residence time of reactants, were chosen in order to obtain conversions of meta-diisopropylbenzene around 25 %. 

Copolymerization of Propylene and Acrylonitrile. Into a threenecked, round-bottomed flask equipped with a thermometer, Teflon-coated magnetic stirrer bar, reflux condenser, and gas inlet and outlet were added 30 ml. of toluene and 2 grams of distilled acrylonitrile. Nitrogen was bubbled through the solution, and all reactions were carried out under a nitrogen atmosphere. 

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