INDUSTRIAL AND ENGIKEERIXG CHEMISTRY
OCTOBER. 1935
hardened tantalum. This use of the metal 1- due to the resistance of tantalum to the erosion of gases under high velocities. Calorimeters of complicated design for special purposeb have been constructed entirely of tantalum.
Tantalum Carbide in Hard-Carbide Compositions In addition to the many uses of tantalum in the pure metallic condition, tantalum carbide is now being employed in considerable quantities in the manufacture of hard carbide compositions for cutting tools, wire dies, and abrasion-resisting wrfaces. These compositions in general consist of particle>of a refractory carbide cemented with a binder metal, usually
1169
either iron, cobalt, or nickel. Such compositions, consisting almost entirely of tantalum carbide, are especially raluable for the turning of steel since they do not develop t,ool deterioration, known as cratering, on the t'op of the tool; this defect' rendered the earlier known tungsten carbide compositions impracticable for use on steel. Other compositions containing mixtures of tantalum carbide and tungsten carbide in varying proportions are also manufactured for use in niachining metals of various types and under varying conditions. RECEIVED April 27, 1935. Presented as part of the Syniposium on Recent .Idrances in the Chemistry of the Rarer Elements before t h e Division of Physical and Inorganic Chemistry at the 89th Meeting of t,he ;\nierirnn Chemical Society, New York, N. Y . , April 22 t o 26, 1935.
Lacquer Solvents in Commercial Use ARTHUR IC. DOOLITTLE Carbide and Carbon Chemicals Corporation, South Charleston. W. Va.
The technology of lacquer formulation is slowly emerging from the trial-and-error stage wherein the necessary information can be gained only by recourse to empirical methods, to a level which approaches the dignity of a science. The immense amount of data amassed both in the laboratories of the lacquer manufacturers and those of the raw material suppliers is now becoming digested and assimilated, and efforts are being made both here and abroad ( 6 , 1 3 ) to regiment the important facts and theories in the orderly arrangement of an exact science. I t is in the hope of contributing to this effort that this article is offered.
S
0 MUCH has been published in recent
years on the subject of lacquers sndlacquer solvents that the author ventures with considerable reluctance to offer still another r6sum6 of lacquer holvent technology. The consideration which prompted this htudy, however, is the fact that a wide divergence exists among the published values of the constants of lacquer solvents, and in no cases have the relative properties of all of the commonly used solvents been grouped together in a convenient and accessible form for the use of the lacquer formulator. Many of the data presented here were collected in the regular course of the work of this laboratory in evaluating new products and making comparisons with the commercially available products of other manufacturers. I n some cases, where the published methods of making certain determinations failed to provide the degree of reliability desired, modifications were worked out to improve the precision of the measurements. Lacquer solvents may be roughly defined as the volatile liquid ingredients of lacquers and as such include not only solvents for the nitrocellulose but also solvents for the gums, oils, and resins that enter into the composition of the modern pyroxylin finish.
Of particular interest, however, are the organic liquids that serve to disperse the nitrocellulose to form the sols commonly referred to as nitrocellulose solutions. These are, of cour-e, the so-called nitrocellulose solvents, and some insight into the cause of their solvent action may be gained by considering the structure of nitrocellulose itself. Calvert (3) has pointed out that the lacquer grade of pyroxylin contains approximately 58 per cent of oxygen as compared with only 30 per cent of carbon and hydrogen together. I t is not suprising to find, therefore, that practically all solvent\ for nitrocellulose are oxygen-bearing compounds. Several investigators hare attempted to correlate the solvent strength of nitrocellulose solvents with the proportion of oxygen-bearing groups in the molecule (5), or more simply, as Calrert ha\ done, with the percentage of oxygen present. il proportionate relationship holds accurately in the case of the normal 2ketones (Figure 1) but fails in may other cases, as has been pointed out by Davidson and Reid (4) and other..
-0 5 k
a z 4
0 k 3
2 3 n
6
8
10
I2
16 18 2 0 2 2 2 4 E 6 2 8 3 0 3 1 34 YO O X Y G E N - BY W E I G H T
14
'/.
