October, 1927
INDUSTRIAL A S D EXGINEERISG CHEJfISTRY
Fraction VI gave, after two refractionations, a distillate boiling a t 255-260’ a t 2 mm. (D’). Analysis: 0.1017 gram substance: 0.1004 gram H z 0 and 0.3134 gram COz Calcd. for CzoH300: C 83.85, H 10.55 per cent Found. C 84.04, H 11.06 per cent
All of these analytical samples were tested and each one was found to protect. Acetylation destroyed their antioxidant power. They are all probably the same substance, and form a clear, reddish oil which is, however, not so viscous as the C2,H420acompound isolated from the upper layer fractionation. The wide range of boiling points is no doubt due to overheating the thermometer during the distillation which was conducted over a Wood’s metal bath heated a t 350400° C. They show the same sterol reactions given by the C 2 ~ H 4 2compound. 0S Since it was possible that these substances might be a constant-boiling mixture of alcohols or of alcohols and hydrocarbons, the probability of oleic and linoleic alcohols being present seemed reasonable in view of the presence of octadecyl alcohol.*g These alcohols were therefore prepared and tested, but they showed no antioxidant power; in fact the linoleic alcohol accelerated the oxidation. Such alcohols are therefore very likely not present. No mention of linoleic alcohol in the literature could be found but by employing the Bouveault and Blanc30 method of preparing alcohols from their esters by means of sodium no especial difficulty was encountered in preparing linoleic alcohol from pure linoleic ethyl ester, which was in turn prepared from pure tetrabromolinoleic acid by the method of Rollet.31 The linoleic alcohol thus obtained in 40 per cent yield was a colorless, mobile liquid, b. p. 203’ C. at 7 mm., ny = 1.4615; specific gravity 0.8586 a t 20” C. It readily oxidizes in the air, takes up practically the theoretical amount of bromine to form a crystalline and a liquid bromide, and does not solidify a t 0’ C. 29 Attempts to separate hydrocarbons from unsaponifiable matter by the usual methods (Lewkowitsch, “Oils, Fats, and Waxes,” 5th ed., p. 601) were unsuccessful. 8 0 Compt. rend., 136,1676; 137, 60 (1903). 8 1 Z.physiol. Chem., 62, 411 (1909).
1191
Other Substances Tried
Inasmuch as Whitby had found evidence of magnesium compounds in the liquid f a t t y acid fraction of the resin, the presence of chlorophyll was suspected. When compounded, however, chlorophyll failed to show protective action. Other compounds tried were sitostene, the hydrocarbon derivative of phytosterol, the crude distillation products of rubber, and the crude unsaponifiable material from cottonseed oil, arachic oil, and balata resin, none of which protected. Since radiation of phytosterol and cholesterol with ultraviolet light forms waxy compounds which are so-called “antiisolated ricketic” vitamins, and since the vitamin A, CnH4402 from the high-boiling liquids of the unsaponifiable material of cod-liver oil by Takahashi and his ~ o - w o r k e r sbore ~ ~ some resemblance to our compound, the products of ultra-violet radiation of cholesterol and phytosterol, as well as the ozonides of these sterols and their decomposition products with water, were tested for antioxidant action, but without success. The compound C27H4203 from diacetylpentane, described by Kipping and Perki11,~3was also prepared, but it did not protect. Conclusion
Very little is known about the liquid constituents present in small quantities in the unsaponifiable matter of various plant products. The recent isolation of vitamin E from the unsaponifiable matter of wheat oil by vacuum distillationa4 and the biological significance of these complex substances, which are probably in the nature of enzymes, will no doubt be a stimulating influence in working out better methods for their isolation and may pave the way for their identification.
.
Acknowledgment
The authors wish to express their appreciation to C. M. Carson for valuable preliminary work, and to W. C. Calvert for the preparation of octadecyl and linoleic alcohols. 82 Sci. Papers Inst. Phys. Chem. Research ( T o k 3 o ) ,3, 38 (1925); J . Chem. SOC.( L o n d o n ) , 1926, 3658. Ibid., 67, 26 (1890). Evans and Burr, Proc. Xatl. A c a d . Sci., 11, 334 (1925).
