Calcium unsaturated hydrocarbons

All hydrocarbons prepared by th -. Wurtz reaction contain small quantities of unsaturated hydrocarbons. These may be removed by shaking repeatedly with 10 pier cent, of the volume of concentrated sulphuric acid until the acid is no longer coloured (or is at most extremely pale yellow) each shaking should be of about 5 minutes duration. The hydrocarbon is washed with water, 10 pier cent sodium carbonate solution, water (twice), and dried with anhydrous magnesium or calcium sulphate. It is then distilled from sodium two distillations are usually necessary... 

Electrophoretic mobility and 31P-NMR measurements were made to investigate the binding of the alkaline earth cations to membranes formed from phosphatidyl choline molecules with either saturated or unsaturated hydrocarbon chains. Calcium and magnesium bind to the same degree to membranes formed from lipids with unsaturated chains. These phosphatidylcholine molecules are present in the liquid crystalline state at all temperatures under consideration. Calcium binds more strongly than magnesium to membranes formed from lipids with saturated chains, even when the lipids are in the liquid crystalline state. The selectivity is enhanced when the temperature is lowered and the saturated chain lipids are in the gel state. 

Sodium forms of zeolites X and Y are known to be Inactive for alkylation. Calcium Introduction (catalyst 1) has resulted In a catalyst with some activity. Selectivity of the sample was not high about 57% of the alkylate were octanes with a ratio of TfV to DW of 2 1. The yield and quality of the alkylate were Improved, If Na" " cations were replaced with cations of rare-earth elements (catalysts 2 and 3). Product yield for catalysts 2 and 3 were 86.0% and 77.5% respectively with a TMP content In C0-fractionof about 85%. Unfortunately the stabilities of these two catalysts were rather low In both cases, and alkylates yields and quality declined after 3 or 4 runs. For example the percentage of unsaturated hydrocarbons In the hydrocarbon product for catalyst 3 Increased from 18 up to 30%, and TMP concentration decreased to 35% after several runs. Catalyst 4 has proved to be the most active and stable catalyst and the yields and quality of alkylates obtained over It have been the same even after many reaction-regeneration cycles. Further Increase of calcium content In the catalyst (catalyst 5) deteriorated Its catalytic properties. 

For ethane, adsorption values of 4.04 wt% for DD3R were found while Na-A adsorbs 7.4 wt% at similar conditions (700 Torr, 25°C), so DD3R adsorbs 54.6% of the amount of ethane adsorbed on zeolite A. The accessible volume of DD3R is 0.48% compared with zeolite A, so based on the void volume, both materials show comparable adsorption of a non-polar molecule. The adsorption of ethylene amounts to 43.5 %, compared to zeolite A (3.65 wt% and 8.4 wt%, respectively). The slightly higher preference of zeolite A for an aUcene can be ejqrlained in terms of stronger interactions of an unsaturated hydrocarbon with the ionic nature of the zeolite A surfece. Calcium-exchanged type A zeolites were found to exhibit the same behaviour firr propane and propylene [38]. 

Place in an eight-inch tube 5 ml of the unsaturated hydrocarbon and 5 ml of cold 70 per cent sulfuric acid. Cool the mixture in tap water, place a solid rubber stopper in the mouth of the tube, and shake with cooling until the hydrocarbon dissolves and a clear liquid results. Add 6 g of ammonium sulfate dissolved in 8 ml of water. Insert the separatory stopper, and remove the aqueous acid layer. The liquid which is left in the reaction tube can be tested with bromine water or alkaline permanganate to show that it is not an olefin. If it is desired to purify the alcohol, add 1 g of anhydrous calcium sulfate and shake from time to time over a period of fifteen minutes. Pour the crude alcohol into a distilling tube. Heat with a small flame and collect the proper fraction. If amylene is used, and the water is not completely removed by the drying agent, a constant boiling mixture will be formed which boils at 87°. 

Sfslinene has a specific gravity 0"919, optical rotation + 61 36, refractive index 15093, and boiling-point 128° to 132 at 11 mm. It is shown to be a hi cyclic doubly unsaturated hydrocarbon. On reduction it yields tetrahydrO-aelincne, Cj H of specific gravity 0 688l, rotation -t- 7°, refractive index 1 48259 and boiling at iSd"" to 128° at 11 mm. Selinene yields a dihydrochloride which, when treated with calcium hydroside, yields the alcohol selinenol This body boils at... 

It follows from this discussion that all solvents and monomers used must be carefully purified. Hydrocarbons should be stirred over sulphuric acid for many days and ethers refluxed over sodium—potassium alloy or sodium fluorenone before fractionation. Traces of unsaturated materials in aliphatic hydrocarbons can be removed by silica gel. After fractionation, a preliminary drying over calcium hydride can be followed by storage over sodium—potassium alloy for ethers, or a treatment with butyllithium or similar non-volatile reactive organometallic reagent for hydrocarbons. Monomers cannot be treated quite so drastically, but fractionation followed by a pre-polymerization in vacuum over butyl-... 

Introduction. Acetylene has the empirical formula C2Hs. It shows a greater unsaturation than ethylene, in that it can add four univalent groups to each carbon atom. This xmsaturation is indicated by a triple bond between the two carbon atoms HC=CH. Acetylene is produced in the thermal decomposition of many hydrocarbons. Of theoretical interest is its formation from hydrogen and carbon in the electric arc. It is prepared industrially by the pyrolysis of methane, and by the action of water on calcium carbide. The last method is employed for preparation of small quantities in the laboratory ... 

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