Improved Dropping Funnel. John Mitchell, Jr., and J. W. Hcndemon, Ammonia Department, E. I. du Pant de Nemoucs & Company, Inc., Wilmington, Del. N a pievious publication from this laboratory [Lupton, .J.
1Mitchell,
M.,
J., Jr., Oemler, A. ti., and Woolover, L. B., J . Am. Oil Chern. Soe., 25, 216-18 (194231, a msnudly controlled dropping funnel (Dropolator) was described for use in the ashing of lard. More reeenily a similar dropping funnel w&s reported [Human, J. P. E., and Mills, J. A,, ANAL.CHEIX., 21, 428 (1940) I The Dropolator sample holder has been modified to permit better control in a wider number of applications. I n addition to its use in delivering molten materials, the new unit can he employed for t,he controlled discharge of many solids. The transfer is essentially quantitative-for example, gravimetric checks during deliveries of 100-gram quantities of ethylene glycol and adipic acid indicated a holdup of less than 0.1 gram of sample. The principal improvement involves the use of a timercontrolled feed rod instead of the manually operated drop control rod described in the earlier publication. In the nea sample holder the rod (see figure) is enlarged a t the lower end and mound to make a firm gravit,? seal with the ground seat. A magnotic won oluneer i s sealed into the ippe; end of the rod. About a 2-mm. clearance isleft
;ombination hn- and off-cycle repeat timer. (A suitable timer i s manufactured by the C. C. Wilson Company, Chatham, N. J., and may be obtained from Eck Rr Krebs, 131 West 24th St., Kew Yark, N. Y.) Positioning of the solenold far optimum lifting of the control rod requires oareful adjustment. This is done conveniently by c l , p p ing the solenoid to a rack and pinion mount. The spherical joint, held with a spring clamp, permits ready dismantling of the sample holder for cleaning purposes, ctc., and the larger sidearm grind is more convenient for introducing solid materials. Both heating jacket and crucible holder are the same as those described previously, and the procedure is unchanged.
In addition to its use for lard, the versatility of this apparatus has been demonstrated by controlled deliveries of other liquids and severel solids. Adipic acid was handled either as liquid or as solid. In the former case, the Nichrome ribhon-wound heating jacket was adjusted to maintain the adipic acid just above its melting point. In the latter, the dried solid, preferably in the particle sise range of 20- to 60-mesh, was added a t room temperature. There was no tendency toward caking when the solid was essentially dry. Comparative duplicate analyses of an adipic acid gave ash values of 13 * 0.0 p.p.m. by the Dropolator method (delivered either as liquid or solid) and 16 + 3 p.p.m. by the common dry-ashing procedure.
374
Othor compounds which have been handled successfully include methanol, ethyl aloohol, nonyl alcohol, adiponitrile, isobutyl acetate, ethylene glycol, propylenc glycol, linseed ail, and thiodipropionic acid 8 6 liauids: and thiodmrmionie acid and sodium earhonate as
Reduced Pressure. J. Allen Brent, Jr., and J. Erskine Hawkins, University of Florida, Gainesville, Fla. HE removal of small samples of distillate for analysis when T o p e r a t i n g under reduced pressure is usually a somewhat tedious procedure. To simplify this operation a combination sample thief and receiver of simple design was constructed.
is n 14/35 standard-taper capillary tubing stopcock shell, A . Two hales about 0.5 mm. in diameter are drilled in the joint to align with the holes in the stopcock shell. The joint i s then converted into the hollow plug, R , by senling it at the bottom about. I cm. below the holes and adding a handle. Another hole about 0.5 mm. in diameter is then drilled close to the bottom of the plug a t an angle of 90" from t,he first hales. When the uppcr hales are aligned with the stopcock shell holes, the bottom hole is against the side of the shell. I n this position liquid Hows into the hallow plug and fills it to its capacity of approximately 0.3 ml. Additional liquid washes through and out the opposite side, where it Hows into the graduated receiver, C. Because of it,s small capacity and the continuous replacement of distillate in the plug, the composition of the sample is that of the last few dram of distillate collected, far each volume indicated in the The main featurc of this
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