Sodium alkyl group exchange

A statistical exchange of alkyl groups occurs with sodium tetraalkylaluminates ... 

Figure 5.41 Relationship of PaN0< to carbon number of alkyl groups of a poly (N-n-alky 1-4-vinylpyridinium bromide) layer formed on a membrane surface. AEM anion exchange membrane without a layer CH with a layer of poly(N-n-octyl-4-vinylpyridinium) bromide C with a layer of poly(N-n-dodecyl-4-vinylpyr-idinium) bromide Ct6 with a layer of poly(N-n-hexadecyl-4-vinylpyridinium) bromide. A 0.25 N sodium nitrate and 0.25 N sodium chloride mixed solution was electrodialyzed at 10 mA tcm 2 for 60 min at 25.0 °C, with the polysoap layer on the membrane surface facing the desalting side.

The main feature of the reactivity of alkylpyridines is deprotonation of the alkyl group at the carbon adjacent to the ring. Measurements of side-chain-exchange in methanolic sodium methoxide, 4 2 3, 1800 130 1, and of pK values in tetrahydrofuran each have the 7-isomer more acidic than the a-isomer, both being much more acidic than the / -isomer, though the actual carbanion produced in competitive situations can depend on both the counterion and the solvent. Alkyllithiums selectively deprotonate an a-methyl where amide bases produce the... 

The main feature of the reactivity of alkylpyridines is deprotonation of the alkyl group at the carbon adjacent to the ring. Measurements of side-chain-exchange in methanolic sodium methoxide, 4 2 3, 1800 130 and of pK values... 

Heating peralkylated derivatives 56a in BBr3 leads selectively to the 6-bromo derivatives 56b via Br/alkyl exchange [74], Among other transformations, the reaction of 56b with the sodium salt of a thioazadiiron cluster is an example of combining main group and transition metal clusters in one molecule (56c), which provided crystals for structural characterization (Scheme 3.2-29) [75]. 

The dichalcogenides of group VI do not readily form intercalates with organic molecules. But n-alkylammonium compounds can be prepared by ion-exchange reactions of the hydrated sodium intercalation compounds such as Na j(H20)o g M0S2. Alkylammonium compounds prepared by this route show lattice expansions that depend on the alkyl chain length, very similar to the MX2-n-alkylamine systems described above. This raises the fundamental question whether protonated amines are the actual intercalated species in both the cases, involving reduction of the host. In fact, this constitutes the basis of the new model for the intercalation reaction in MX2 proposed by Schollhorn (1980). 

Kreiter (67) first demonstrated by XH NMR spectroscopic studies the acidity of hydrogen atoms that are bonded at the a-C atom of alkoxy-(alkyl) carbene complexes. In CH3OD solution, in the presence of catalytic amounts of sodium methanolate, pen tacarbonyl[methoxy (methyl) car-bene cliromiumfO) exchanges for deuterium all hydrogen atoms of the methyl group that is situated next to the carbene carbon ... 

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