A C E T O N E - 99% MLTHYL LTHYL KLTONL - 9 9 % MLTHYL PROPYL KETONE. 99% MCTHYLn-BUTYL K L T O N L - 9 9 %
METHYL n.AMYL KLTONL-98% MCTHYL nHCXYL K L T O N L
.9 9 %
TOLULNL F*MULAKIL'WT. 0 DILUTION RATIO C,H,O 5 8 . 1 27.6 4.5 C 4 H 8 0 7 2 . 1 22.2 4.3 C s H , o O 8 6 . I 18.6 4.3 C 6 H , r 0 100. I 16.0 4.0 C,H,,O I 14. I 14.0 3.3 C8H,bC I 2 8 . I I 2.5 3.6
FIGURE1. SOLVENT STREXGTH us. OXYGEXCOYTESTOF N O R M ~Z-KETONES L
.4n explanation of the degree of solvent ability is, therefore, not to be found in such a simple hypothesis as that "like dissolves like" in proportion to the percentages of the corresponding active groups or atoms present.
INDUSTRIAL, AND ENGINEERING CHEMISTRY
1170
VOL. 27, NO. 10
(00
90
80
70
n rJ
I-
4 60
a0
a 5c
J
5
Id
A0
U
a W a 3c 2c
10
0
4. 5. 6.
7.
8. 9. 10. 11. 12. 13. 14. 15. 16. 17.
TIME 111 HOURS (ATMOSPHLRIC CONDITIONS) RATES OF FASTTO IiVTERMEDIATE EVAPORATING LIQUIDS FIGURE 2. REL.4TIVE EVAPORATION 37. Methylcellosolve. . . . . . . . . . . . . . Methyl acetate.. . . . . . . . . . . . . . . . . . . 18. Solvesso S o . 1 . . . . . . . . . . . . . . . . . . . Acetone.... . . . . . . . . . . . . . . . . . . . . 19. sec-Butyl acetate. . . . . . . . . . . . . . . . 82% 38. Dipropyl ketone.. . . . . . . . . . . . . 39. Methyl amyl a c e t a t e . . . . . . . . . . 20. Hexone (methyl isobutyl ketone). . . 99 Methylacetone (acetone 48 per cent. . . . . . . . . . 96 40. Steam-distilled turpentine. . . . . 21. Isobut 1 acetate.. . methyl acetate 28 per cent, metha99 utyrate.. . . . . . . . . . . . . . . . . . . E t h y l g 41. n-Butanol .................... 22. nol 24 per cent). . . . . . . . . . . . . . . . . 42. nec-Amvl alcohol. . . . . . . . . . . . . . Cyclohexane. . . . . . . . . . . . . . . . . . . . . 23. Diethylcellosolve . . . . . . . . . . . . . . . . . 95 43. G i L s p i r i t i of turpentine.. . . . . . 24. Diethyl carbonate.. . . . . . . . . . . . . . . 91 Benzene . . . . . . . . . . . . . . . . . . . . . . . . . 44. Methyl n-amyl ketone. . . . . . . . . 99 2 5 , 8ec-Butanol. ...................... Ethylene dichloride.. . . . . . . . . . . . . . 99 45. Solveaso No. 2 . . . . . . . . . . . . . . . 26. Monochlorobeneene. . . . . . . . . . . . . . E t h y l a c e t a t e . . . . . . . . . . . . . . . . . . . . 85 46. Amyl alcohol, mixed isomers. . . . . . . . 27. 71-Butyl acetate . . . . . . . . . . . . . . . . . 90 99 Methanol (anhydrous). . . . . . . . . . . 86 47. Methyl amyl alcohol.. . . . . . . . . . . . . . Methyl ethyl ketone. . . . . . . . . . . . . 99 28. Mesityl oxide. .................... .... 48. Celloaolve .................... 29. Methyl n-butyl ketone. . . . . . . . . . . . 87 Isopropyl acetate. . . . . . . . . . . . . . . . 95 49. Methylcellosolve a c e t a t e . . . . . . . . . . . E t h y l propionate. . . . . . . . . . . . . . . . 30. Xylene.. . . . . . . . . . . . . . . . . . . . . . . . . . 96 50. Cyclohexanone. . . . . . . . . . . . . . . . . . . 99 31. Isobutanol. . . . . . . . . . . . . . . . . . . . . . . . Ethanol (anhydrous). . . . . . . . . . . . 99 51. Isopropylcellosolve . . . . . . . . . . . .... Methyl propyl ketone.. . . . . . . . . . . 32. Sec-Amyl a c e t a t e . . . . . . . . . . . . . . . . . . 92 99 Isopropanol (anhydrous) . . . . . . . . . Diethyl ketone.. . . . . . . . . . . . Petroleum n a p h t h a . . . . . . . . . . . . Toluene . . . . . . . . . . . . . . . . . . . . . . .
