July, 1917
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
of magnesium salts. Both of these prxciples we have found in our hands t o be efficient. We wish, however, t o present an additional method which is based on a somewhat different principle, and in certain kinds of molybdate residues may be desirable. T h e method consists in t h e precipitation of molybdenum sulfide from a solution slightly acid with nitric acid by means of hydrogen sulfide or t h e formation of a sulfomolybdate solution b y adding hydrogen sulfide t o t h e alkaline solution of t h e “yellow precipitate” a n d subsequently adding hydrochloric acid t o precipitate t h e molybdenum sulfide. Molybdenum sulfide when ignited gives Moo3, which is in condition t o be used again. I n applying t h e method t o waste molybdate liquors which are usually quite strongly acid with nitric acid, t h e solutions should be strongly diluted or t h e excess of free acid should be in large part neutralized with sodium hydroxide, so t h a t t h e limits of acidity should be between 0.1 a n d 0.4 per cent. Hydrogen sulfide gas is t h e n passed through t h e solution. The sulfide settles more rapidly, however, if t h e solution is previously heated. The supernatant liquid can t h e n be siphoned off a n d t h e sulfide washed with water, after which i t can be filtered, dried and roasted. When much iron is present in t h e liquors t h e sulfide should be washed with water containing hydrochloric acid t o remove t h e iron completely. T h e “yellow precipitate” is handled by dissolving in sufficient sodium hydroxide t o make a solution just slightly alkaline t o phenolphthalein. Should t h e precipitate be contaminated b y iron, t h e ferric hydroxide produced b y t h e addition of t h e alkali should be filtered off. T h e filtrate is t h e n diluted a n d hydrogen sulfide conducted through t h e solution t o saturation. Dilute hydrochloric acid is now added until a n excess is present, when molybdenum sulfide separates. The sulfide of molybdenum can be filtered, washed with hot water containing dilute hydrochloric acid, dried and roasted in t h e air t o molybdenum trioxide. CHEXICAL LABOR4TORY UXIVCRSITY O F ~ I S C O \ S I X . MADISOX
NOTE: ORGANIC CHEMICAL REAGENTS FOR SCIENTIFIC AND TECHNICAL LABORATORIES By ROGERADAMS Received June 7, 1917
During t h e last three summers it has been the custom at t h e University of Illinois t o manufacture on a semicommercial scale ( I - t o a-lb. lots) certain organic chemicals; which h a d hitherto not been produced in this country a n d which were necessary for t h e researches in organic chemistry. Each year t h e number manufactured has been increased till at present satisfactory products have been developed for over forty of t h e common organic chemicals used primarily in theoretical organic research, b u t t o some extent in technical laboratories. T h u s it has been possible t o supply t h e Illinois laboratories with many of t h e materials formerly imported from Germany.
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The majority of these substances are not purchasable in t h e open market at t h e present time, so i t was thought it might be a great aid t o other laboratories if t h e y had t h e benefit of t h e experiences a t Illinois a n d t h e opportunity of purchasing such chemicals as might be desired at a price slightly above cost. I n nearly every case t h e substances produced have been compared with Kahlbaum’s products and in every instance t h e products have been found as pure, or purer. Below is given a list of chemicals which have been manufactured, many of which are on hand a t t h e present time. I n continuing t h e manufacture of chemicals this summer, only those chemicals mentioned below, which are out of stock, will be made, unless there may be a n outside demand for others. Processes for at least t e n substances not included in t h e list will be studied also in t h e next few months. Acetamide Acetoacetic ester (ethyl) Acetonitrile
Benzoyl acetone Benzoyl chloride Benzoyl cyanide Benzyl alcohol Benzvl bromide ,Benzyl cyanide Bromoacetyl bromide Bromobenzene Bromonaphthalene (alpha) Dibromo ( 0 ) benzene Dichloracetic acid Dimethyl glyoxime Diphenylmethane
Ethyl benzoate Ethylene bromide Ethyl oxalate r.ivcocoii - ~~~~~~_ Hippuric acid Magnesium (especially prepared for use in the Grignard reagent) Malonic ester (ethyl) Malonic ester (methyl) Mesitylene Methyl oxalate Methylene iodide Nitrobenzoic acid (0) Nitromethane . Oxalyl chloride Phenyl acetic acid Phenyl acetic ester (ethyl) Phenyl alanine Trimethylene bromide Trimethylene chlorhydrin Trimethylene cyanide Trimethylene glycol
