Acidic Hydrocarbons Evolving

SAFETY PROFILE A corrosive irritant to the skin, eyes, and mucous membranes. A strong acid. Violent reacdon with acyl chlorides or aromadc hydrocarbons evolves toxic hydrogen chloride gas. When heated to decomposidon it emits toxic fumes of P and SOx. See also FLUORIDES. 

Acidic hydrocarbons react with Ca, Sr and Ba metal in polar solvents with cleavage of carbon—hydrogen and formation of carbon—M bonds e.g., Ca reacts with CjHg in tetrahydrofuran (THF) in which Hj evolves and (CjHjljCa is formed as a THF complex ... 

Detection of the Paraffins.—The identification of the paraffins is difficult on account of the lack of definite analytical tests. The paraffins are characterized by their inertness. They can be shaken with fuming nitric acid without appreciable change. They are insoluble in concentrated sulphuric acid and are not attacked by it. The liquid hydrocarbons react slowly with bromine a solution of the halogen in the hydrocarbon retains its color for some time. As reaction takes place hydrobromic acid is evolved. The hydrocarbons are insoluble in water and float. They dissolve in alcohol and benzene. 

The peroxidative reactions were mediated and sustained by Cu(II) ions in the light. Table IV shows that fatty acids with at least 2 double bonds are necessary for hydrocarbon formation. As Anacystis lacks those fatty acids, no peroxidative volatile hydrocarbons were produced. Spirulina exclusively contains CO-6 fatty acids as endogenous polyunsaturated fatty acids and evolved Cs hydrocarbons only. The third species, Anabaena, whose thylakoids contain co-3 and Co-6 polyunsaturated fatty acids formed C2 and C5 hydrocarbons simultaneously. We conclude that co-3 polyunsaturated fatty acids are the source of ethane and ethylene and that the CO-6 polyunsaturated fatty acids are the source of pentane and pentene in herbicide-induced peroxidation reactions. Furthermore, we obtained evidence that the propane measured with Bumilleriopsis after an 18-h treatment with either 10 >iM oxyfluorfen or 50 jxM Cu(II) originates from a CO-4 polyunsaturated fatty acid. We have recently isolated and identified this acid as 16 3CO4 (Sandmann, Lambert, B5ger in preparation). 

Precaution Strong acid violent reaction with acyl chlorides or aromatic hydrocarbons, evolving toxic hydrogen chloride gas... 

Toxicology Corrosive irritant to skin, eyes, mucous membrane TSCA listed Precaution Strong acid violent reaction with acyl chlorides or aromatic hydrocarbons, evolving toxic hydrogen chloride gas Hazardous Decomp. Prods. Heated to decomp., emits toxic fumes of F and SOx Storage Hygroscopic... 

In this method, solutions of organomagnesium derivatives are analyzed by hydrolysis with concentrated phosphoric acid in a microreactor and passing the hydrocarbons evolved through a bypass injector into a gas-chromatographic apparatus (with an activated silica-gel column, for - C3 hydrocarbons). Concentrations of alkyl groups are then calculated from the peak areas in the usual way. 

Metallic sodium. This metal is employed for the drying of ethers and of saturated and aromatic hydrocarbons. The bulk of the water should first be removed from the liquid or solution by a preliminary drying with anhydrous calcium chloride or magnesium sulphate. Sodium is most effective in the form of fine wire, which is forced directly into the liquid by means of a sodium press (see under Ether, Section II,47,i) a large surface is thus presented to the liquid. It cannot be used for any compound with which it reacts or which is affected by alkalis or is easily subject to reduction (due to the hydrogen evolved during the dehydration), viz., alcohols, acids, esters, organic halides, ketones, aldehydes, and some amines. 

Place a mixture of 1 0 g. of the hydrocarbon, 10 ml. of dry methylene chloride or ethylene dichloride or syw.-tetrachloroethane, 2 5 g. of powdered anhydrous aluminium chloride and 1-2 g. of pure phthalic anhydride in a 50 ml. round-bottomed flask fitted with a short reflux condenser. Heat on a water bath for 30 minutes (or until no more hydrogen chloride fumes are evolved), and then cool in ice. Add 10 ml. of concentrated hydrochloric acid cautiously and shake the flask gently for 5 min utes. Filter oflf the solid at the pump and wash it with 10-15 ml. of cold water. Boil the resulting crude aroylbenzoic acid with 10 ml. of 2 -5N sodium carbonate solution and 0 2 g. of decolourising carbon for 5 minutes, and filter the hot solution. Cool, add about 10 g. of crushed ice and acidify... 

The procedure is to pass purified hydrogen through a hot solution of the pure acid chloride in toluene or xylene in the presence of the catalyst the exit gases are bubbled through water to absorb the hydrogen chloride, and the solution is titrated with standard alkali from time to time so that the reduction may be stopped when the theoretical quantity of hydrogen chloride has been evolved. Further reduction would lead to the corresponding alcohol and hydrocarbon ... 

Fuming sulphuric acid test. Place 2 ml. of 20 per cent, fuming sulphuric acid in a dry test-tube, add 0 -5 ml. of the hydrocarbon and shake vigorously. Only the aromatic hydrocarbon dissolves completely heat is evolved, but excessive charring should be absent. 

Peculiar reactions occur during the oxidation of organic acid anions. In 1843, M. Faraday found that a hydrocarbon is evolved during the electrolysis of acetate solutions. These reactions were studied in 1849 by Hermann Kolbe, who showed that the acetate ions during electrolysis condense with the evolution of COj that is, the reaction (in modem notation)... 

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