Acetylenic 18-carbon acids

Recent syntheses of unsaturated fatty acids that differ systematically in alkyl chain structure (9, 10) make it possible to study the influence of unsaturation on a number of chemical and biochemical processes (11). It seemed to us that many questions concerning the influence of alkyl chain structure on fatty acid interfacial properties could be answered better by studying the monomolecular film properties of these compounds. This paper examines the general surface film properties of some cis and trans ethylenic and acetylenic 18-carbon acids. 

Reppe s work also resulted in the high pressure route which was estabUshed by BASF at Ludwigshafen in 1956. In this process, acetylene, carbon monoxide, water, and a nickel catalyst react at about 200°C and 13.9 MPa (2016 psi) to give acryUc acid. Safety problems caused by handling of acetylene are alleviated by the use of tetrahydrofuran as an inert solvent. In this process, the catalyst is a mixture of nickel bromide with a cupric bromide promotor. The hquid reactor effluent is degassed and extracted. The acryUc acid is obtained by distillation of the extract and subsequendy esterified to the desked acryhc ester. The BASF process gives acryhc acid, whereas the Rohm and Haas process provides the esters dkecdy. 

The zwitterions (139) (formed by the reaction of the tributylphosphine-carbon disulphide adduct with acetylenic carboxylic acids) undergo hydrolysis to give 1,3-dithioles.133 The products of alkaline hydrolysis of the salts (140) have been investigated.134... 

The Reppe process was commercialized in the 1950s. It involves the reaction pf acetylene, carbon monoxide, and an alcohol (methyl, ethyl, etc.) to give an acrylic ester (an acrylate). The process is carried out at 125°F and 15—30 psi in a nickel carbonyl/aqueous hydrochloric acid solution. The nickel carbonyl acts as both a catalyst and a secondary source of carbon monoxide. 

Acetylene Dichloride Acetylene Tetrachloride Acetylenogen Acetyl Hydroperoxide Acetyl Peroxide Solution Acid Ammonium Carbonate Acid Ammonium Fluoride Acid Calcium Phosphate... 

Later, Kang et al. [35] reported surface modification of carbon black using various monomers like acetylene, acrylic acid, butadiene, and oxygen. They concluded that it is possible to manipulate the surface properties of carbon black using plasma polymerization. 

There is a seemingly endless variety of fatty acids, but only a few of them predominate in any single organism. Most fatty acid chains contain an even number of carbon atoms. In higher plants the C16 palmitic acid and the C18 unsaturated oleic and linoleic acids predominate. The C18 saturated stearic acid is almost absent from plants and C20 to C24 acids are rarely present except in the outer cuticle of leaves. Certain plants contain unusual fatty acids which may be characteristic of a taxonomic group. For example, the Compositae (daisy family) contain acetylenic fatty acids and the castor bean contains the hydroxy fatty acid ricinoleic acid. 

Reaction XXXIV. (c) Action of Carbon Dioxide on Sodium Acetylides in Dry Ether. (B., 12, 853 J. pr., [2], 27, 417 B., 33, 3586.)—This is an example of the great activating influence of a triple bond. When carbon dioxide is passed into a solution of the sodium derivative of an acetylenic hydrocarbon in dry ether, direct addition takes place to give the sodium salt of the next highest acetylenic carboxylic acid. For example, sodium allylene yields sodium tetrolate—... 

The carbon skeleton of the unknown acetylenic amino acid must be the same as that of homoleucine. The structure of homoleucine is such that there is only one possible location for a carbon-carbon triple bond in an acetylenic precursor. 

Ethyl Alcohol.—In an atmosphere of ethyl-alcohol vapors, M. Quet5 and Perrot 6 obtained, besides some carbon, a substance which exploded on being heated, the chemical nature of which they were unable to determine. The liquid became acid but Perrot found that no water was formed in the decomposition of the alcohol he was also unable to prove the presence of carbonic acid gas. Melly 7 and Lommel8 made similar experiments, the latter employed a Holtz machine. The gas escaping in the decomposition of the alcohol probably contains acetylene and ethylene. 

Methyl Alcohol.—According to Maquenne,2 the vapor of methyl alcohol is decomposed by the silent discharge chiefly into methane and carbon monoxide some hydrogen, ethylene, and acetylene and very little carbonic acid, are also produced. The quantity of hydrogen increases with increasing pressure (from 3-100 mm. mercury pressure), that of the other products decreases ... 

Acetic Acid.—Besides hydrogen, carbon mon- and dioxides, Maquenne 3 also obtained methane, ethylene, and acetylene. With increasing pressure he found an increase in hydrogen and carbon monoxide, a decrease in-carbonic acid and hydrocarbons. Hemptinne observed similar results with his experimental arrangement. He accepts the following as the primary decomposition process, corresponding to that of the alcohols ... 

Bomeol, ferf-butyl alcohol d-camphor, cineol, pentamethyl ethyl alcohol Ally) alcohol, cyanogen, formaldehyde, formic acid, methylisothiocyanate Acetylene, carbon tetrachloride, chloroform, ethylene dichloride, propyl alcohol... 

The problems involved in the measurement of acidities or relative acidities of weak acids are illustrated by the widely different estimates which have been given for the acidity of substituted acetylenes. Two different approaches have been used for measuring the equilibrium acidity of carbon acids which do not ionize in the pH range. In one approach, the ionization of a carbon acid is studied in mixed solvents containing base. Some of these solutions are more basic than aqueous solutions and by varying the solvent mixture the ionization of acids with pK values in the range 12—25 can be studied. Values at the low end of the pK range are directly compared with aqueous p/iC values. It is assumed that ratios of the activity coefficients (f) for the ionized (S-) and unionized acids (SH) are the same for all the acids studied and an acidity function (86)... 

Carbonylation Reactions (105,163). Reppe (160) allowed acetylene, carbon monoxide, and tetracarbonylnickel to react in the presence of acids... 

Derivation (1) Condensation of ethylene oxide with hydrocyanic acid followed by reaction with sulfuric acid at 320F (2) acetylene, carbon monoxide, and water, with nickel catalyst (3) propylene is vapor oxidized to acrolein, which is oxidized to acrylic acid at 300C with molybdenum-vanadium catalyst (4) hydrolysis of acrylonitrile. 

Derivation (1) Ethylene cyanohydrin, ethyl alcohol, and dilute sulfuric acid (2) Oxo reaction of acetylene, carbon monoxide, and ethyl alcohol in the presence of nickel or cobalt catalyst. 

Carboxylic Acids and Esters. The literature on German methods for the preparation of unsaturated acids and their esters via acetylene, carbon monoxide, and water or alcohol, as well as the application of this reaction to olefins, carbon monoxide, and water or alcohol to give saturated acids and esters, is to be found in references (27, 44, 4, 3,94)- Other references on these methods are Blair-McGuffie (7) and Natta... 

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