JANUARY, 1936
INDUSTRIAL AND ENGINEERING CHEMISTRY
much as the iron samples varied considerably in their phosphorous, sulfur, silicon, and manganese contents, few comparisons could be made. More remarkable than the loss in weight comparisons were the differences observed in sensitivity to mixed acid containing increasing water contents. Industrially this point is important because of the tendency of the concentrated acids to attract water and form more dilute solutions a t the interface air mixture. It was found therefore that each steel "broke down" with vigorous gas evolution a t a definite concentration of water. The steels having a high carbon content lost their passivity only a t high dilutions, while the steels low in carbon "broke down" readily a t the lower dilutions. The steels containing 0.02 per cent carbon did not tolerate more than 5 per cent water without violent gas evolution, whereas the spring steels (0.95 to 1.05 per cent carbon) maintained their passivity in mixtures containing as high as 50 per cent water. The relative degree of resistance was invariably the samethe higher the carbon content, the greater was resistance to acid mixtures high in water. It is interesting to note that these tests give results quite different from the classical experiments in dilute solutions. It is important to realize the great difference in behavior when passivity is a factor.
Effect of Low-Alloy Steels Through the cooperation of several large steel producers, samples containing small additions of nickel, molybdenum, chromium, tungsten, vanadium, and copper were obtained and tested. A number of samples were also tested which contained the same amounts of carbon but varying amounts of manganese. In every case the samples high in manganese and sulfur showed higher losses in weight and a lower capacity for retaining passivity in diluted solutions than did the samples low in manganese and sulfur. The presence of all the other alloying agents tended to increase the resistance and retain the passive character of the steel, Steels with S.A. E. number 6145, 3120, and 2330, and special compositions, such as Toncan, Timkin 17-22, and D. M., showed excellent resistance and tendency to retain passivity. The table which follows shows a typical set of results for alloy steels exposed to 50-50 mixed acid. S . A. E. No.
C 7
1020
Spec. No. 1 Spec. No. 2 6145 2320 3120 3140
5 . A . E. No.
0.20 0.36 0.40 0.45 0.19 0.19 0.39
Si 7 -
1020
Spec. NO. 1 Spec. No. 2 6145 2320 3120 3140
o:is
Mn Per
S
P
0.43 1.70 0.91 0.68 0.43 0.65 0.68
0.026 0.100 0.120 0.029 0.025 0.035 0.025
0.016 0.020 0.018 0.023 0,010 0 019 0.016
Ni
Cr
cent
Per cent-----
.. ..
7
Loss O./sg. dm.
..
.,
0.63 0 . 1 7 (V,O'.15) 0:86 0.15 3.42 0.25 1.24 0:63 0.24 1.29 0.61
0.3888 0.3934 0.4110 0.1890 0,2248 0.3146 0.2570
Effect of Heat Treatment In order to study the effect of heat treatment on some of the samples, one series of low-carbon steels and another of highcarbon steels were subjected to test. All the samples were first annealed, and then half of each set was quenched in cold water while the other half was allowed to cool slowly in the furnace to room temperature. The oxide scale was removed and the tests were continued as previously. The following
31
table gives the data of one typical set of results in a mixture of 45 per cent nitric acid, 45 per cent sulfuric acid, and 10 per cent water a t 25" C.: Sample No.
Loss in 100 Hr. G./sq. dm. 0.2379 0.1730 0.2664 0.4712
Carbon Per cent
C D C D
0.08 0.87 0.08 0.87
(quenched) (quenched) ffurnace-cooled) (furnace-cooled)
The results always demonstrated that the quenched samples retained a more passive surface than the furnace-cooled samples. Microscopic examination revealed identical surface attack with no evidence of local-action pitting in any case.
Acknowledgment The liberal donations of steel and iron samples by Joseph T. Ryerson and Son, Inc., Republic Steel Corporation, American Sheet and Tin Plate Company, The Carpenter Steel Company, and the Timkin Steel and Tube Company are greatfully acknowledged. RECEIVED July
22, 1935
Terpene
Furoates J. N. BORGLIN Hercules Powder Company, Wilmington, Del. ENEARI ( 2 ) reported the preparation of the methyl, ethyl, propyl, isopropyl, and isobutyl esters of furoic acid. Zanetti and Kerr (4) prepared and determined the properties of furfuryl furoate. Zanetti and Beckman (3) prepared the n-butyl, n-amyl, n-hexyl, n-heptyl, n-octyl, sec-butyl, sec-amyl, and sec-hexyl esters of furoic acid. The fenchyl and bornyl esters of furoic acid are here described together with their properties, hydrogenation, and use as a plasticizer for cellulose esters.
Preparation FENCHYL FUROATE. One-hundred grams of furoic acid, 400 grams of fenchyl alcohol, and 50 grams of toluene were heated 40 hours at 160" C., so that the water of reaction would distill off and leave the reactants in an anhydrous condition. This was done by means of a short Liebig column. The residual toluene and excess fenchyl alcohol were removed by steam distillation. An 83 per cent yield of liquid fenchyl furoate was obtained which analyzed as follows: Acid No. Boiling point, 760 mm.