Measurement of the Adhesive Strength of Glue’ By C. E. Lanyon MANNING ABRASIVE COMPANY, TROY,N. Y.
M
ANY methods have been proposed for measuring the adhesive strength of glueJ2 but the results have in general been far from satisfactory. Other investigat o r ~ have ~ , ~ measured the tensile strength of glue. It has often been suggested that the tensile strength of glue is the property upon which the adhesive qualities depend. While for joints of the mechanical type, as in the wood-working industries, this may be true, in the abrasive industry, where we are interested in measuring specific adhesion-i. e., the bond between an abrasive particle and glue-this does not necessarily follow. As a measure of the strength of this bond the breaking strength of briquets made from abrasive and glue solution suggests itself, Received June 13, 1927. For a summary of these methods, see Bogue, “The Chemistry and Technology of Gelatin and Glue,” p. 527. 8 Hopp. THISJOURNAL, 12, 356 (1920). McBain and Hopkins. Second Report of Adhesives Research Committee (British), 1926. 1
Gill6 made briquets of various materials using glue as a binder. He experienced difficulty in drying them and in obtaining consistent results. However, with care in manufacture and by drying in air under natural conditions, this method is capable of giving very satisfactory results. Preliminary Work
A series of tests showed that with 40-mesh sand to obtain even wetting of the grain without having excess glue solution present, about 50 or 60 grams of solution should be added to 400 grams of sand. These quantities will just fill a 3-gang mold. Enough material for each set of three briquets was made up separately and used as quickly as possible in order to keep the mixture fluid and facilitate filling the molds. Force-drying these briquets a t 54’ C. in 20 per cent humidity for 5 days, then seasoning in ordinary air for 2 weeks, gave low and inconsistent results. Examination of the fractured 6
THIS JOURNAL, 7, 102 (1915).
INDUSTRIAL AND ENGINEERING CHEMISTRY
1192
briquet showed that the glue had drained from the center. Subsequent briquets were dried naturally. A study was first made of variables which might affect the strength of the briquet. Unless otherwise stated 400 grams of 40-mesh aluminum oxide and 60 grams of 20 per cent glue solution were used. The glue used had a viscosity of 105 millipoises when tested according to the method of the National Association of Glue Manufacturers. The breaking strength is the average of three breaks. EFFECT OF PAcKIN.a-Identica1 mixtures of abrasive and glue were made up and filled into molds under widely different methods of packing. The results are shown in Table I.
Vol. 19, No. 10 Results
DUPLICABILITY OF TEST BY DIFFERENTOBSERVERSA series of identical briquets was made up, dried, and tested by two independent workers. (Table V) While the individual tests of observer 2 were not so concordant as those of observer 1, the mean of both investigators differs only by about 2 per cent. Table V Observer Number of briquets broken High value, kg. Low value, kg. Average breaking strength, kg. Average deviation from mean, per cent
1 6 319 288 300 o
2 12 333 279 307
8.8
Table I
Run number How packed Breaking strength, kg.
2P
21
Very tightly 329
22
Tightly
Loosely
306
272
Run 21 is the method that was adopted for further work. EFFECTOF LENGTHOF DRYING-A series of similar briquets was allowed to dry, sets of three being broken each week (Table 11).
EFFECT OF PH VALUEOF GLUE'ON STRENGTH OF BRIQUETIn this series the glue solution was brought, by addition of either acid or alkali, to the required p H value, which was determined colorimetrically. The p H of the original glue was 6.1. A maximum briquet strength is indicated a t p H 7.5.6 (Table VI) Table VI
Table I1 Run number Weeks of drying Breaking strength, kg.
23 3 306
24 4 312
25 5 316
26 6 316
All briquets were therefore dried in 6 weeks. EFFECT OF TEMPERATURE OF GLUESOLUTION, SAND,AND hIoLD-The results of a study of these factors are shown in Table 111. Table I11
.
