Hydrocarbons acid halide synthesis

James Mason Grafts discover that an aluminum chloride catalyst transforms organic chlorides into hydrocarbons and acid halides into ketones. This becomes known as the Friedel-Crafts reaction and is important in chemical synthesis. French physicist Louis-Paul Cailletet and Swiss physicist Raoul Pictet liquefy ojQ gen. 

Organometallics are generally strong nucleophiles and bases. They react with weak acids, e.g. water, alcohol, carboxylic acid and amine, to become protonated and yield hydrocarbons. Thus, small amounts of water or moisture can destroy organometallic compounds. For example, ethylmag-nesium bromide or ethyllithium reacts with water to form ethane. This is a convenient way to reduce an alkyl halide to an alkane via Grignard and organolithium synthesis. 

The only formic acid derivative that allows the direct formylation of aromatics is formyl fluoride1617 since others (halides and the anhydride) that could be used in Friedel-Crafts-type acylations are quite unstable. Other related methods, however, are available to transform aromatic hydrocarbons to the corresponding aldehydes. The most frequently used such formylations are the Gattermann-Koch reaction16 17 and the Gattermann synthesis.10 16 17... 

The most favorable conditions for obtaining molecular complexes of o-hydroxyazomethines of type 856 are created by use of strong Lewis acids, for example halides of metals of Groups III-V of the Periodic Table, and aprotic organic solvents with a low dielectric constant (hydrocarbons and their halogen-substituted derivatives). An example of such synthesis is the preparation of complexes of salicylideneimines with titanium and tin tetrachlorides (4.25) [101] ... 

Synthesis of pure enantiomers. Brown and Singaram1 have reviewed the chiral organoboranes obtained from (+)- and (- )-pinene and their use for synthesis of optically pure amines, halides, hydrocarbons, lithium alkylborohydrides, ketones, aldehydes, a-chiral acids, esters, nitriles, alkynes, and alkenes. 

Halides are second only to carboxylic acids in their versatility in organic synthesis. Functional group transformations into alkenes, alkynes, amines, aldehydes, alcohols, ethers, hydrocarbons, ketones and other groups may be performed with ease in high yield. However, the major synthetic importance of halides arises from the ease by which compounds that contain this functionality may be used in carbon-carbon bond-forming reactions and in the preparation of heterocyclic compounds. 

Anhydrides—Continued reduction to alcohols, 155 reduction to lactones, 535 Arenes, see Hydrocarbons, aromatic Amdt-Eistert reaction, 433, 487, 573 Aryl esters. Fries rearrangement, 344 hydrolysis, 169 preparation, 169 Aryl halides, see Halides Atyloxy acids, preparation, by aceto-acetic ester synthesis, 430 by malonic ester synthesis, 429 from atyloxy alcohols, 419 from atyloxy cyanides, 414 preparations listed in table 48, 460 Aryloxy acyl halides, preparation, 547 preparations listed in table 61, 553 Aryloxy esters, preparations listed in table 55, 516... 

Williamson s S3mthesis.—This reaction is known as Williamson s synthesis because, in 1851, he showed, by it, the true constitution of ether, and made possible the explanation of its preparation from alcohol and sulphuric acid as given a little later on. The reaction is similar to the Wurtz reaction between sodium and an alkyl halide by which a hydrocarbon is formed. 

Deoxygenation. Alkanes are obtained from alcohols by reaction with PdClj-EtjSiH (by adding an alkyl halide such as Mel to the reaction medium the halides are produced). Secondary allylic alcohols and acetates are reduced to the hydrocarbons with EtjSiH-LiClO. The facile removal of the oxygen atom from aryl ketones by TiCl -mediated reaction with Et,SiH makes the synthesis of a-amino acids containing carbon chains of different length and a terminal aryl group much easier. A synthesis of CHIRAPHOS via the phosphine oxides calls for deoxygenation with HSiCl -EtaN." ... 

A MW-assisted protocol for the synthesis of azides, thiocyanates, and sulfones has been developed (Scheme 12) that has proved to be a useful alternative, as the use of environmentally deterimental volatile chlorinated hydrocarbons is avoided.All the reactions with these readily available halides or tosylates have shown significant increase in reactivity, thus reducing the reaction times with substantial improvement in the yields. Various functional groups such as ester, carboxylic acid, carbonyl, and hydroxyl were unaffected under the mild reaction conditions employed. This method involves simple experimental procedures and product isolation which avoids the use of phase-transfer catalysts, and is expected to contribute to the development of greener strategy for the preparation of various azides, thiocyanates, sulfones, and other useful compounds. 

Aromatic hydrocarbons and aryl halides can be converted into sulfinic acids in yields averaging 80% if the reaction is carried out at low temperature, if, as in the Gattermann aldehyde synthesis, reaction is initiated by passing in dry hydrogen chloride, and if the tetrachloroaluminum sulfinate formed is decomposed, not by acid, but by alkali, and acid is used for the first time to decompose the alkali sulfinites thus formed.240 Aryl ethers give sulfinic acids even in the cold, but reaction readily proceeds further to give sulfoxides and sulfonium compounds 241... 

Preparation of Alkyl Halides from Olefins. There are two general methods for the synthesis of alkyl halides (1) by the interaction of an alcohol with a halogen hydride—a procedure that may reasonably be discussed under esterification or halogenation and, also, under the Friedel-Crafts synthesis when a metal halide is used to catalyze the reactions— and (2) by the addition of a halogen hydride to an unsaturated hydrocarbon. This reaction may be catalyzed by metal halides and by sulfuric acid. In the latter instance, the ethylsulfuric acid first formed is converted to the halide by gaseous chlorine or chlorine liberated in situ by action of sulfuric acid on a halide. 

Fittig discovered diphenyl. He applied Wurtz s reaction (see p. 509) to the synthesis of aromatic hydrocarbons by the action of sodium on a mixture of an aryl and alkyl halide. Fittig synthesised mesitylene, showed that it is symmetrical trimethyl benzene, and investigated its oxidation, so discovering m-xylene and isophthalic acid. With J. H. Eaton he first prepared the complex salts K4Mn(CN)e and K3Mn(CN)6 in the solid form. ... 

An alternative method for the preparation of carboxylic acids is the reaction of nitriles with sulfuric acid. This reaction is important in organic synthesis because it can be used to extend the hydrocarbon chain by one carbon atom. Nitriles can be obtained from the corresponding alkyl halides in the reaction with HCN by nucleophilic substitution. Nitrile can easily be oxidized to carboxylic acid. 

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