Glass Pressure Vessel with Heatihg Jacket. John H. Pomeroy, Division of Biological and Medical Research, Argonne National Laboratory, Chicago, 111. GLASS
and stainless steel pressure vessel for use at pressures
A up to 4 atmospheres and temperatures up to 150’ is described. It is simple to build and use and its glass construction enables the to observe the of the reaction with convenience and safety. It has been used for catalytic hydrogenation when mounted on a variablespeed shaker, and Arnold [Arnold, J., Scia c e , 114, 178 (1951)] has used it to improve penetration of eelloid in embedding solutions into bones for histological sectioning, The frame of the a p p a r a t u s was made of a 5 X 19 inch piece of 0.25inch c o l d - r o l l e d steel, into which had been milled two parallel slots, 0.25 inch wide and 0.125 inch deep, 0.125 inch from the long edges. This piece, when c u t and welded together as shown in Figure 1, f o r m e d the top, bottom, and side. Into the slots were fitted two 5 X 9 inch pieces of 0.25-inch safety glass as front and back windows. In the top plate was cut a hole, 2.625 inches in diameter i n t o which t h e standard Corning flangefits. The0.5 inch hole in the bottom plates is of use if the reaction vessel becomes stuck. The heating element, G, uses about 130 watts a t 110 volts. The curve of maximum temperature us. voltage applied by a variable t r a n s f o r m e r is a s t r a i g h t line between 40 volts (80 ”) a n d 120 volts (280”). The Nichrome wire was wound on 0.5-inch a s b e s t o s tape, as recommended by Glasebrook and W i l l i a m s (Glasebrook, A. L., W i l l i a m s , F. E., “ T e c h n i q u e of Organic C h e m i s try,” Vol. IV, p. 246, New York, Int e r s c i e n c e Publishers, 1951), and was secured a t each end by fastening to a small cleat made
A
D
from glass rod, as shown. The reaction vessel comes to working temperature rapidly, usually within half an hour. To obtain a better fit of the jacket tubing, F , each piece was selected for roundness and cut to a right cylinder. The Transite blocks N , were turned by the machinist to fit the individual portions of tubing, as some in size were found. A circular gasket of asbestos cord was placed in the bottom of the outer circular groove, to act as a cushion for the tubing. The reaction vessel, M , was made of a portion of borosilicate glass pipe, 1.5 inches inside diameter, finished with a test tube seal, and thoroughly annealed. The Corning Glass Works reconlmends 50 pounds per square inch as maximum pressure t o be used; in this diameter tubing this actually includes a large safety factor, and Pressures of 60 pounds per square inch have been used without incident. Snecial heat-treated elass which is renorted to withstand much higher pressures is &ailable from the Corning Glass Works. For convenience in handling small amounts of material, such as may be found in tracer s ntheses, a centrifuge tube in a stainless steel carrier may be usegas an insert or liner. The apparatus was attached by means of rubber pressure tubing to the valve, tank, and gage assembly from a Parr pressure reaction apparatus (Model 3911, Parr Instrument Co., Inc., Moline, Ill.); other similar arrangements may be used. It is recommended that Type 347 stainless steel be used in the cover, 6,and piping, particularly if halogen-containing materials are to be used. Hydrochloric acid solutions will attack the thermometer stem a t higher temperatures, unless i t is protected by a well made of glass tubing.
If the reaction vessel is to be used for hydrogenation, care should be taken in selecting the kind of pipe “dope” used in assembling the pipe fittings, as some kinds contain catalyst poisons. Glyptal varnish has been used satisfactorily. The recommendations of James Kotora, Jr., of the Division Shop, in the design and construction of this apparatus are gratefully acknowledged. Apparatus for Observing Emulsions. W.C. Griffin and R. W. Behrens, Atlas Powder Co., Wilmington, Del. examination or comparison of emulsions involves measurement of separation or creaming. The extent of such separation is often obscured because of the opacity of the layers when the samples are viewed with either diffused or reflected light. Transmitted light properly utilized permits observation and measurement with satisfactory precision. The types of containers most used in emulsion studies are heavy glass sample jars and graduated cylinders; both tend to obscure separation. Heavy glass walls cause excessive internal reflection of light. The graduation lines on cylinders cause stray reflections. Containers of large diameter make it difficult to obtain a light source of sufficient intensity to permit the observer t o see through HE
Figure 1. Glass Pressure Vessel with Heating Jacket
plate
D. 6/16-18 screws with wing nuts:
3 required 120’ apart on 3 8 / 8 inch diameter bolt circle: screws welded to frame E. 1/8 inch gasket (rubber, neoprene, Koroseal, or Te0on) F . Borosilicate glass tubing, 60-mm. and 73-mm. diameter, each 71/r inches long G. Heating element, 25 turns of No. 30 gage Nichrome wire; requires 16 feet H . No. 20 gage stainless steel cover plate, perforated with I/a-inch holes on 8/16 inch staggered centers I. 1/c inch diameter X 8 inch long machine screws: 4 required J. 1/z X 1/n inch No. 20 gage stainless steel angle, spot-welded to cover plate k’. No. 5-40 screws to fasten cover plate; 4 required L. Standard Corning flange for 11/z inch I.D. glass pipe, Corning Glass Works, Corning N . Y . .M. 11/2 inch ’I.D. borosilicate glass pipe, Sl/a inches long S. I/z x 41/4 x 47/8 inch Transite, 2 reuired. anchor t o base with 26/6-18 I l l e n Lead cap screws (not shown) 0. No. 18 gage parallel lamp cord, length as P. Silver-soldered required joint, copper to Nichrome
Figure 1. Apparatus
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