Irradiation apparatus lamps

The irradiations are in general performed under purified, oxygen-free nitrogen in a cylindrical irradiation apparatus with a water-cooled central sleeve into which the lamp is introduced and efficient cooling is used to keep the temperature between 10° and 0° C. Temperatures in the range of 0° to 80° do not influence the photolysis step as demonstrated in the case of a 6j -nitrite, but increase the rate of rearrangement of the nitroso derivative to the oxime. 

Photolysis Reactors and Ultraviolet Sources. For 253.7-m/ irradiation, a modified irradiation apparatus purchased from Delmar Co. was used. The reactor was a 2-necked, 500-ml., round-bottomed flask. One neck was an O-ring joint, and the other was a 24/40 joint. A 4- X 1-inch coiled low pressure mercury quartz lamp was placed inside the flask through the O-ring neck, and the joint was sealed with removable O-rings. The reactor was connected directly to the mass spectrometer by the 24/40 joint. The samples were placed inside the flask and irradiated internally. The O-ring was shielded from direct radiation so as not to induce degradation. The estimated output of the lamp was 30 watts, and the ambient temperature within the reactor during irradiation was 70°C. 

A 1-L Pyrex vessel is charged with 29.5 g (0.13 mol) of (5S)-(5-0-tert-butyldimethylsiloxymethyl)furan-2(5H)-one, 23.7 g (0.13 mol) of benzophenone (Note 10) and 800 mL of methanol. The vessel is placed in a water-cooled, immersion-irradiation apparatus (Note 11), and the solution is degassed for 1 hr in a stream of nitrogen. It is then irradiated using two 125-watt, 350-nm lamps the reaction is complete after 48 hr (Note 12). The solvent is evaporated and the residue is purified by silica chromatography [1 kg of silica, 8.5-cm x 43-cm column with a gradient elution from ethyl acetate petroleum ether (1 1) to neat ethyl acetate]. This yields 18.5 g (55%) of the title compound, 18.3 g (77%) of recovered benzophenone, 3.6 g of benzpinacol,... 

The irradiance of lamps tends to change with time and, if this is monitored, adjustments can be made. UV lamp apparatus can be controlled by replacement and rotation of tubes but an electronic control system has been described76. 

According to ref. 3, nonacarbonyldiiron [Fe2(CO)g] was synthesized by photochemical dimerization of pentacarbonyliron [Fe(CO)s] in a mixture of glacial acetic acid and acetic acid anhydride (10 1) at room temperature employing a Dema irradiation apparatus with a Philips HPK 125 W or TQ 150 W medium pressure mercury lamp. The material should be stored at -25°C in a freezer and handled under an atmosphere of argon. Pentacarbonyliron [Fe(CO)s] was a gift from BASF AG, Germany and was used without further purification. 

Fig. 1. Irradiation apparatus. A, water cooling B, Ar inlet C, septum (rubber) fok withdrawing IR samples L = high-pressure mercury lamp (Philips HPK, 125-W), used in connection with a Philips VGIIHP 125-W power supply converter unit. Dimensions (in mm) a = 400, b = 240, d = 70, e =44, f = 28, g = 6, h = 10, i = 10.

The photo-radical initiator requires a UV irradiation apparatus that can be used in the LCD manufacturing process. Because it is used in combination with metal halide lamps and low wavelength (320-380 nm) cut filters, the absorption... 

Fluorescent ultraviolet lamps within an apparatus that allows condensation cycles rather than the water spray typical of xenon arc tests have been developed for plastics testing (279). The spectral cutoff wavelength of the lamps used in the apparatus determines the severity of the test. Ultraviolet B (UVB) 313 lamps allow a significant irradiance component below 290 nm, which is normally filtered out by the earth s atmosphere. Ultraviolet A (UVA)... 

Although photochemical cycloadditions have gained acceptance in synthetic chemistry, most such reactions are limited to a relatively small scale. The use of a 1000-watt street lamp permits the irradiation of up to 1 mol of substrate in less time than 0.2 mol can be irradiated with the conventional 450-watt lamps. Thus, under optimum conditions, the submitters were able to add ethylene to 3-methylcyclohexenone on a 20-g scale in 48 hr (801) with a 450-watt lamp with the apparatus described here 94 g of this enone was condensed with ethylene in 8 hr (91%). 

Fig. 44 Apparatus for irradiation with UV light. — 1 excitation apparatus (Heraeus, Hanau OSRAM StE 501), 2 UV lamp (TNN 15-31001721), 3 housing, 4 TEC plate.

