Benzophenone ketyl

Benzene is distilled over benzophenone ketyl and stored under a nitrogen atmosphere. 

Ethyl ether is freshly distilled from sodium/benzophenone ketyl at atmospheric pressure under nitrogen. 

Rapid purification Check for peroxides (see Chapter 1 and Chapter 2 for test under ethers). Pre-dry with CaCl2 or better over Na wire. Then reflux the pre-dried solvent over Na (1 % w/v) and benzophenone (0.2% w/v) under an inert atmosphere until the blue colour of the benzophenone ketyl radical anion persists. Distil, and store over 4A molecular sieves in the dark. 

Toluene (99.9%) is purchased from Fisher and dried by distillation under argon from sodium benzophenone ketyl. 

The submitters used THF that was freshly distilled over Na/K alloy NMP was distilled over CaH2. The checkers used commercially available anhydrous THF and NMP obtained from Aldrich Chemical Co. There appears to be a slight increase in yield when THF distilled from sodium/benzophenone ketyl is used instead of the commercial THF. All other solvents used were of reagent grade quality and were used without further purification. 

Tetramethydisiloxane was purchased from Lancaster Synthesis Inc. and used as received. THF was obtained from Mallinckrodt Inc. and freshly distilled from sodium/benzophenone ketyl. 

Tetrahydrofuran (THF) was distilled from sodium/benzophenone ketyl under a nitrogen atmosphere. 

Dioxane was heated at reflux with sodium overnight under nitrogen, benzophenone was added, and the solvent was distilled after appearance of the deep blue color of the benzophenone ketyl. 

The checkers dried and purified the dioxane by distillation from the sodium-benzophenone ketyl. 

Sodium benzophenone ketyl Benzophenone, radical ion (1 —), sodium (8) Methanone, diphenyl-, radical ion (1-), sodium (9) (3463-17-0)... 

Most polymerizations were carried out in tetrahydrofuran (THF) (Fisher, Certified Grade) which had been previously distilled from the purple sodium/benzophenone ketyl. 

If the primary chemical process is still abstraction of a hydrogen atom to produce the benzophenone ketyl radical, one would expect to observe some mixed pinacol product arising from coupling of the benzophenone ketyl and acetone ketyl radicals,... 

As seen earlier in this section, the energy released upon formation of the benzophenone ketyl radical is about 104 kcal/mole. This value is almost identical to that released upon formation of f-butyl alcohol from the f-butoxy radical,... 

S)-Ethyl lactate, [other chemicals employed in this procedure were obtained from Aldrich Chemical Company, Inc. Anhydrous tetrahydrofuran was prepared by distillation under argon from sodium benzophenone ketyl. 

Tetrahydrofuran is distilled from sodium-benzophenone ketyl under argon. The reaction may be carried out using a freshly opened can of anhydrous diethyl ether from Fisher Scientific or Mallinckrodt without further purification. 

Ether was distilled from benzophenone ketyl under nitrogen before use. 

Tetrahydrofuran is freshly distilled from sodium benzophenone ketyl. 

Ether was distilled from benzophenone ketyl under nitrogen. The checkers used ether dried over 4 A molecular sieves, under nitrogen, for 2 days and obtained the same results. 

THF is distilled from benzophenone ketyl and stored over sodium wire under a nitrogen atmosphere. For the drying procedure and caution, see Org. Synth., Coll. Vol. VI11990, 451 and Org. Synth., Coll. Vot. V1973, 976 respectively. 

The ESR detection of benzophenone-ketyl radical coupled with the formation of pinacols as byproducts (in Scheme 9) provides the basis for an electron-transfer mechanism between carbonyl acceptors and various Grignard reagents48 (equation 23). 

Fig. 11 Transient spectra obtained upon the application of a 200-fs laser pulse to a solution of [Ph2C(0H)C02, MV2+] charge-transfer salt showing the simultaneous formation of benzophenone ketyl radical (dashed line) and the reduced methyl viologen (dotted line). The inset is the authentic spectrum of ketyl radical. Reproduced with permission from Ref. 92a.

The tetrahydrofuran was dried by distilling from lithium aluminium hydride and then from sodium benzophenone ketyl (generated by adding small pieces of sodium metal and benzophenone) directly into the reaction flask. A blue-black color of the ketyl solution indicates dryness. The checkers purified tetrahydrofuran by distillation from sodium hydride dispersion under nitrogen, and used it immediately. 

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