Run number 62 Temperature of sand, O C. 70 Temperature of glue, ' C. 6 0 Temperatureof mold, O C . 27 Breaking strength, kg. 314
63 43 60 27 317
64 27 70 27 312
65 70 70 32 319
66 50 50 50 310
The effect of these variables is very slight. Subsequent tests were made as outlined in run 62. EFFECTOF STORAGEIN DIFFERENT HUMIDITIES-A batch of fifteen briquets was made up as nearly alike as possible, and after partial drying in the laboratory three briquets were stored in each of five different humidities, as shown in Table V. After 4 weeks' storage in these humidities they were broken. Table IV ~~.~~~ 87 88 88 76 58 163
pH of glue
Av. breaking
strength
pH of glue
Av. breaking strength
Kg. 5.1 5.3 5.6 5.8 6.1
Kg.
2 92 287 297 288 311
6.8 7.0 7.5 7.8 8.1
'
312 328 347 327 318
COMPARISON OF VARIOUSGRADESOF HIDE GLUE-A comparison of viscosity (in 12.5 per cent solution a t 60" C.), jelly strength, tensile strength,l and briquet strength of six glues is shown in Table VII. No parallelism between either viscosity and tensile strength or viscosity and briquet strength is evident. Neither is there a parallelism between tensile strength and briquet strength, bearing out the statement made earlier that in joints of the specific type this need not necessarily be so. GLUE
Table VI1 JELLY TENSILE BRIQUET VISCOSITYSTRENGTHSTRENGTH STRENGTH Millipoises Kg./sq. cm. Kg.
~
Run number
Humidity, per cent Breaking strength, kg.
89 58 231
90 37 283
91 17 334
The humidity under which the briquet is stored before breaking is of great importance. It might be expected that a maximum strength would be developed at some intermediate humidity. As this is not the case, it is possible that equilibrium conditions were not established in the time allowed. Experimental Method
From the result of these experiments the following method was devised which gives consistent results: The proportions of abrasive and glue are 400 grams of sand to 60 grams of 20 per cent glue solution. The glue solution is made up by weighing out 20 grams of glue, adding 80 cc. of water, allowing to soak for 2 to 3 hours, and dissolving on water bath to 60" C. The sand is weighed into a clean pan and placed in an oven a t 60" C. for 10 minutes. Meanwhile the mold and plate on which it rests are cleaned and sparingly greased. The pan of sand is removed from the oven and 60 grams of glue solution are weighed in, well worked in with a spatula, and filled into molds according to the specifications for making cement briquets. I n 2 to 3 hours, when the mix sets up, the mold is removed and the briquet is dried on wire screening for 6 weeks in air at 60 per cent relative humidit'y and 25" C. The briquets are then broken in a Riehl6 cementtesting machine.
COMPARISON OF GLUESOF SAMEGRADEFROM DIFFERENT ?(fAKERs-h this series, in order to speed up the drying time, another form of briquet was used. I n setting up the mold a metal insert, 0.645 cm. ( l / 4 inch) thick, 2.54 cm. (1 inch) high, and 2.54 cm. long, was placed in the center and the mixture was filled in around this mold. When the glue had set up the insert was removed. This type of briquet attained its maximum strength after less than 2 weeks' drying. It must be remembered that the cross section of this type is just three-fourths that of the usual briquet. Table VI11 TENSILE BRIQUETSTRENGTH 2 3 Av. MAKER SAMPLEVISCOSITYSTRENGTH 1 Kg. Kg. Millipoises Kg./sq. cm. Kg. Kg. 240 258 246 248 A 1 111 781 B C
2 1 1
2 3
98 111 105 106 102
750 734 842 806 802
252 264 264 285 299
249 262 280 297 300
249 252 252 293 304
250 260 266 292 301
From Table VIII, which gives the viscosity and tensile strength of a series of glues, together with individual and average values of the briquet strength, an idea of the accuracy of the results can be obtained. 8 Cf. Bogue, op. cif., p. 526. where a maximum adhesive strength is shown at pH values in the neighborhood of 3.5 and 7.5.
Qctober, 1927
INDUSTRIAL A N D ENGINEERING CHEMISTRY Conclusion
The results point to the existence of wide differences in the adhesive strength of glues of the same grade obtained from different manufacturers. For instance, sample A-1 is higher and A-2 is lower in grade, as measured by viscosity, than samples C-I, C-2, or C-3. Yet the briquet strengths of samples A-1 and A-2 are approximately equal while thoseTof samples C-1, C-2, and C-3 are nearly 15 per cent
1193
higher. This. as well as the results of over two hundred other tests (not given here), shows the futility of relying on viscosity or jelly strength measurements alone for testing the suitability of glues for joints of the specific type. Whether these variations in the adhesive strength of glues actually depend on differences in the raw hide stock, or whether they are due to differences in the manufacturing methods of the respectire makers, is as yet undetermined.