The imine 13 (1.0-2.0 g) in benzene or CH2C12 (200-300 mL) was irradiated under N2 in an immersion apparatus equipped with a 400-W high-pressure Hg lamp and a Pyrex filter and cooled internally with running water. When TLC showed that all the starting material had been consumed (1 -3 h) the solvent was removed under reduced pressure and the residue was chromatographed (silica gel. CH2C12). 

Our experimental techniques have been described extensively in earlier papers (2, 13). The gamma ray irradiations were carried out in a 50,000-curie source located at the bottom of a pool. The photoionization experiments were carried out by krypton and argon resonance lamps of high purity. The krypton resonance lamp was provided with a CaF2 window which transmits only the 1236 A. (10 e.v.) line while the radiation from the argon resonance lamp passed through a thin ( 0.3 mm.) LiF window. In the latter case, the resonance lines at 1067 and 1048 A. are transmitted. The intensity of 1048-A. line was about 75% of that of the 1067-A. line. The number of ions produced in both the radiolysis and photoionization experiments was determined by measuring the saturation current across two electrodes. In the radiolysis, the outer wall of a cylindrical stainless steel reaction vessel served as a cathode while a centrally located rod was used as anode. The photoionization apparatus was provided with two parallel plate nickel electrodes which were located at equal distances from the window of the resonance lamp. 

The apparatus is dried in an oven at 140° overnight and cooled under nitrogen or argon prior to the irradiation. A Vycor filter sleeve and a 450-watt medium-pressure mercury lamp are placed in the immersion well. The Vycor filter, the quartz immersion well (catlog No. 19434), the 450-watt mercury lamp (catalog No. 679A36), and the requisite transformer are all available from Hanovia Lamp Division, Canrad-Hanovia Inc., 100 Chestnut Street, Newark, New Jersey 07105. 

Figure 3 Scheme of the apparatus for measurement of PCL. 1, Vessel for irradiation of a photosensitizer-containing solution 2, UV lamp 3, shutter 4, injection tube 5, peristaltic pump 6, measuring cell 7, photomultiplier 8, computer. (From Ref. 45.)... 

Irradiation of Sg, dissolved in CS, with the UV radiation of a mercury lamp in a quartz apparatus results in the formation of Sg, S7 and Sjj together with traces of Sg, Sjo and some polymeric insoluble material. After 10 hours the concentrations of Sg and S7 become approximately constant at levels much higher than in liquid sulfur at 160 °C see Fig. Irradiation of either one of Sg, S7 or S g in CS solution also results in mixtures of Sg, Sj and Sg... 

A solution of 18.22 g (0.10 mole) of benzophenone and 11.54 g (0.12 mole) of tetramethylallene in 170 ml of benzene was irradiated with a 450-W mercury lamp in the apparatus shown in Figures 3 and 4. The mixture was purged with nitrogen throughout the irradiation period. After 24 hr the solvent was removed on a rotary evaporator, leaving a yellow oil which showed strong infrared absorption at 10 fi due to the oxetane, and no detectable carbonyl absorption. 

Pcntacarbonyl[(methoxy)(methyl)carbene]chromium(0) (16, R1 = R2 = Me 475 mg, 1.9 mmol) and the chiral ene carbamate (see above equation) (718 mg, 3.8 mmol) in CH2Ci2 (20 mL) were placed in a Fischer Porter pressure tube and saturated with CO (3 eycles to 6.33 atm of CO) and then irradiated (450-W Conrad-Hanovia 7825 medium-pressure lamp, Pyrex well) under 6.33 atm CO overnight. The yellow-green solution was filtered through a pad of Cclitc, and the solvent evaporated. The crude mixture was placed in a sublimation apparatus and heated at 30-50°C (1 Torr) until no further Cr(CO)6 could be obtained. The residue was preabsorbed on silica gel and flash chromatographed yield 319 mg (61 %) mp 133-134"C. 

A suspension of NaHCO, (1.6 g, 19 mmol) and crude 7-diazotrieyclo[3,2.1.12 4]nonan-6-one (70 mg, 0.47 mmol) in dioxane (60 mL) and H20 (15 mL) was irradiated with a medium-pressure Hg lamp in a Pyrex apparatus at 0 nC and the remaining alkaline solution extracted with Et20. The alkaline phase was acidified and extracted with Et20 giving the carboxylic acid as a viscous oil yield 30 mg (45%). 

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