If there is a reasonable demand for any particular chemical, which has not been prepared here a n d which cannot be purchased from any commercial concern, t h e laboratories at Illinois will be glad t o undertake such manufacturing a t their expense a n d sell t h e product a t a price slightly above t h e cost calculated from t h e past results. The Division of Organic Chemistry a t t h e University of Illinois has organized itself for this work, t h e preparation being carried out for t h e most part by t h e junior members of t h e staff a n d other graduate students in organic chemistry. These men receive from 2 5 t o 3 j cents per hour for their services. I n this way i t has been possible t o retain many men who might earn much larger salaries outside, b u t who are willing t o s t a y for this particular kind of experience. A number of other laboratories have offered t o assist in this work, if necessary, so as t o aid scientific and technical investigation as much as possible. Prof. P. A. Bond, of Cedar Falls, Iowa. has kindly offered t o prepare sodium nitroprusside for t h e benefit of any who might need this substance. I n addition t o t h e above work, in conjunction with Prof. h l . T. Bogert, information concerning t h e organic chemical reagents purchasable in this country is being collected. Quotations of prices on any of t h e substances above, or any information which i t has been possible t o obtain in regard t o organic chemicals will gladly be given on request. UNIVERSITYOF I L L I N O I S URBANA,ILLINOIS
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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y AN EVAPORATING BATH OF SEA SAND HEATED BY STEAM B Y P. P. I'BTFIRSON
neceivedi-.bruary 24. 1417
The apparatus herewith described has been found so convenient and useful in the laboratories of t h e Department of Soils a t the University of Idaho t h a t i t is thought worth while t o tell other chemists about it. It is made of coils of pipe in a bath of sea sand. The heat is supplied by superheated steam, the flow of which is controlled hy a Sarco steam trap. The t r a y ( A , Fig. I) is made of No. 24 galvanized iron. Of course, it may be a n y size. Ours is z it. square and 4 in. deep. B is a coil of iron pipe well fitted so t h a t i t can carry a pressure of 100 t o 1 5 0 lbs. per s q . in. A t t h e end of this pipe is a Sarco steam trap, C, which allows t h e escape of steain until a certain temperature is reached when i t closes automatically. The coil B is covered with sifted sea sand of about t h e size t h a t will pass a 20-mesh sieve and washed free from small adhering particles. It is found t h a t by t h e use of this bath a much more rapid evaporation can be obtained t h a n with a hot water or steam bath. Aside from this t h e escape of large amounts of steam into t h e room and t h e noise often accompanying t h e same is avoided. T o obtain t h e best results t h e sand should cover t h e coils t o the to z in. so t h a t t h e evaporating dish or depth of I > / ~ casserole may be pressed down into it. When t h e hot sand is allowed t o come u p on t h e side of t h e evaporating dish t h e evaporation is greatly accelerated. A temperature of 140' C. can be obtained in t h e sand be-
bowever, i t has been found t h a t t o avoid this contamination requires no more care than is necessary with t h e old style boiling water bath or t h e s t e a m
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PZO. IILTBS mrir COW ET,(
bath. Thorough washing of t h e sand t o remove all small particles makes t h e avoidance of contamination rather easy. Fig. I1 is a cut of t h e completed bath. Son, P s a r i ~ i r vLABORAIOKY UNIYQXJiIY
0s Ionso,
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AN IMPROVED FORM OF A FUMELESS DIGESTION APPARATUS By
3. S . MCHIROUE
Received Pcbruary 23, 1917
In a recent, investigation involving a relatively large nurnlier of nitrogen determinations, it became necessary, on account of t h e lack of flue facilities, to make use of a Sy Fumeless Nitrogen Digestion Apparatus. During t h e time t h e nitrogen digestions were being made, a number of objectionable features t o this particular apparatus were experienced. The writer has, therefore, enlarged and modified t h e Sy apparatus in such a n advantageous manner as t o consider t h e changes so made worthy of brief notice in t h c chemical Iiteraturc. The chief ooints in which t h e aooaratus shown in t h e accompanying photograph differs from t h e Sy apparatus and the advantages gained therehy a r e a s follows: r--Increased capacity. Since most ready-made nitrogcn distillation apparatus provides for 6 distillations t o be carried on a t the same time, there is a saving ol time by having a n equal number of digestions provided for. *--The lead pipe a n d t h e absorption bottle is a more pcrmanent and satisfactory arrangement for controlling and disposing of t h e acid fumes during digcstion. Practically all t h e fumes are absorbed in t h e bottle mhich can be easily emptied and t h e acid recovered by evaporation, thereby effecting a saving of acid and t h e corrosive action on t h e drain pipes as well. The pump used in drawing t h e fumes into t h e absorption bottle is t h e ordinary type in general use in Iaboratorics. S-Thc shelf E holds 6 beakers which are placed beneath t h e lower end of tlie condensing bulbs, a n d catch tlic acid t h a t drains f r o m t h e condensing tubes after t h e digestion flasks are removed. After t h e digestion is stopped and t h e flasks become cool, a
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I h . I-TOP
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tw-em the pipes. Over t h e hot plaie, whether lieatcd by a gas flame or electricity, this bath has t h e advantage t h a t there is almost no danger at all of spattering. With t h e hot plate it is almost impossible to avoid this trouble. The objection t h a t contamination from t h e sand is likely to take place may be raised and, of course, is t o be taken into account. I n this laboratory,
Vol. 9, No. 7
