March, 1923
INDUSTRIAL A N D EhTGINEERIATG CHEJIISTRY
fatty acid and the mixture shaken with a dilute solution of sodium silicate, we find that the suspension of lampblack so produced is characterized by unusual stability. This same stability does not result if sodium silicate is added to a suspension of lampblack previously produced by mixing it with a neutral hydrocarbon oil and shaking with a pure soap solution. In connection with the reaction of sodium silicate and free fatty acid, mention may be made of the soap-sparing effect which results from the action of the silicate as a neutralizing reagent for stronger acids which decompose soap with formation of free fatty acid or acid soap.
TABLEVI-DROP Per cent Soap 0.25 0.20 0.15 0.10 0.05 0.00
, 0.00 56 44 34 26 18 13.5
243
NUMBERS FOR SOAP SOLUTIOXS WITH ADDED SODIUM
SILICATE
Per cent Sodium Silicate-0.05 0.10 0.15 62 48 .. 39 .. 47 31 .. 36 23 27 14 ii 14
..
;:
7
0.20
.. .. .. ..
i3.5
0.25 91 76 59
45 33 13.5
drawing the air which displaced the kerosene in the dropping pipet through a gradually decreasing head of water in a closed vessel. These drop numbers show less increase due to sodium silicate than was observed by Elledge and Isherwood for the EFFECTOF SODIUM SILICATEUPON THE EMULSIFYING POWER case of sodium carbonate, whether comparison is made on equal-weight or equivalent-weight basis. Direct comparison OF TRUESOAP of two observers is, however, difficult for this method. With Hillyer2 proposed, as a measurement of the relative deter- our own ,apparatus, we obtained a drop number of 50 in an gency of soap solutions, the dekermination of the number of experiment in which 0.10 per cent soap and 0.05 per cent drops delivered by a dropping pipet into kerosene. This sodium carbonate was used, as compared with a drop nummethod has been much used subsequently. Whatever its ber of 60 reported for the same experiment by Elledge and theoretical status, the method appears to afford a practical Isherwood. The drop number which we observed under measurement of the relative emulsifying power of soap solu- like conditions with silicate, instead of carbonate, was 31. tions, and the detergent value must closely parallel the emulAlthough less than in the case of sodium carbonate, the sifying power. increase in the drop numbers of soap solutions against kerSince some kind of alkali is more or less regularly used in osene, produced by sodium silicate is very marked, and laundry work, it becomes of interest to know the effect of indicates a distinct increase in the emulsifying power of the alkali upon the drop qumber of a soap solution as proposed soap solutions. by Hillyer. When added alone to water, alkalies do not ACKNOWLEDGMEKT sensibly affect the drop number of water against kerosene. Hillyer states quite positively that “the number of drops The experiniental work described above was carried out .formed by the (sodium) oleate is not increased by adding by Mr. J. T. R. Andrews and Mr. D. F. Saylor, to whom the excess of alkali to either concentrated or dilute solution of author makes grateful acknowledgment. oleate.” Subsequent investigations throw much doubt upon Hillyer’s observation. Botazzis found that sodium hydroxide, when added to sodium oleate solution, first increased and then decreased the drop number. From the abstracts of this article available Pulp and Paper Industry in Canada to the author it is not clear whether Botazzi’s drop number At the annual meeting of the Canadian Pulp and Paper Associarefers to drop number in air or in some liquid. Incidentally, our own limited observations indicate that sodium silicate tion held in Montreal, January 24 to 26, proposals to include of $30,000 for technical research organization, and $10,000 decreases the drop number and increases the surface tension items for the appointment of a forestry engineer to coordinate methods of soap solutions toward air. and conduct operations to combat the destruction of trees by Shorter and Ellingworth4showed that the drop number of insects and fungi, were referred back to their respective compotassium oleate toward benzene is increased by the presence mittees for another year. $5000 was by resolution put into the budget for the purpose of completing the set of textbooks upon of an excess of alkali. which the industry is basing its educational work. This with Elledge and Isherwoods showed that sodium hydroxide, $21,000 previously raised in Canada and $23,500 in the United sodium carbonate, and trisodium phosphate, all caused States makes a total of nearly $50,000 contributed by the industry marked increases in the drop numbers of solutions of a com- to the work of the Joint Executive on Vocational Education. At the meeting of the Technical Section it was reported that mercial grade of soap of various concentrations toward 230 men from managers down are taking one or another of the kerosene. These same alkalies were found also to increase systematic courses now being carried on. The greater number the amount of lampblack washed through filter paper by soap of these (170) are taking the full course, carried on by corresponsolutions-a fact which affords good evidence of the correla- dence through the specially organized Institute of Industrial and Domestic Arts, with offices at Gardenvale, Quebec, but with tion between drop number and detergent power. a staff comprising experts in each branch of pulp and paperFollowing the method of Elledge and Isherwood, we have making all over the United States and Canada. Sixty more are determined the increase in drop number produced by the studying in classes conducted a t several centers by the University addition of varying amounts of sodium silicate of composi- of Wisconsin. Secretary Beck of the Canadian Pulp and Paper Association reported that the Canadian production of newsprint, tion (Xa2O) (Si02)2.s3 to soap solutions of varying strength in which was 3825 tons daily in 1922, would by the opening of distilled water. The soap was a commercial flake soap con- 1924, with the operation of mills now contracted for, be increased taining 94 per cent true soap. The results are shown in to 4315 tons daily by that time, or 1,300,000 tons per annum. He pointed out that the United States mills had always been Table VI. to produce 58 per cent of the consumption of newsprint on Each of the above drop numbers is the average of two or able this continent and that the contracted mills in Canada would more tests. The dropping pipet had a capacity of 5 CC. by 1924 produce an amount equal to 87 per cent of the consumpThe temperature was maintained a t 100’ C. The time of tion, and added a note of warning as to the approach of the delivery was 2 min., with a variation of * 5 sec. The saturation point. Newsprint production in Canada has increased from 350,000 kerosene level was kept constant and the time controlled by tons in 1913 to over 1,090,000 tons in 1922, or an increase of 2
J. A m . Chem. Soc., 25 (1903),511.
8
Atti accad. Lincei, 21 (1912), 11, 365. Proc. R o y . SOC (London),92A (1916), 231. THISJOURNAL, 8 (1916), 793
4 5
300 per cent in ten years. The pulp and paper exports of Canada were $11,850,632 in 1913, and $163,655,344up to March, 1921. [T. LINDSEY CROSSLEY, Toronto, 0 n t . j
