Methane alkylation

Halogenated methanes Alkyl-N- nitrosamines Carbamates Aliphatic epoxides... 

In on attempt to generate primary (trivalent) cations and to simulate the ethylene-methane alkylation, ethyl chloride was reacted with methane (eq. 3) under alkylation reaction conditions (28). When no propane or propylene product was observed, the energetically more favorable reaction of methyl chloride with ethane was carried out (eq. 3a). These two reactions proceeded without any involvement of the alkane and provide evidence that the ethylene-methane alkylation proceeds through a more stabilized species such as a pentacoordinoted carbonium ion. The behavior of these alkyl chlorides will be discussed separately after the alkylation chemistry. 

Tris(pyrazolyl)methanes alkylated on the methyne carbon atom have been synthesized.255,256 Methylation of (HC(pz)3) was carried out according to Scheme 20. The synthesis of alkylated tris(pyrazolyl)methanes was only successful when the pyrazole rings contained no alkyl substituents on the 5-position (Scheme 20). 

These stages result in the formation of the active form of the catalyst. The next is the key stage of ethylene insertion at the methane-alkyl bond, whose multiple repetition results in the polymeric chain growth. The reaction ceases when the metal in the catalytic complex is reduced to the trivalent state. 

Me3CCH2CMe2C H40H. M.p. 8l-83"C, b.p. 286-288°C. Made by alkylation of phenol. Forms oil-soluble resins with methanal (salts used as oil additives) and surfactants (with ethylene oxide). 

Silyl ethers serve as preeursors of nucleophiles and liberate a nucleophilic alkoxide by desilylation with a chloride anion generated from CCI4 under the reaction conditions described before[124]. Rapid intramolecular stereoselective reaction of an alcohol with a vinyloxirane has been observed in dichloro-methane when an alkoxide is generated by desilylation of the silyl ether 340 with TBAF. The cis- and tru/u-pyranopyran systems 341 and 342 can be prepared selectively from the trans- and c/.y-epoxides 340, respectively. The reaction is applicable to the preparation of 1,2-diol systems[209]. The method is useful for the enantioselective synthesis of the AB ring fragment of gambier-toxin[210]. Similarly, tributyltin alkoxides as nucleophiles are used for the preparation of allyl alkyl ethers[211]. 

An alkyl group lacks one of the hydrogens of an alkane A methyl group (CH3 —) is an alkyl group derived from methane (CH4) Unbranched alkyl groups m which the point of attachment is at the end of the chain are named m lUPAC nomenclature by replac mg the ane endings of Table 2 2 by yl... 

Chlorination of methane and halogenation of alkanes generally proceed by way of free radical intermediates Alkyl radicals are neutral and have an unpaired electron on carbon... 

The elimination of alcohol from P-alkoxypropionates can also be carried out by passing the alkyl P-alkoxypropionate at 200—400°C over metal phosphates, sihcates, metal oxide catalysts (99), or base-treated zeoHtes (98). In addition to the route via oxidative carbonylation of ethylene, alkyl P-alkoxypropionates can be prepared by reaction of dialkoxy methane and ketene (100). 

ALKYLATION OF ALIPHATIC COMPOUNDS The first reported alkylation of branched-chain alkanes by ethylene, over aluminum chloride (69), made it possible to alkylate alkanes (except methane and ethane) with straight chain or branched alkenes. 

Carbanioas derived from the other above mentioned methane derivatives react with alkylboranes, bornic, and boronic esters, providing rich possibihties for the preparation of siagle-carbon iasertion products. Thus 2-aLkyl-l,3,2-dithiaborolanes are converted iato acids or thioacetals by trichloromethyllithium (335). 

Scandium triflate and lanthanide triflates also catalyze alkylation by secondary methane-sulfonates. ... 

The groups at the termini of the 1,4-pentadiene system also affect the efficiency and direction of the the di-7c-methane reaction. The general trend is that cyclization oceurs at the diene terminus that best stabilizes radical character. Thus, a terminus substituted with aryl groups will cyclize in preference to an unsubstituted or alkyl-substituted terminus ... 

The catalyst must also be selective to valuable products. Gasoline is desirable, so a lot must be produced, but it must be high octane gasoline. Cj s and C s are sometimes required for polymerization, alkylation and chemical production. Certain catalysts give high yields of these compounds, especially the imsaturated components. Gases, such as methane and hydrogen, are undesirable so the yield of these products must be suppressed. 

Chlorine gas reacts directly and highly exothermically with alkanes, giving rise to alkyl chlorides and hydrogen chloride, e.g., for addition to methane. 

Treatment of the sodium salt of carbostyril with chlorodifluoro-methane and sodium <-butoxide in 1,2-dimethoxyethane gave the products of 0- (49) and iV -alkylation (50). ... 

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