Oils from Resins by Distillation hosphoric Acid IRWIN A. PEARL
AND
WILLIAM M. DEHN
University of W a s h i n g t o n , Seattle, Wash.
be applied industrially. The method for total oil is as follows : In a 0.5-liter distilling flask are placed 50 grams of the powdered resin and a few cubic centimeters of water. The flask is connected with a dropping funnel and a condenser. A separatory funnel is used as a receiver. The flask is heated until some water distills, then 50 cc. of 85 per cent phosphoric acid are dropped in slowly while continuing to heat strongly. Oil and water distill into the receiver and, as the heating is continued, white fumes begin t o form. After all of the acid has been added, water is dropped in at such a rate as to avoid the evolution of copious white fumes. The addition of water, and distillation to the point of evolution of fumes are continued until no more oil is carried over by the steam. Advantageously the water collected in the separatory funnel is dropped into the distilling flask to carry over the oil. The oil is extracted with ether, poured into a weighed beaker, and concentrated by evaporation of ether on the water bath.
HILE studying the cause of spoilage of beer in wooden kegs whose interior walls had been coated with a certain rosin, it was found that this rosin yielded a larger percentage of oil than other and satisfactory rosins. Also it was found that, when distilled directly, "common rosin I" gave only 17 per cent oil. However, when it was distilled with phosphoric acid in accordance with the method described here, 80 per cent oil was obtained. Certain industrial and natural resins were then distilled by the latter method. A study of the data thus obtained showed no correlations of percentages of oil with melting points, acid numbers, or class of resin. When compared with methods of destructive distillation and of distillation with sulfuric acid the phosphoric acid method showed certain advantages. For example, Schultze (6) obtained 60 per cent oil by dry distillation of American rosin. From kauri resin by dry distillation Rennie (5) obtained 10 per cent oil;IAndBs_(l),24 per cent; Wallace (Y), 40 per cent.
I n Table I the weight of the oil is reported as percentage of the weight of the original material used.
TABLEI Name
Class&
M. p.b O
c.
Oil0 as % Acid No. of Resin
Below 200' C. % Colord
..
..
Common (wood) rosin I I 69 156 80 Common rosin I1 I 56-74 156 67 1 Y I 101-125 ... 61 13 Y Kauri I 93-110 33 56 Dammar I 77-94 57 65 '2 k' Mastic I 97-117 128 66 2 Y Copal I Decomposed 50 55 12 Br White shellah I 128-132 21 18 36 A Jalap I 130-145 132 70 6 A Sandarac I 67-81 57 11 26 A Guaiacum 121 201 21 Y I1 80-90 Tolu I1 ..... GO 66 21 Y Storax I11 82-98 158 56 2 A Gum rosin F I11 80-98 158 70 . . Gum rosin G I11 7 1-89 155 81 5 Y Gum rosin 2 27 11 Br I11 125-149 Ammoniac I 74-76 3 Benzoin 88-110 0.4 Gambier iIi ... 0.0 Myrrh a I = resin; I1 = oleoresin: 111 = gum resin. b Determined in sealed capillary tubes. c After 3-year exposure to atmospheric oxygen, these oils showed little ?r no resinification. d A = amber; B = black; G = green; S = sohd or semisol!d: V = violet: Mr = colorless: Y e Because of decomposition these fractions were not distilled above 275' C . I Benzoic acid (18%) distilled before oil appeared.
Oil Fractions 200-275' C . 275-350O C. % Color % Color
25
45 54 35 28 8 23 '5 25 30 13 13 18
'is
.....
Over 350" C. Color 19 8
%
...
Easterfield and McClelland (3) obtained 40 gallons of oil per ton of kauri resin. Guedras (4) obtained oils from copals by dry distillation. Von Buyen (8) described a process of heating rosin with sirupy phosphoric acid to 260" C. until effervescence ceases. Since the present method yields a preponderance of oils boiling above this temperature, after being carried over by steam, the composition of the oils from the two processes differs. Owing to the fact that phosphoric acid can easily be recovered for reprocessing, this method can
=
yellow: / = 5uorescent.
Literature Cited And&, Farben-Ztg., 27, 92 (1921). (2) Buyen, E. von, German Patent 210,830 (1908). (3) Easterfield and McClelland, Chemistry and I n d u s t r y , 42, 936 (1)
(1923). (4) Guedras, Compt. rend., 135,797 (1902) (5) Rennie, J Chem. SOC.,39, 240 (1881) (6) Schultze, Ann., 359, 129 (1908). (7) Wallace, Ibid., 271, 309 (1892).
RECEIVED September 25, 1937.
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