Magnesium and Its Alloys' By John A. Gann and Arthur W. Winston THEDow CHEXICAI, COMPANY, MIDLAND, MICH.
Recent advances have changed magnesium from a laboratory product to an important engineering metal. Production and cost figures have shown steady improvement during the last five years. The relationship between compositions, microstructures, and properties of magnesium-base alloys are discussed. This information has been used to develop various Dowmetal alloys with particular combinations of properties. The foundry practice, as here disclosed, is a radical departure from that used elsewhere. It is based on the use of a flux,which protects the molten metal from deteri-
oration, gives a satisfactory refining method, and a simple casting procedure. Its economic value has been proved by years of commercial use. Many magnesium alloys are being fabricated by forging, rolling, and extrusion processes whereby the structures and properties are greatly improved. Adequate protection can be given magnesium alloys by paints, varnishes, and lacquers. Proper preparation of the surface insures good adhesion of the protecting coat. Magnesium alloys have a wide field of use in industries generally. Their ultra-lightness makes them of particular value in automobile and aircraft production.
....
M
AGNESIUM is rapidly winning recognition as a useful engineering material. Practically unknown before the war, except in the college laboratory, it is now assuming real commercial importance. Because it is the lightest metal known to science possessing properties of permanence and stability, magnesium has long been a material of interesting possibilities to engineers, but any commercial application on a large scale was forced to wait upon lower manufacturing costs and the development of highstrength alloys. Both of these preliminary steps have now been so far accomplished that the cost of magnesium today compares favorably with that of the older metals, and alloys are available possessing strength and other properties amply sufficient for their intended uses. Eventually, magnesium will find extended uses in industries generally, as well as those particularly concerned with automobile and aircraft manufacture. Production
Table I-Analysis Copper Manganese Silicon Chlorine Iron and aluminum Magnesium
of Commercial Magnesium Per cent 0.015 10.005
0 005~0.002
0.020 * 0 . 0 0 5 0.015 t0.005 0.025 * 0 . 0 0 5
99.92 1 0 . 0 2
The increasing use of magnesium is indicated in the domestic production statistics of the Department of Commerce, which include castings and other fabricated forms as well as ingot metal. As production increases, there is no inherent reason why magnesium cannot compete with aluminum on a weight-for-weight basis. Table 11-Yearly
Magnesium Production AVERAGEINGOT P R I C E PER
YEAR
POUNDS
1921 1922 1923 1924 1925 1926
48,000 60,000 125,000 128,000 245,000 322,660
VALUE $ 86,000 89,000 155,000 150,000 274,400 390,400
POUND $1.30 1.60 1.25 1.07 0.86 0.80
Magnesium may be commercially produced by electrolysis Table 111-Magnesium Production-1926 of a fused chloride or of a fused fluoride-oxide bath. CLASS POUNDS -411 European magnesium and the greater portion of that Castings 36,940 Tubing, wire, powder, etc. 50,710 now being produced in this country is made by the chloride Ineots 23 5.000 process. The development of a low-cost raw material toTotal 322,650 gether with modifications of European practice has made Magnesium Alloys the chloride process an economic success. Dehydrated magnesium chloride is now commercially available. This Magnesium forms alloys with most of the common metals has substituted continuous operation of the electrolytic cells except those of the iron and chromium groups. An excepfor the batch process required when using mixtures of MgClz tion occurs with nickel, which alloys with magnesium in all with NaCl or KCl. Still further advance was made when it became possible t o use a partially dehydrated magnesium proportions. Magnesium shows a very strong tendency to form interchloride. The metal thus produced is very pure, as shown by the metallic compounds, even with metals in the same group of the periodic system. I n general, these compounds are analysis in Table I. hard and brittle, but they do exhibit marked differences in Received August 30, 1927 their resistance to corrosion, melting points, solubility in
