Mercury high pressure

Preparation of 18,20-Cyclo-5a-pregnane-3, 20-diol 3-Acetate ° A solution of 5 g of 3j9-hydroxy-5oc-pregnan-20-one 3-acetate in 1000 ml of spectroscopically pure ethanol is irradiated with a 250 Watt Philips Biosol A mercury high pressure lamp No. 10/27 through a cental water cooled pyrex jacket under nitrogen for 4 hr. The solvent is then evaporated under reduced pressure and the residues from 2 such reactions are combined and chromatographed on 300 g of neutral alumina (activity II). 

Consider now photochemical properties of (=Si-0)3Si-0-0 radicals [56,66,68]. Under the UV irradiation (unfiltered light of a mercury high pressure lamp equipped by a water filter, T — 300 K) the following processes were observed (1) the decrease in the intensity of the EPR signal from peroxy radicals (2) the formation of (=Si-0)3Si-0 radicals whose number... 

Compounds 63 and 64 coexist as a 1 1 equilibrium mixture upon irradiation of one or the other in C6D6 (mercury high-pressure lamp Phillips, HPK 125W, Duran-50 filter). On heating of each of the two isomers separately at 150 °C, compound 65 (yield 100% or 48%, respectively) is formed by a skeletal rearrangement. Finally, compound 67 can undergo complete photochemical isomerization to furnish an isomeric mixture of two compounds 65 and 66 (ratio 80 20) (Scheme 6) <1997AGE1337>. 

Kinetics of the photocatalytic hydrogen evolution was studied in a temperature-controlled 10 ml glass reactor or in a parallel-sided optical glass cuvette. Suspensions were irradiated by the light of mercury high-pressure 1000 W... 

Bis[trifluoromethyl] Ditellurium An apparatus for irradiation consisting of a reaction vessel, a low-temperature (— 25°) cooler with argon adapter, and an external mercury high-pressure lamp (Heraeus, TQ 150) is assembled. Under an atmosphere of argon 2.65 g (10 mmol) bis[trifluoromethyl] tellurium, 13.6 g (200 mmol) furan, and several glass rings are plaeed into the reaction vessel. The mixture is irradiated for 54 h and stirred to remove the tellurium mirror from the walls of the reaction vessel. The solvent is distilled at atmospheric pressure until the bath temperature reaches 80°. The residue is distilled at 0.001 torr by increasing the temperature slowly from — 78° to + 25° yield 43% b.p. 120°/760 torr. 

UV irradiation of a dry benzene soln (120 mL) containing 1,1-diarylethene (0.40-0.05 mol) and diphenyldiazomethane (0.15-0.076 mol) was carried out in an immersion-type irradiation vessel equipped with a mercury high-pressure lamp (Philips, HP 125 W) surrounded by a quartz water jacket. The solution was purged with Oj-free Nj for 15 min prior to the photochemical reaction, which was run under dry Nj. Irradiation, performed at 13 °C, lasted for about 15-30 h. The workup procedure consisted of removal of benzene followed in some cases by column chromatography (50 cm) of the oily product on acidic alumina with various solvents and recrystallization of the colorless crystals from EtOH. 

Figure 1 UV-spectra during irradiation of a tetrazole (compound analogous to 2.7d, see page 142, 1.02 x 10" M in ethanol, mercury high-pressure lamp, pyrex lamp) from H. Meier, H. Heimgartner, Helv. Chim. Acta 1985, 68,1287.

Figure 2 Emission properties of a) mercury low-pressure lamp (strong 254 line), b) mercury high-pressure lamp and c) RPR-3(XX)A lamp for Rayonet photoreactors (3(X) nm line).

Huttner obtained molybdenum complex 215 upon treatment of ligand 115 with butyllithium, followed by BHs THF, tris(acetonitrile)tricarbonylmolybdenum, iodine, and l,4-diazabicyclo[2.2.2]octane (DABCO), in 76% yield as a mixture of two isomers (Scheme 37). Irradiation of 215 with a mercury high-pressure lamp caused ligand exchange with chelation of the remaining phosphane sidearm to give 216 in 72% yield. Oxidation of 215 with O2 under irrradiation resulted in a decarbonylation to give cationic oxomolybdenum complex 217 in 65% yield. 

Photolysis of solid aldrin using a high pressure mercury lamp with a pyrex filter ( i >300 nm) yielded a polymeric substance with small amounts of photoaldrin, dieldrin, hydrochloric acid and carbon dioxide (Gab et al., 1974). When aldrin (166.8 mg) adsorbed on silica gel surface was irradiated by a mercury high pressure lamp ( >230 nm), however, high yields of epoxides were formed. Products identified and their respective conversion yields were dieldrin (63.9%), photoaldrin (5.1%), photodieldrin (2.7%), photoketoaldrin (4.7%), polymer and polar products (23.6%) (Gab et al., 1975). 

Type of lamp Incandescent lamps Tungsten halogen High pressure mercury High pressure sodium... 

FIGURE 3 Dependence of the relative speed of expenditure of the functional groups OCG on the temperature during irradiation in air by polychromatic hght of a mercury high pressure lamp of the films from a mixture of VAVAC and PHB (20%) (1) or from individual VAVAC (2). Points - experimental data, straight-line - calculations by Eq. (2) at the parameter values l,T = 293 K, = 30.4 kJ/mol. 

Polyethylene and polypropylene samples were defatted with acetone and hexane and stirred with a solution of N-(4-azido-2-nitrophenyl)-ll-aminoundecanoic acid (ANPAU) or p-azidobenzoic acid in ethanol. Polymer samples were removed and air dried. After irradiation with a mercury high pressure lamp at 260 run the polymer samples were washed with ethanol. 

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