October, 1925
INDUSTRIAL AND ENGINEERING CHEMISTRY
1023
I n the Burrell process an electric current is caused to flow through an aqueous electrolyte, on the active surface of which is maintained a moving film of an organic liquid to be transformed, the organic liquid being substantially insoluble in, and immiscible with, the electrolvte. As an examde, nitrobenzene is reduced t o aniline, using a cathode having a tin surface and an electrolyte of sulfuric acid.
consists of a plurality of ovens, having combustion chambers arranged longitudinal to the oven walls. Means are provided for supplying gas for ignition purposes to the chambers, the length of the gaseous stream in the chambers being ad-justable.
Rubber Accelerators Several accelerators for use in rubber vulcanization have been patented during the past year. Of interest in this line is the patent to John Young, number 1,538,076, issued May 10, 1925. Young proposes to promote the vulcanization of rubber by incorporating therewith a small amount of a mixture of ditolyl-substituted guanidines including dio-tolylguanidine and di-p-tolylguanidines in which the o-tolylguanidine predominates. Varnish
A catalytic and absorbent material produced from metallic hydroxide gels has been patented by Robert E. Wilson, number 1,540,448, dated June 2, 1925. This catalyst is essentially pyrophoric iron, which is highly porous and infrangible, and in which the pores of the metallic substance are ultra-microscopic. The process of manufacture consists in dehydrating granules of a gel-like, partially hydrated oxide of iron and reducing the metallic substance with hydrogen which has been highly diluted with nitrogen. Some of the uses claimed for this product are the synthesis of ammonia from hydrogen and nitrogen, the oxidation of sulfur dioxide and sulfur trioxide, and the removal or oxidation of sulfur compounds to gases.
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A new phenolic resin varnish of the Bakelite type has been recently patented by Harold C. Cheetham, patent number 1,528,006, dated March 3, 1925. Cheetham calls for a liquid coating composition comprising a phenolic resin of a potentially reactive type together with an organic solvent therefor and furfural. Coal Distillation A patent was recently issued to Elmer J. Crossen, number 1,522,421, dated January 6, 1925, for an improved apparatus for the destructive distillation of coal. This apparatus
Catalyst and Absorbent
Acetone and Butyl Alcohol
A novel process for producing acetone and butyl alcohol has been patented by George W. Freiberg, patent number 1,537,597, dated May 12, 1925. This process is characterized by fermenting carbohydrate material with bacteria which may be widely distributed in nature. The preferred bacteria are anaerobic bacilli with rounded ends, as they form large resistant spores and do not liquefy nutrient gelatin.
Liquid Hydrogen Sulfide as a Source of Laboratory Supply of the Gas' By Charles J. Moore HUNTER COLLEGE
OF THE C I T Y OF
HE notion seems to be prevalent that to liquefy hydrogen sulfide is a risky undertaking on account of the instability of the substance and the possibility of violent thermal dissociation. This, together with the fact that it attacks reducing valves, such as are commonly used on tanks of compressed gases, is probably the reason manufacturers have made no attempt to produce the liquid product until very recently. It is well established that the heat of formation of hydrogen sulfide is positive, and this guarantees that there can be no sudden, extensive thermal dissociation a t ordinary temperature. However, when the writer installed an outfit using the liquid as a source of supply, he was well aware of the possibility of slow, continuous dissociation resulting in excessive pressure due to the hydrogen liberated. I n order to guard against danger, analyses were made of the gas, and even after standing 6 months it was found to contain less than 0.25 per cent of hydrogen. A pressure gage attached to a cylinder for 4 months showed an increased pressure of less than one pound. The pressure in a cylinder containing 20 pounds of the liquid a t 100' F. is 281 pounds per square inch, and a t 150' F. it amounts to 500 pounds. The cylinders are said to have been tested to 3000 pounds. It therefore seems safe to use the liquid. Samples analyzed by the writer seem to be very pure, containing, in addition to the small amount of hydrogen mentioned above, traces of aniline and carbon disulfide from which substances it is produced as a by-product in the manufacture of diphenylthiourea. 1
Received March 27, 1925.
NEWY U R K ,
N E W YORK,
N . 1'.
I n order to avoid the use of reducing valves, a special gasometer has been devised using a seal fluid in which hydrogen sulfide is apparently insoluble. The working of the new outfit has been carefully observed for a period of 6 months, and sufficient data have been collected to justify the following comparisons: The initial cost of the system is more than double the cost of one Parsons generator. To generate 1 pound of hydrogen sulfide, 2.6 pounds of iron sulfide and 6 pounds of hydrochloric acid are required, costing between 60 and 75 cents. The liquid can be purchased in small quantities for 50 cents per pound. The pressure in the gasometer can be regulated a t will and maintained constant. The gasometer can be filled from the highpressure cylinder in a few moments, and an empty cylinder can be replaced in less than 5 minutes. To clean and refill a large generator is a disagreeable task, detrimental to health, and requires considerable time. Generators give little indication that the charge is nearing exhaustion until there is a sudden drop in pressure, which invariably happens when the gas is urgently needed. The disposal of the spent generator liquid is another matter'worthy of consideration, since it is injurious to plumbing and increases to some extent the poisonous component of sewer gases. I n cold weather, especially if sulfuric instead of hydrochloric acid is used, generators become badly clogged with crystalline iron salts, which are often difficult to remove. The writer ventures to predict that the days of the hydrogen sulfide generator are numbered and in a short while will disappear from the chemical laboratory.
