Alkylammonium salt alkene

Arco have developed an integrated process for the production of industrially important epoxides via an adapted AO process (Figure 1.13).33 34 A sulfonic acid substituted alkylhydroanthraquinone alkylammonium salt is reacted with molecular oxygen to form the alkylanthraquinone and hydrogen peroxide. The hydrogen peroxide is then reacted with an alkene in the presence of a titanium zeolite catalyst (TS-1 see Chapter 4). The epoxide product is then separated, and the anthraquinone salt recycled to a hydrogenator for reaction with... 

Alkenes may be obtained by elimination reactions from alkyl haUdes, alcohols, sulfonates or amines. The substitution pattern of the alkene and the stereospecificity of these methods depend quite subtly on the structure of the individual substrate. If the leaving group occupies an unsymmetrical position in a compound, one of two isomeric alkenes can be formed (Scheme 3.1). Elimination to give an alkene bearing the greatest number of alkyl groups is known as the Saytzeff elimination and is commonly found with alkyl halides. When the elimination gives preferentially the less-substituted alkene, it is known as the Hofmann elimination This substitution pattern is commonly foimd with the elimination of alkylammonium salts. In practice, mixtures of alkenes are often obtained. 

T etra-w-alkylammonium salts ofPCoWu0395-, CoW12O406- Alkenes Epoxides... 

Method using Base and a Substituted Halogenomethane. The influence of catalyst anions (as their tetrabutylammonium salts) and cations (as chlorides or bromides) on the generation of dichlorocarbene from chloroform-sodium hydroxide has been studied under standard conditions by determining the yield of dichloronorcarane produced from the addition of the carbene to cyclohexene. The presence of olefin appears to be necessary since in its absence only very slow decomposition of the trichloromethyl anion occurs. Dehmlow has also devised a new procedure for phase-transfer-catalysed cyclopropanation. Treatment of an alkene (or cycloalkene) with sodium trichloroacetate and a tetra-alkylammonium salt in chloroform without... 

Quaternary alkylammonium salts, tertiary amines, and crown ethers have all been utilized as catalysts in the reaction of hydroxide with chloroform to yield dichlorocarbene. The most commonly utilized catalyst has been benzyltriethylammonium chloride (see Sect. 1.7) but other quaternary ammonium chloride catalysts have proved effective. Cetyltrimethylammonium chloride and tricaprylmethylammonium chloride (Aliquat 336) have both been used effectively in the cyclopropanation of simple alkenes. The use of Z e a-hydroxyethyltrialkylammonium hydroxides as phase transfer catalysts results in increased regioselectivity in the addition of dichlorocarbene to olefins [12]. Crown ethers such as dibenzo and dicyclohexyl-18-crown-6 have both been utilized in place of quaternary ammonium compounds. 18-Crown-6 has also been used as a catalyst in the phase transfer thermal decomposition of sodium trichloroacetate to yield dichlorocarbene [13]. 

For the oxidation with potassium permanganate in water it is necessary to use a phase-transfer catalyst to obtain high yields.34 35 The phase-transfer agents are generally quaternary Letra-alkylammonium or phosphonium salts in concentrations of about 0.5-5 mol % relative to the alkene. Using this method several carboxylic acids, such as tetrafluoro-3-iodopropanoic acid,34 perfluoroheptanoic acid.35 perfluoroundecanoic acid,35 perfluorononanoic acid,35 and pcrfluorooctanedioic acid35 can be prepared. In a similar way, 3-(perfluoro-1,1-dimethyl-butyl)prop-l-ene can be oxidized.36... 

One of the most important transformations catalysed by palladium is the Heck reaction. Oxidative addition of palladium(O) into an unsaturated halide (or tri-flate), followed by reaction with an alkene, leads to overall substitution of a vinylic (or allylic) hydrogen atom with the unsaturated group. For example, formation of cinnamic acid derivatives from aromatic halides and acrylic acid or acrylate esters is possible (1.209). Unsaturated iodides react faster than the corresponding bromides and do not require a phosphine ligand. With an aryl bromide, the ligand tri-o-tolylphosphine is effective (1.210). The addition of a metal halide or tetra-alkylammonium halide can promote the Heck reaction. Acceleration of the coupling can also be achieved in the presence of silver(I) or thallium(I) salts, or by using electron-rich phosphines such as tri-tert-butylphosphine. ... 

In a manner similar to platinum ones, rhodium—carbene complexes have been recently tested in the hydrosilylation of alkenes and alkynes (3). Especially, rhodium complexes with N-heterocyclic carbene (NHC) ligands have attracted considerable attention. Their performance is comparable with that of phosphine complexes. The following exemplary ligands were used 1,3-imidazoylidene chelate bis(imidazolinum-carbene) phosphine-functionalized NHC alkylammonium-imidazolium chloride salts NHC pincer complexes, pyridine-functionalized N-heterocyclic carbenes (also with iridium), and bis(dichloroimidazolylidene) (also with iridium). 

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