REPORT FOR MANAGEMENT
THE BETHlfHEM LAB-LATHE All steel Table w i t h fireproof shelf
VERSATILE LOW IN PRICE Vertical Set-up (additional charge)
s p e c i f i c a t i o n s : Self-centering sleeve grip chuck; length between chucks 36"; total chuck capacity 0" to 14"; radial clearance 8"; motor %2 H.P., A.C. 115 volts. Complete with motor, chucks and variable speed drive.
Ask for Catalog 54 I Ready to use $ 9 6 0 . 0 0
BETHLEHEM Apparatus Company, Inc. HELLERTOWN, PENNSYLVANIA For further information, circle number 14 A-1 on Readers' Service Card, page 51 A
Analysis of Plastics
NALGENE
centrifuge tubes M a d e from the new high density POLYETHYLENE, much publiciz;ed for its high temperature resistance, higher tensile strength, greater rigidity, a n d superior chemical resistance. I t has been tested a t continuous temperatures of 250 °F. compared with 170 °F. for standard polyethylene which means that, now, polyethylene tubes can | H H | TUBES, CENTRIFUGE or TEST Capacity ml Dimensions mm Price ea. be sterilized in a standard autoclave! 75x12 3.5 100 X 13 6.5 100 χ 16 12 115 X 16 13 115 X 19 18 105 X 29 50 162 X 32 100 Conical Type 15 ml capacity Less quantity discounts
.27 .28 .31 .35 .42 .45 .65 .30
At Laboratory Supply Dealers
The
Everywhere
And now, since I wish to draw my examples from first-hand experience, I will turn to the industry with which I am at present connected—the plastics industry. Somehow or other I never feel that the emphasis is the same in this new and rapidly developing industry as in the much older alkali industry. In the latter case one always felt that our real purpose was to try to carry on an old industry with the maximum efficiency. It is true that modern polymers and polymer compositions must be made with maximum efficiency and that in volves a certain measure of shift and day laboratory control. The emphasis I feel, however, is always on change and development. That reflects itself straight away in
NALGE CO., Inc.
R O C H E S T E R 2, Ν E W For further information, circle number 14 A-2 on Readers' Service Card, page 51 A
14 A
nitrate solution. Under conditions of the test, monomethylaniline exerts a slight influence which has to be al lowed for. In the determination of small amounts of monomethylaniline, it is necessary to treat the mixture of amines, in ice cold conditions and in the presence of potas sium bromide, with nitrite and acid producing the iV-nitroso compound from the secondary amine, subse quently extracting this with ether, and evaporating the ether solution under carefully regulated conditions prior to weighing. The most novel and yet simplest method involved the determination of the most important impurity in mono methylaniline—i.e., the dimethylaniline. In order to avoid side reactions, the mixture of amines was treated with acetic anhydride at 0° C. The acetylation product was dissolved in water and the solution diluted to volume. An aliquot of this solution was treated with sodium nitrite and hydrochloric acid and the yellow-colored p-nitrosodimethylaniline hydrochloride subse quently measured in a Spekker absorptiometer using dark blue filters. We were able to make use of that principle of acetylation of the primary and secondary base to determine much larger proportions of dimethylaniline by a rather novel, and, this time, volumetric procedure. The acetylation product of the three amines was dissolved in glacial acetic acid and titrated with perchloric acid in glacial acetic acid media using α-naphtholbenzein as in dicator. Under these conditions only the dimethylaniline titrates. Those methods were speedy and, I believe, trustworthy and, moreover, I have good reason to believe were of value in helping to secure, quite rapidly, supplies of monomethylaniline.
YORK
ANALYTICAL
CHEMISTRY
