Alkyl dimers

Liquefied gas fractions (propane, propylene, butanes, butenes) that will be able to provide feedstocks to units of MTBE, ETBE, alkylation, dimerization, polymerization after sweetening and/or selective hydrogenation. 

Thus, perfluoroalkylated imidazoles are obtained in excellent to good yields (Scheme 3.7) [16, 17]. Similarly, a hindered phenolate anion provides a fluoro-alkylated dimeric product in high yield (Scheme 3.8) [173. 

The vinyltin 45 also can be used as an unsaturated system for C-H transformation of nitriles Id and le producing the corresponding alkylative dimerization products of the vinyl group, 1,4-disubstituted butene derivatives 46 (Scheme 10) [14]. The reaction proceeds in a stereoselective fashion to give the trans isomer selectively. Malono-nitrile does not react with the vinyltin under the reaction conditions. 

The term Kolbe electrolysis is sometimes exclusively used to denote the formation of alkyl dimers R-R, path a) in Eq. (94) (see Sect. 12.1), while the reaction leading to substituted alkyls, R-Nu, via carbonium ions as intermediates, path b) in Eq. (94), is named non-Kolbe electrolysis, abnormal Kolbe electrolysis,or... 

Fig. 8. Concerted alkylation mechanism including alkylation, self-alkylation dimerization, and hydride transfer via isobutane and via conjunct polymers.

Garst, J. F., Hart, P. W. Evidence against alkyl dimer formation through Sn2 processes in Wurtz reactions of alkyl iodides with sodium in 1,2-dimethoxyethane. Bineopentyl from neopentyl iodide. J. Chem. Soc., Chem. Common. 1975, 215-216. 

In a similar process, addition of triethylaluminum in pentane to 3,3-dimethylcyclopropene in a 1 2 molar ratio gave an alkylated dimer 14 in reasonable yield. 

It should be noted that where the metal alkyl is known to be dimeric, should be substituted for [A], where [A2] is the concentration of metal alkyl dimer and K is the dissociation constant. 

In the absence of other substrates, the corresponding alcohol, aldehyde/ ketone, sulfide (alkyl -I- sulfenyl), and alkyl dimer are isolated [51], The details of all of the studies conducted with this method are beyond the scope of this review, but a brief overview is appropriate. 

The first hydrosilylation reaction catalysed by organolanthanide hydrides was described at the beginning of the nineties (eq. 2) by using metallocene neodymium hydrides as catalysts [25-27]. Nowadays, the more stable and more soluble alkyls dimers with methyl bridges or monomers with CH(SiMe3)2 substituents have been demonstrated to be especially convenient precatalysts and are generally used [28-30]. 

Quantitative data are not available for the majority of these systems, but several studies have appeared that deal with the relative stabilities of the simple alkyl dimers (48-50) and of a few olefinic derivatives (W). Some of the pertinent data are collected in Table I. These data clearly establish that increasing the chain length decreases the stability of the dimer shifting the equilibrium to the right. Further chain branching causes a similar effect. 

The Ciba-Geigy group have reported further work on their promising amide-linked systems. A -Alkylated dimers of type 212 [Tttr = tris(p-r-butyl)trityl] have been prepared, and incorporated into oligonucleotides, to probe hydrophobic effects in duplexes with RNA complements. The same team has also prepared building blocks of types 213 - 216 (B=Thy or 5-Me-Cyt) and investigated the effects of the methoxy/hydroxy substituents on hybridization with RNA sequences, and types 214 and 216 increased Tm by 2-3 °C per replacement. In this work, a route was developed to the branched-chain unit 217, in which an... 

Amines, coco alkyl, ethoxylated, N-oxides. See PEG-3 cocamine oxide Amines, N-coco alkyltrimethylenedi-. See Cocopropylenediamine Amines, N-coco alkyltrimethylenedi-, acetates Amines, coco alkyltrimethylenedi-, diacetates. See Cocodiamine acetate Amines, C18-unsaturated alkyl, dimers CAS 68201-29-6... 

See Amines, C18-unsaturated alkyl, dimers Kemamine N-650. See Cocopropylenediamine Kemamine N-970. See Hydrogenated tallow 1,3-propylene diamine Kemamine N-974D. See Tallow nitrile Kemamine P-650 Kemamine P-650D. See Cocamine... 

Alkenyl succinic anhydride Allyl urea Aluminum nitrate Aluminum nitrate nonahydrate Amines, C18-unsaturated alkyl, dimers... 

Silicone emulsion Wollastonite extender, polishes Calcium monocarbonate extender, polishing powders Calcium sulfate dihydrate extender, polyamide resins Tosylamide/formaldehyde resin extender, polymeric systems Amines, C18-unsaturated alkyl, dimers extender, printing inks Coumarone/indene resin Kaolin extender, PU... 

Amines, C18-unsaturated alkyl, dimers Kemamine DP-3680 Kemamine DP-3695 68201-46-7 Cetiol HE Estol E03GC 3606 Extan-PGC Glycerox HE Hetoxide GC-30 Hetoxide GC-80 Mazol 159 Milopol G-7... 

As an example, this apply to enols or tautomeric enols such as maleic acid derivatives. While with a chemical reagent (cerium ammonium nitrate) the only process occurring is oxidative dimerization, when aromatic nitriles are used as the photochemical oxidant, selective trapping of the radicals by an electrophilic alkenes or by the nitrile itself occurs. Under these conditions, both the alkylation of alkenes and the oxidative alkylation/dimerization of dienes have been smoothly obtained (see Scheme 8) and side processes such as double alkylation or polymerization often occurring with other methods have been avoided. A three-component (Nucleophile-Olefin Combination, Aromatic Substitution) process is also possible. ... 

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