May, 1919
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 C H E M I S T R Y
The distillation is carried on until the boiling point of the distillate is 100’; this will insure all the alcohol being removed. The flask is then emptied of what remains, including the bulk of the platinum black t h a t has been reduced. Then the flask is refilled and the operation repeated until all the washings have been treated. A t the end the flask is washed free of all the platinum black. A t this point the platinum has all been reduced and can be washed and treated further in its recovery as in the method where zinc and hydrochloric acid are employed. The next procedure is the removing of the aldehyde from the alcohol, which is easily accomplished by means of fractional distillation. The flask is set up as in the first operation except t h a t this time i t is connected directly with a n Allihn condenser, serving the purpose of a reflux condenser. As the aldehyde boils a t about 2 I O and the alcohol a t 7 8 O , their separation is easily effected. Warm water should run through the Allihn condenser and should be so regulated t h a t This is hot a t the outlet the temperature is 58’. enough t o allow the aldehyde t o escape and a t the same time condense the alcohol provided the boiling is not too vigorous. At the top of the Allihn condenser is a delivery tube t h a t leads t o the coil condenser used in the first operation. This can be used t o condense the aldehyde and what small amount of alcohol is liberated. The distillation is carried on until the distillate from the coil condenser shows no trace of aldehyde. A simple and delicate test is made by mixing a few crystals of phenol with 5 cc. of concentrated sulfuric acid in a test tube. Three cubic centimeters of the distillate from the outlet of the condenser are caught in a test tube, one cubic centimeter of the acid mixture added and the whole shaken. If there is a trace of aldehyde a reddish brown solution will result; if not, a colorless solution will persist. The operation is continued until the alcohol is freed of all the aldehyde. Then the alcohol is removed, the flask refilled with the alcohol containing the aldehyde, and the operation repeated until all the alcohol has been freed from the aldehyde. When the distilling is completed, if the volume of the distillate of t h e aldehyde mixture is sufficient, i t can be re-distilled t o recover alcohol liberated with the aldehyde. Then a few pieces of sodium hydroxide are added t o the distilling flask which can be connected directly with the coil condenser and the alcohol is distilled until the sp. gr. 0.8645 is obtained. This is the specific gravity of the alcohol used in the washing of the potassium chloroplatinate as given by the official methods. The first impression may be t h a t the operation is lengthy and requires considerable attention, but in actual use i t is quite the opposite. I n fact, it can be handled along with the regular laboratory work and inconvenience one very little. Last year the author recovered 40 liters of alcohol in this manner in connection with the platinum recovery and the process required only little attention. Where a large number of potash determinations have t o be made, necessi-
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tating in the course of time the consumption of large quantities of alcohol, i t is well worth considerable effort t o recover the alcohol. CHEMICAL LABORATORY DOLDPACKING COMPANY
JACOB
WVICHITA, K A N S A 5
A SlMPLIFIED SIGNAL DEVICE FOR THERMOMETRIC READINGS-COAL CALORIMETERS B y H. s. V A S 5 A R Received February 20, 1919
I n a recent number of THISJ O U R N A L ’ appeared a description by Chas. A. Myers, Jr., of a timing device used in the chemical laboratory of the New York Navy Yard for giving “warning” and “reading” signals when making calorimeter determinations.
FIG. I
I n applying this equipment to a smaller laboratory where but two calorimeters are in operation certain changes have been made simplifying the equipment and giving very satisfactory results. The apparatus used (Fig. I ) consists of one zo-ohm relay, one single stroke bell, 3 dry cells, and the same “timer” 20 O b as t h a t used by Mr. I Relay Myers, connected as shown in the accompanying sketch. Aside from the simple wiring the only labor required Flexible Leads was t h a t of placing the contacts on the clock and wiring them t o the 3 binding posts on the clock case. Instead of cementing platinum foil contacts t o the clock face, con1/2 minute switch tact pieces cut from German silver are fastCut Off switch ened in place with small machine screws FIQ.2-TIME SIGNAL DEVICEFOR C O A L CALORI~SETER and nuts. I n installing this equipment the switches for starting and for cutting the half-minute signal “in” or “out” were mounted on the edge of the calorimeter table convenient t o the operator; the relay, bell, and
/I
1 1 0 (1918), 101.5.