0.7
2750
c.
BORNYL FUROATE.One hundred grams of furoic acid, 400 grams of borneol, and 50 grams of toluene were refluxed, as described, for 40 hours at 160" C. The toluene and excess borneol were removed by steam distillation. A 91 per cent yield of a pale yellow, liquid ester was obtained which analyzed as follows: Acid No. Saponification No. Boiling point, 760 mm.
18 238 275O C.
HYDROGENATION OF FENCHYL FUROATE. Fenchyl furoate is readily hydrogenated catalytically in the presence of plati-
VOL. 28, NO. 1
INDUSTRIAL AND ENGINEERING CHEMISTRY
32
SCHoPpEn
FOLDTEBTER (CENTER)
FOB
TESTING PLASTICIZERS IN CELLULOSE DERIVATIVES, TOGETHER WITH OTHER TESTINGEQUIPMENT
num, nickel, etc. Platinum oxide (1 gram), as made by Adams ( I ) , was reduced in glacial acetic acid to the active catalyst, in a Parr hydrogenation unit. Then 51 grams of fenchyl furoate were added, and the hydrogenation was conducted under 45 pounds per square inch (3.2 kg. per sq. em.) gage pressure and room temperature for 3.5 hours. The resulting produet was filtered, water-washed, and dried; a pale-colored saturated ester, fenchyl tetrahydroiuroate, was obtained. From the volume of hydrogen nbsorbed, the hydrogenation wa.8 01.3 per cent complete. The refractive index is reduced and the colloiding value' is increased by hydrogenation as indicated : Fenohyl iwopte Fenchyl tetrahydrofuroat.
Refractive Index 1.5019 1.4790
Colloiding Vd"0 25 00. 38
The furoic acid may be hydrogenated prior to esterification to obtain esters identical to those obtained by hydrogenation of the unsaturated ester.
Properties The furoic acid esters of the terpene alcohols are pale yellow. limpid liquids which discolor on standing because of oxidation. They may be distilled a t atmospheric pressure without decomposition; however, i t is desirable to use reduecd pressure. The latter products are somewhat more stable to diseoloration than those distilled a t atmospheric pressure. These esters are soluble in organic solvents as benzene, alcohol, acetone, petroleum hydrocarbons, chlorinated solvents, etc. They are insoluble in water and do not hydrolyze. They are efficient solvents for resins as dammar, ester gum, etc. In the presence of alcohol they colloid nitrocotton and have plasticizing action. The hydrogenated esters are light-stable, have somewhat better colloiding action on nitrocotton, are efficient solvents for resins, are readily soluble in the usual organic solvents, and are not hydrolyzed by water.
Use with Cellulose Esters and Ethers The terpene iuroates and their hydrogenated products have definite plasticizing action when used with nitrocellulose, I Determined by dissolving 5 grams of sample and 0.5 gram R.S. I/> aecond nitrocotton in 10 cc, of 95 per cent alcohol and titrating with benzene until the start of precipitation.
cellulose acetate, and cellulose acetobutyrate. The terpene iuroates may be used in cellulose ether compositions, as well as with cellulose esters. The following formulations indicate the favorable action of hydrogenated fenchyl furoate as compared with dibutyl phthalate in nitrocellulose lacqoers: Material Nitrooellulose Ester gum Dammar Eydrogensted ienchyl furonte Butyl acetate miuene Dibutyl Dhthalate ~. Fence days Disooloration
-
-
POrm"l&---2 3
1 10 8
in
~
4
10 8
..
..
39
..
39
39 39
39 39
54 OK
59
80
44
..
.. ..
S
8 4
4 39
..
..
4
4
OK
OK
OK
For durability and discoloration, hydrogenated fenehyl furoate is fully as good as dibutyl phthalate with ester gum and also dammar. The terpene iuroates may be used in coating compositions with cellulose acetate or cellulose aeetobutyrate of the following approximate formulas: -Formula-
Material Celiulose soetate Cellulose metobutyrste
Fenohyi furoate Hydiogeusted fenchyi iuioste R e a y l 14
Solvent
1
2
6
6
4 i
4
88
z
88
3
4
b 4
6
4
i 88
e
88
The solvent used was of the following composition: Acetone Methyl ethyl ketone Ethyl aoetrte Methyl Celloadve acetate
25 eo
20 35
20
(1) Adams, Roger. et nl.. "Organic Syntheses." Vol. VIII. p. 92. New York, John Wiiay & Sons, 1928. ( 2 ) Gennari, Gair. chim. itol.. [ I ]2 4 , 2 5 3 (1894). (3) Zmotti and Beckman, b. Am. Chern. Boc.. 48.1067 (1926). (4) Zanetti and Kerr,Zbid.. 47, 1452 (1925). Rscmuao July 18, 1935.
