bers. T h e f i r s t s u c h c o m m e r c i a l process of catalytic cracking is the Houdry process in which the heavy hydrocarbon vapors are passed through a fixed bed of the catalyst, beds being alternately regenerated by blowing with air. Although Houdry is himself French-born, the process has been developed in this country. I t is being used extensively at the present time. More recently new processes of catalytic cracking have been developed which make the operation entirely continuous. The fluid catalyst process suspends the finely divided solid catalyst in the vapor stream and later separates it, regenerates it, and returns it. The Thermofor catalytic process uses a catalyst bed which moves downward through a tower, the catalyst
being continuously removed from the bottom for regeneration. Although no substantial commercial experience on
these processes is yet available, extensive commercial installations are beiiirf made. The gasoline from all of the catalytic processes may be retreated with catalysi, resulting in virtual elimination of the olefins and increase in the aromatics. For many years cracking, by one method or another, has been used on a comparatively small scale to make certain special products other than gasoline, as, for example, ethylene or aromatics. Recently the dem a n d for i s o b u t a n e , butènes, and butadiene has focused attention on these other materials. The wide cracking knowledge and e x p e r i e n c e possessed by technical men in this country are making the solution of these problems immeasurably easier.
Nitroparaffins Η . Β. Η ASS, Purdue University, Lafayette, Ind. T ^ H B first nitroparaffin was reported in 1872 by Meyer and Stiiber who reacted amyl iodide with silver nitrite. Eight years later Beilstein and Kurbatov treated a heptane fraction with nitric acid in liquid phase and obtained a mixture of isomeric nitroheptanes. In the half cen tury between 1880 and 1930 numerous investigations were carried out in Russia,
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Germany, and the United States to dis cover a method of utilizing this reaction for the commercial production of nitro paraffins, but in spite of approximately six thousand literature references on the aliphatic nitro compounds, none had reached commercial production. In 1930 work was started at Purdue on the assumption that isobutane, the
21-NOVEMBER
10,
1942
nitration of which had not been reported, might, because of its unique structure— nine relatively unreactive primary hydro gen atoms and one easily sμbstituted tertiary hydrogen—make it possible to obtain better yields of mononitroparafnn than had resulted from the other alkanes. Reaction was slow until the critical tem perature of isobutanc had been exceeded.
1369
New and Rare Instruments H P H E Committee on Location of New and Rare Instruments has the following offers and requests: Instruments Offered Curie electrometer (Paris make) Loewe-Zeiss liauid interferometer L. & N. portable potentiometer (No. 7655) with 2 quinhyarone and I calomel elec trodes Microammeter, D'Arsonval Type (model S of Sensitive Research Instrument Corp). Rental only Quartz microscope Siemens & Halske optical pyrometer Two-circle reflecting goniometer (several) We^h d. c. volt-ammeter (0-150 volt, U-15 ampere) Westinghouse 4-unit moving coil Type PA oscillograph with three galvanometers Weston galvanometer (No. 375) Weston galvanometer (No. 440) Weston voltmeter (No. 280) Instruments N e e d e d Coleman spectrophotometer (10 requests) Gratine spectrograph (9 requests) Leitz Ultrapak or equivalent Quartz spectrograph Zeiss Optimeter Zciss-Pulfrich refractometer (8 requests) Then it was rapid, and the expected prod uct, tertiary nitrobutane, was obtained in fair yield. Other alkanes, however, reacted similarly under these conditions. The advantages of the flow method in studying vapor-phase reactions had been apparent for some time in our chlorination researches and this technique was then applied to the nitration. Shorter exposure times and lower pressures in the flow method, as compared with operations in bombs, required higher temperatures for reasonably rapid reaction. Under these conditions an entirely new nitration re action occurred with a fission of carboncarbon linkages. R R ' + N 2 0« — > · RNOa + R'NO, Thus isobutane yields, in addition to the tertiary nitro derivative, l-nitro-2-methylbutane, 2-nitropropane, and nitromethane. Soon after preliminary work had in dicated the advantages of the new tech nique in nitrating paraffins, a prominent manufacturer of natural gas gasoline sponsored a fellowship with the Purdue Research Foundation to study the proc ess and the properties and uses of the nitroparaffins. After definitely encourag ing laboratory results had been obtained, this company decided not to go into the manufacture of chemicals and discontinued support of the research. The Commercial Solvents Corp. and one of the important explosive companies thereupon displayed an interest in the nitroparaffins, but after a careful study of nibglycerol trinitrate, OaNCCCHjONOs)*, and nibglycol dinitrate, CH 8 C(NOuKCHaONOa)*, they decided not to engage in such manufacture. Commercial Solvents, however, soon erected a pilot 1370
plant for the nitration of propane, butane, and isobutane so that quantities of nitro paraffins could be manufactured for re search on applications and for market exploration. The courage and vision displayed by Commercial Solvents Corp. in embarking upon a wholly new technique and in opening up a field of chemistry in which there was no previous record of commercial success can hardly be overestimated. Costly delays were inevitable as problems arose and had to be solved. The pioneer ing nature of the development was well expressed by the Patent Office which stated, in response t o a second patent application from the Purdue Research Foundation, that its original patent (U. S. 1,967,667) "represents the complete state of the art so far as known". The first pilot plant was destroyed byfire. The second one, however, operated even more successfully than the laboratory experiments had promised. I t is still in 24-hour daily operation because the large plant is unable to meet the market demand for nitroparaffins. Commercial operation began in May 1940 after a few birth pangs characteristic of a radically new process. The only major disappointment of the entire development is the disparity be tween the size of the present unit and the demand for nitroparaffins and their de rivatives. At present the process is operating with propane as the starting material and yields nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, five nitroalcohols and nitroglycols o b tained by formaldehyde condensations with these nitroparamns, the five corre sponding reduction products, the aminohydroxy compounds, and salts of hydroxylamine. Potential sales are at least 10 times the present plant capacity. CHEMICAL
If you have rare instruments you would be willing to sell, lend, or lease for essential war research or if you need such instru ments, write to D. H. Killeffer, 60 East 42nd St., New York, Ν. Υ., chairman of the committee, who has particulars on the offers and requests mentioned above.
Data Published on Selective Service " D B C A U S E of the wide interest in " ^ t h i s subject and the need for obtaining trained men for our Pro duction Army, we give below refer ences to information we have pub lished on occupational deferments, including those of men in training, and the need for technically trained persons. Future developments will be brought to the attention of our readers. Chemical and Engineering News ( N E W S EDITION previous to
1942)
Vol. IS (1940), pages 890, 1127 Vol. 19 (1941), pages 129, 311, 457, 459, 489. 520, 587, 681, 797, 1164, 1412, 1464 Vol. 20 (1942), pages 110, 157, 472, 579-80, 788, 812, 837-39, 985, 1099,1100,1219, 1294 Current issue, page 1392 Industrial and Engineering Chemistry Vol. 33 (1941), pages 1, 135, 283, 561 Vol. 34 (1942), pages 2, 131, 259, 648, 1134
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