99
33. 34. 35. 36.
sec-Hexyl acetate.. . . . . . . . . . . . . . . . . 98 .4myl acetate, mixed isomers.. . . . . . . 84 n-Butyl propionate. . . . . . . . . . . . . . . . 99 Hi-Flash naphtha . . . . . . . . . . . . . . . . .
Theory of Solvent Action I n the case of true solutions, certain well-defined theories have been proposed, perhaps most clearly set forth by Hildebrand (9). According to these views, two classes of liquids are distingnished, referred to as nonassociated and associated liquids. The members of the first group, nonassociated liquids, have low dielectric constants and conform t o general rules concerning surface tensions and heats of vaporization. In this group are included the paraffin hydrocarbons, coal-tar hydrocarbons, and carbon tetrachloride. The members of the other group, associated liquids; have higher dielectric constants and exhibit higher surface tensions and heats of vnporixation than would be expected from the generalizations applying to
52. 53.
. ....
Hexyl (2-ethyl butyl) a c e t a t e . , Cellosolve acetate. . . . . . . . . . . . . . . . .
E;% 95
-
99 99
98 99 ~~
99 99 Q9 67 97 91 96
__
the first group. The associated liquids include such solvents as water, alcohols, ketones, and esters. The evidence indicates that the fundamental distinction between the nonassociated and associated liquids lies in the greater symmetry of the fields of force surrounding the molecules of the liquids of the first group. The fields surrounding the molecules of the associated liquids are considered to be unsymmetrical or polar. The result is that polar molecules have greater attraction for each other, thus producing greater cohesions, surface tensions, and heats of vaporization. It may therefore be visualized that substances having high internal pressures (cohesive forces) would act only as solvents of similar substances because the molecules of a substance of low internal pressure would tend to be “squeezed out” by the
OCTOBER, 1935
INDUSTRIAL AND ENGINEERING CHEMISTRY
0
1171
-
TIME HOURS (ATMOSPHERIC CONDITIONS) FIGURE 3.
REL4TIVE EVAPORATION RATES
%-Butyl acetate. . . . . . . . . . . . . . . . . Xylene.. . . . . . . . . . . . . . . . . . . . see-Hexyl a c e t a t e . . . . . . . . . . . . . riniyl acetate (mixed isr1:nere). . . . . n-Butvl Drouionate . ...... X e t h ~ l c ~ l l o $ o l v.e . . . . . . . . . . . . 7. Dipropyl k e t o n e . . . . . . . . . . . . . . . . . 8. Methyl amyl acetate. . . . . . . . . . . . 9. Steam-distilled turpentine . . . . . . . . 10. n-Butanol . . . . . . . . . . . . . . . . . . . . 11. sec-Amyl alcohol . . . . . . . . . . . . . . . 12. G u m spirits of turpentine.. . . . . . . . . . 13. .Methyl n-amyl ketone. . . . . . . . . . . 14. A4mylalcohol (mixed isomers). . . . . 15. Hi-Flash n a p h t h a . . . . . . . . . . . . . . . 16. Methyl amyl alcohol.. . . . . . . . . . . 17. Cellosolve. . . . . . . . . . . . . . . . . . . . . . . 18. hlethylcellosolve acetate . . . . . . 19. Solvesso KO.2 1. 2. 3. 4. 5. 6.
90%
-
20.
98
22. 23. 24. 25. 26. 21. 2s. 29. 30. 31. 32. 33. 34.
84
99 99 99
95
99 99
-
9s 99
99 99 99
21.
35. 36. 37. 38.
