Methanol radical

In the middle range of styrene concentrations, a compromise is attained where there is sufficient styrene to scavenge all excess methanol radicals not involved in activation of the trunk polymer, yet an excess of monomer remains for grafting by the charge-transfer mechanism proposed by Dilli and Garnett (12) originally for copolymerisation to cellulose (4) and subsequently extended to wool (3), polyolefin (2,5) and PVC (13) systems. The data in Table V are consistent with this interpretation. 

The initial transient formed, rearranges in a reaction that involves the ring contraction step in reaction (74). The lifetime of this intermediate is considerably longer than that reported for any other intermediate with a copper(II)-carbon bond in aqueous solution (85-87,101,136), suggesting the stabilized structure featuring the metallocycle. This intermediate decomposes via heterolysis of one of the copper(II)-carbon -bonds followed by homolysis of the second to form the cyclopentyl-methanol radical in reactions (75) and (76), which reacts with Cu + to form the final product cyclopentanecarbaldehyde (89). 

The large negative potential of the methanol radical (-0.95 V vs. NHE) [86] induces electron injection into colloidal Ti02 at 120 K with formation of surface trapped electrons and formaldehyde. Consequently, the yield of electrons is doubled (Fig. 1.10). This spectrum... 

Cationic radicals are much less stable and noticed prominently in mass spectroscopy. When a molecule in gas phase is subjected to electron ionization, one electron is abstracted by the electron beam to create a radical cation. This species represents the molecular ion or parent ion, which on fragmentation gives a complex mixture of ions and uncharged radical species. For example, the methanol radical cation fragments into a methyl cation CFl and a hydroxyl radical. Secondary species are also generated by proton gain (M -F 1) and proton loss (M — 1). 

This oxidation of the methanol radical, originally postulated by Hughes and Willis (30) is almost diffusion controlled. 

In strongly alkaline solution, where the methanol radical is ionized [pK CH2OH = 10.6 (13)], the reaction is somewhat slower. 

Figure 2 shows the test of this equation in the competition of oxygen and ferricyanide for the methanol radical in neutral solution. The plot is linear, as required and from the slope the rate constant ratio, kyt/ks, and hence the absolute rate constant for the oxygen reaction, can be obtained directly. Table V list someexamples of reactions of this type. 

Calculated geometry of methanol radical cation. (Adapted from reference 295.)... 

Two new synthetic methods for the preparation of functional polymers containing 2-oxazoline pendant groups were developed. The first concerns the synthesis of m- and p-vinylbenzyl ethers of 2-(p-hydroxyphenyl)-2-oxazoline, followed by their radical poljnnerization. 2-(p-Hydroxyphenyl)-2-oxazo-line was reacted with a mixture of m- and p-chloromethylstyrene (60% m and 40% p) under phase transfer catalysis conditions at room temperature. The m-and p-vinylbenzyl ethers of 2-(p-hydroxyphenyl)-2-oxazoline obtained were separated by selective crystallization from methanol. Radical polymerization of these ethers was carried out in dioxane at 60 C, giving polymers with pendant 2-oxazoline groups. 

The hemithio orthoester 169 was prepared from lactone 168 by treatment with Lawesson s reagent, then reaction with methyl iodide and methanol. Radical desulfurization of 169 gives predominantly a 2Hdeoxy-P-glycoside 170 by transfer of hydrogen to an intermediate methoxy-substituted anomeric radical preferentially from below (Scheme 40). P-Selectivity is, however, enhanced when an alkoxy substituent is present at C-2 [114],... 

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