An Inexpensive Pyrex Photochemical Reactor
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Numerolls photochemical reactions can be bnntght. about by irradiation wit,h visible light,. In srtch cases, Pyrex phot,ochemical reactors are preferred because of their low cost and hecause they effectively fiker wavelenglhs shorter than 300 nm which mav brine about, secondarv olrotochemieal reactions. The numose of t,his article is t,o describe a n innxnennive Pvrex nhoto" chemical react,or for which I fonud extensive use while working a t Haile Selassie I University ill Addis Abrtha, Ethiopia t,his past year. The react,or is constmcted, with only slight madificat,ion, from an ol.diuxry dtying pistol' and theappropria1.e sire'ground glass cap from a gas wa3h bottle. The figure shows the reador in cross section. The t,wo side arms of the outer chamber, A, of the pivtol are fitted by means of one-hole rubber stoppers wibh water inlet,, B, and ont,let, C tubes. For more efficient cireulnt,ion, the inlet tube is bent downwards snd ext,ended by mems of x short length of a.
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Tygon tubing, D. The inside chamber, E, of the pistol will hold 00 ml of reactiou solntion and is best stirred magnetically. The solution can be purged of oxygen before and during phot,olysir by passing an inert gasVhrough the solotion via t,he gas dispersion tubeF, fused to thegas inlet tube, G, of the wash bottle cap. I n t,his laboratory, two Phillips 150-W spot lamps placed a t a 45" angle to each other and 10 cm from (he reactor are used as the light source. Cooling to below room temperature is accomplished by passing a rapid stream of tap water thraueh the outer iacket of the oistol. When occasion demands. an aonronriate filter solr~tionis circulated thn,trgh rhr m t r r jacket by m m m of :t riwdnriug pttmp.' 11) th.; rs+, I . o u I ~ ~ L .:.t n w m ~ p l i 4 1 Ity d ~nmqitlgI I ~ ~ ~ u I I I ha111. twn rhrough a 1-m l r ~ g t huf spirnlrrl cbppcr rul,ing whwh i i ~ t b m r r g r dIII :,I. ~re-~:tlt
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' Available from Arthur H. Thomas Co. with 340/35 ground inuer joiut a t the entrance.
Caps from tall form gas washing bottles with $ ground outer joints available from Arthur suitable. 2
568
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Journol of
Chemicd Education
N. Thomas Co. nrc