OF
IYTERMEDIATE TO
powerful attractive forces exerted between the molecules of the polar liquid. Application of the general theory of solubility t o the action of solvents in dispersing nitrocellulose to form colloidal solutions is, however, still a matter of speculation. An excellent discussion of the subject is given in a recent paper by Clayton and Clark ( 3 ) . These authors ascribe the polarity of the nitrocellulose molecule to a coordinate linkage between the hydroxyl groups and adjacent ester groups in the cellulose ester molecule. The well-known fact that pyroxylins of higher degrees of nitration are decreasingly soluble in polar solvents and increasingly soluble in nonpolar solvents such as chloroform lends credence to this view-.although direct proof in this manner is not possible because complete nitration with ex-
EVAPORdTING LIQUIDS Cyclohera:iyl acetate. . . . . . . . . . . . 40. Hercosol.. . . . . . . . . . . . . . . . . . . . . . . . 41. Hexyl (2-ethyl butyl) alcohol. . . . . . .
SLOW
Cyclohe*anone . . . . . . . . . . . . . . . . . 67% Isopropyloellosolve. . . . . . . . . 9 1 Hexyl (%ethyl butyl) acet‘ste.. . . . 91 Cellosolve acetate . . . . . . . . . . 96 E t h y l l a c t a t e . . . . . . . . . . . . . . 93 I\Iethylcyclohexanone . , . . , . 74 Butyl butyrate.. . . . . . . . . . . . . . . . . . 99 1’. &I, B P. n a p h t h a . , . . . . . . . . . . . . Diisohutyl k e t o n e . . . . . . . . . . . . . . . 95 Mineral spirits. . . . . . . Iaopropyl lactate . . . Furfural.. . . . . . . . . . . . . . . . . . . 98 Dipentene . . . . . . . . . . . . . . . . -o-Dichlorobenzene . . . . . . . . . . . . . . . . Diacetone a l c o h o l . . . . . . . . . . 99 3-Methoxy butyl acetaie . . . . . . . . . . 99 Methyl n-hexyl ketone . . . . . . . . . . . 96 Dichloroethyl e t h e r . . . . . . . . . . . . . . 99 Decahydronaphthalene. . . . . . . . . . --
39.
42. 43.
Phorone . . . . . . . . . . . . . . . . . . . . . . . . Butylcellosolve . . . . . . . . . . . . . . . . . . . Solvesso N o . 3 . . . . . . . . . . . . . . . . . . . 47. Cyclohexanol . . . . . . . . . . . . . . . . . . . . . Furfuryl a c e t a t e . . . . . . . . . . . . . . . . . Acetonylacetone.. . . . . . . . . . . . . . . . . SO. Tetrahydrofurfuryl alcohol 51. Diethylcarbitol . . . . . . . . . . 52. Furfuryl alcohol., . . . . . . . . . . . . . . . 53. Tetrahydronaphthalene. . . . . . . . . . . . :5. Ootyl (3-ethyl hexyl) acetate . . . . . . Rutyloellosolve acetate.. . . . . . . . . . . . DO. ....... 56. Butyl laotat ....... 57. Glycol diace 44.
45. 46.
94 99 95 99 99 98 99 99 97 99
tinction of all of the hydroxyl groups in the cellulose molecule has not been effected. Highfield (8) has adapted the polar-nonpolar theory of Hildebrand t o explain the action of acetone-mater mixtures on nitrocellulose, assuming that, in the case of the mixture of maximum solvent strength, the acetone-water mixture has the optimum polar characteristics for dissolving nitrocellulose. In an authoritative communication on this subject, Sheppard, Carver, and Houck (18) endorse Highfield’s views and advance a rational hypothesis to account for the greater solvent strength of mixtures compared t o that of their pure components. According t o these authors, an explanation of the increased solvent strength exhibited by certain mixtures of polar solvents, such as, for example, ether and alcohol,
INDUSTRIAL ASD ENGINEERING CHEMISTRY
1173
VOL. 27, KO. 10
TABLEI. PROPERTIES OF No.
Formula
Nol. Wt.
