Tertiary toluene metalation

Imidazolium salts that can be prepared by the first procedure, the alkylation of imidazole, are easy to obtain and often used for metal complex synthesis. Potassium imidazolide is reacted with the first equivalent of alkyl halide in toluene to give the 1-alkylimidazole. Subsequent alkylation in 3-position is achieved by addition of another equivalent of alkyl halide [Eq. (2)]. " A variant of this approach employs commercially available A-trimethylsilyl imidazole with 2 equiv of an alkyl chloride, under elimination of volatile MesSiCl. The drawback of these simple routes is the fact that only primary alkyl halides can be reacted in satisfactory yields because secondary and tertiary alkyl halides give substantial amounts of elimination by-products. 

Tertiary amines such as N,N,N, N, -tetramethylethylenedia-mine (TMEDA) and l,4-diazabicyclo[2.2.2]octane strongly catalyze metallations by alkyllithium reagents. Uncatalyzed lithiation of toluene is very poor5 whereas by contrast, a yield of 90% has been obtained when TMEDA is employed as a catalyst. ... 

Another approach for the preparation of dendrimer-noble metal nanoparticles in toluene is a process driven by acid-base chemistry and ion pairing [35]. At first, palladium nanoparticles are prepared by reducing aqueous K2PdCl4 with sodium borohydride in the presence of G4 dendrimer where the pH of dendrimer solution is adjusted to about 2. The low pH protonates the exterior amines to a greater extent than the less basic interior tertiary amines. Accordingly, Pd2+ binds preferentially to the interior tertiary amines and upon reduction palladium particles form within the dendrimer interior. After the complete reduction, the pH of solutions is adjusted back to about 8.5. Then, these nanocomposites can be quantitatively transported from the aqueous phase into toluene containing 10-20% of dodecanoic acid. The transition is visualized by the color change brown aqueous solution of dendrimer-palladium nanoparticles becomes clear after addition of the acid, while the toluene layer turns brown. 

The idea that transition-metal complexes can act as PT agents was presented in some early studies of metal-complex-catalyzed reactions under PTC conditions. Lately, several approaches to the design of bifunctional catalysts have been made. Organometallic complexes capable of effecting phase transfer reactions were prepared for the first time in 1982 [192, 193]. Tertiary phosphines containing polyether substituents react with Pd(PhCN)2Cl2 to afford complexes capable of catalyzing the reduction of bromobenzene with NaH suspended in toluene. 

On Pt/AljOj catalysts, 1,2-dimethylcyclopentane produces both toluene and n-heptane. The amounts of both products increase with decreasing hydrogen pressure 94) (see Section IV, Table VI). However, under the same conditions, toluene is not formed from 1,3-dimethylcyclopentane or from ethylcyclopentane. This suggests that metallocyclobutanes are more easily formed (or cleaved in the appropriate fashion) when a tertiary carbon atom is involved in the bonding with the metal. 

Thorium is one of the few multivalent metals [others are Au(III), Ce(IV), U(VI), and Cr(VI)] which are extractable as nitrate complexes from nitric acid solutions [25-28]. The extractants used include TBP in CCI4 [26,29], TOPO in cyclohexane, toluene or xylene [25,30,31], and triphenylarsine oxide in CHCI3 [27]. Other reagents used for extraction of the nitrate complex of thorium include dibutyl dithiophosphate in various organic solvents [32], dibutyl sulphoxide in xylene [28], and bis(2-butoxyethyl) ether [33].The liquid anion-exchanger Aliquat 336 in xylene [34] and a solution of tertiary ammonium salt (Hyamine) in dichloroethane [35] have been also proposed for extraction of Th. The presence of Li, Na, or A1 nitrate improves the extraction of thorium. Sulphate, phosphate, and tartrate do not interfere, but fluoride must be masked, e.g., by aluminium. Thorium has been separated from U and Pu with the use of Alamine 336 and TOPO (in xylene or cyclohexane) [36]. 

Both types of reaction are carried out in apolar organic solvents, such as benzene, toluene or chlorinated hydrocarbons. For the enhancement of the reaction of isocyanates with hydroxy compounds, metal salts or tertiary amines are used as catalyst. In the case of reaction (h) the hydrochloric acid liberated is bound with a tertiary amine (pyridine, triethylamine). 

In some cases, the hydrocarbon oxidation in the presence of a reductant does not need a transition metal complex as catalyst. Thus, a cathode of a carbon whisker has been found to be active for the oxidation of toluene into benzaldehyde and benzyl alcohol during the H2-O2 fuel cell reaction [58a]. During the electrolysis of water at room temperature, the epoxidation of hex-1-ene and hydroxylation of benzene to phenol and hydroquinone occurs simultaneously on the anode and the cathode, respectively [58b]. Finally, selective oxidation of terminal isopropyl groups to the corresponding tertiary alcohols have been carried out by an electrochemical method [58c], Using the... 

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