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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
Vol.
11,
No. 5
battery were placed on the under side of the table, and the clock with its flexible leads a t any convenient point. This leaves t h e calorimeter table clear. The single signal for both “warning” and “reading” has been found perfectly satisfactory. Attention is called t o these modifications t o enable small laboratories t o receive the benefits of Mr. Myers’ equipment with somewhat less labor in the construction of the device. TESTING LABORATORY PUBLIC SERVICE ELECTRIC COMPANY NEWJERSEY NEWARK,
A DEVICE FOR REMOVING PLUGS FROM STOPCOCKS’ By VERNONC. ALLISON Received February 1 7 , 1919
It is very annoying t o have a stopcock stuck on a piece of calibrated apparatus, or, in these days of high prices, on any piece of apparatus. This frequently happens in burettes, separatory funnels, glass set-up systems, and apparatus used in gas analysis work, due t o the use of caustic, bichromate, and many other solutions, The common method of removing the stuck plug is t o place a small piece of wood on the plug and t o more or less gently hammer the wood, resulting in a great many cases in the barrel being cracked, the plug chipped, and, in complex apparatus, breakage of important parts. If, however, a steady pressure is exerted on the plug with the glass in contact with nothing but wood, the plug can easily be removed without damaging either barrel or plug.
FIG, %--METHOD
O F OPERATING
STOPCOCK STEM REMOVER
About 2 0 stopcocks have been removed with this, device with no casualties, and in one instance, 7 stuck stopcocks on burettes were successfully removed i n 4 min. CHEMICAL RESEARCH LABORATORY STATXON PITTSBURGH EXPERIMENT BUREAUOF MINES,PXTTSBURGH
DATA ON PLATlNUM GAUZE USED AS A CATALYZER FOR THE OXIDATION OF AMMONIA. TABLE OF WEIGHTS AND ACTIVE SURFACE OF PLATINUM, AIR SPACE, ETC., SHOWN FOR A UNIT OF ONE SQUARE INCH OF GAUZE OF A GIVEN MESH AND DIAMETER OF WIRE By ALVINALLENCAMPBELL Received December 14, 1918
The tables listed below are figuied on t h e basis of one square inch of gauze as a unit. TABLEI-ACTIVS
SURSACS OF
Mesh 80 80 100
120 150 150
74 S/DE EL PVAT/ON
SECTION THRU RA
FIG. I-STOPCOCK STEMREMOVER
The two accompanying figures show a device which has been used very successfully a t the Pittsburgh station of the Bureau of Mines. Fig. I shows the device designed t o operate over almost any size stopcock in common use and is constructed of hard maple or lignum vitae, making it very strong and durable. Fig. 2 illustrates the method of applying t h e steady pressure with a vise in case of loose apparatus. If the stuck stopcock is located on a set-up piece of apparatus, a U-clamp can be substituted for t h e vise. 1
Published by permission oE the Director of the Bureau of Mines.
PLATINUM IN ONE SQUARE INCHOF G A U Z ~ Diam. Wire Pt Surface Inch sq. In. 0.0026 0.0030 0.0026 0.0020 0.0015 0.0020
1.3873 1 ,5841 1.6951 1.4748 1.4821 1.9573
The first section shows t h e mesh or number of wires from center t o center each way per linear inch. The mesh should be accurate and can only be made so when woven on an automatic loom. TABLE11-WEIGHT Mesh 80 80 100
120 150 150
INCH Diam. Wire Inch
PER SQUARE
0,0026 0.0030 0.0026 0.0020 0.0015 0.0020
OF
G A U ZIN ~ GRAMS Wt. per Sq. In. Gram 0.33815 0.46592 0.42268 0.29863 0.2 1009 0.37329
Under t h e heading “Diameter of Wire” a factor of error, either plus or minus, must be taken into consideration for the reason t h a t it would be practically impossible t o draw any considerable amount of extra fine wire t o a given size with a working tolerance of