Boiling Rangea Initial End b. p. point
c. Ketones: 1 Acetone 2 Methylacetone 3
Methyl ethyl ketone Diethvl ketone Methyl propyl ketone Hexone (methyl isobutyl ketone) Methyl n-butyl ketone Mesityl oxide Diacetone alcohol Dipropyl ketone Methyl n-amyl ketone Diisobutyl ketone Methyl n-hexyl ketone Cyclohexanone Methylcyclohexanone Acetonylacetone Phorone
4
k
9
10 11 12 13
14 15 16 17
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
Polyethers: Diethylcellosolre Diethylcarbitol Esters:f hlethyl acetate E t h y l acetate Isopropyl acetate Isopropyl acetate E t h y l propionate sec-Butyl acetate Isobutvl acetate ;-Butyl acetate E t h y l butyrate sec-Amyl acetate Amyl acetate (mixed isomers) Butyl butyrate n-Butyl propionate Methyl a m 1 acetate Hexyl (2-etKyl butyl) acetate sec-Hexyl acetate E t h y l lactate Octvl (2-ethvl hexvl) acetate CyJoh'exanf1 acetate Isopropyl lactate R1rtvl GI-., ....laatatn ..... ycol diacetate Didycol diacetate Diethyl carbunare 3 - J I e t l ~ o s sbutyl acetate .\lettrslcellosolve acetate Cellosolve acetate Butylcellosolve acetate Methylcarbitol acetate Carbitol acetate Butvlcarbitol acetate
Ether alcohols: Methylcellosolve Cellosolve Isoprop~lcellosolve Butylcellosolve Rlethylcarbitol 56 Carbitol 57 Butylcarbitol 58 Benzylcellosolve 51 52 53
CH 48:
;;
CzHsOCHzCHzOCzHj CzH~OCHnCHzOCHzCHzOCzH~
8
200CzHs 'CHd(C3H7)
2 b V 3
:H(CHa) CHzCHzOOCCHz
CH30CHsCHzOH CsHsOCH2CHsOH (CH3)zCHOCHzCHzOH C~HBOCHZCHZOH CHoOCHaCHzOCHzCHzOH CzHsOCH&HzOCHzCHzOH C~HBOCHZCHZOCHZCHZOH CsHaCHzOCHzCH2OH
c.
c. -94.3 (12)
58.05
55
57
....
72.06 86.08 86.08 100.09 100.09 98.08 116.09 114.11 114.11 142.14 128.12 98.08 112.09 114.08 138.11
54 77 100 101 112 114 117 153 138 147 164 169 130 114 188 114
70 82 104 107 118 137 139 160 144 153 169 173 173 173 193 198
118.11 162.14
119 181
125 189
74.05 88.06 102.08 102.08 102.08 116.09 116.09 116.09 116.09 130.11 130.11 144.12 130.11 144.12 144.12 144.12 118.08 172.16 142.11 132.09 146.11 146.08 190.11 118.08 146.11 118.08 132.09 160.12 162.11 176.12 204.16
53 70 84 82 90 105 114 119 107 121 127 152 124 140 157 129 119 195 165 149 145 184 238 87 135 143 145 188 203 211 236
55 80 94 90 118 127 118 127 131 144 155 170 171 147 164 158 176 203 193 167 230 191 251 127 173 145 166 192 212 220 249
SA ne 90. 104.09 118.11 120.09 134.11 162.14 152.09
121 133 140 163 190 189 220 254
126 137 143 172 194 203 231 258
os
Melting Pointa
c.
.... -86.4
(1.2) -42 (IS) -77.8 (12)
-84.7 (IS) -56.9 (18) -59 (IS)
....
-32.6 (IS)
....
- 2 i : s (28)
.... ....
-9
28
(IS)
(IS)
- 9 8 . 1 (IS) -83.6 (12) -73.4 (IS)
....
.-72.6
....
(12)
-98.9 (18) -76.8 (IS) - 9 3 . 3 (IS)
.... ....
....
.... ....
.... ....
-31 -43
....
....
....
Flash PointC
(f2) (18)
0
23 34 59 60 74 95 90 135 120 115 145 160 145 145 190 180
Vapor Pressure a t 30' C.
M m . HQ 277 d
119 46
;; (
17 < 10 2 9 7 4 3 7 4
