GLEN W. HEDRICK and RAY V. LAWRENCE
U. S. Department of Agriculture, Naval Stores Research Station, Olustee, Fla.
From t h e Pi ley
Woods. .
.
IPINONBC ...a
Prom sing Chemical Raw M a t e r i a l
This versatile compound has potentialities for
b b b
plant hormones mercerizing penetrants synthetic lubricants
PINONIC
acid (111) was first prepared by Baeyer (3) in 1896 in developing the structure for a-pinene. Some time later DuPont (70) gave a more complete description of the structures of the various isomers. Numerous other workers (5,9, 72), including industrial firms, have investigated this material, but it has never been made commercially. Pinonic acid should be given careful consideration as a chemical raw material as it can be made from a-pinene (I), an available, replenishable, raw material-the major constituent of all American turpentines. I n 1957, estimated turpentine production (35) was 213 million pounds; a-pinene content was about 150 million pounds. Almost one third of the turpentine was consumed in retail sales in competition with petroleum solvents. Pinonic acid can be obtained by ozonolysis or permanganate oxidation of a-pinene. The Naval Stores Research Station studied the ozonolysis (71) and later sponsored research a t Armour Research Foundation (76). I n recent work (7), 65 to 70% yields of pinonaldehyde, 2,2-dimethyl-3-acetylcyclobutane acetaldehyde, were reported from the ozonolysis of a-pinene. King (78) obtained 80% yields of desired products from cyclohexene and norborene by use of halogens for decomposition of the ozonides. Because of the reactive acetyl and carboxyl groups in its structure, pinonic
b b b
plasticizers amino and dibasic acids polyesters
acid is a reactive chemical undergoing many of the reactions of a methyl ketone without rupture of the cyclobutane ring. This report describes a number of these reactions which give new compounds not yet evaluated. There are many more reactions of this type which have not been investigated. I n those instances where rupture of the ring has been observed, several interesting compounds are reported. An evaluation of production costs for pinonic acid is included to indicate its competitive position as a chemical raw material.
Cost Considerations Good yields of pinonic acid by application of the techniques of the later workers (7, 78) are indicated. With this expectation, materials costs have been estimated (Table I) using yield figures of 70 and on a-pinene and ozone. For oxidation cleavage of the ozonide, the cost of 1 mole of chlorine per mole of pinonic acid has been used in the calculations. At this station, small pilot plant quantities of pinonic and pinic acids have been produced over the past several years by permanganate oxidation of a-pinene using a 100-gallon, agitated, stainless steel kettle, a 20-inch centrifuge, and a couple of stainless steel, portable 50-gallon cans (21, 36). (The work involved commercial, optically active a-pinene, and these are the
Some 50 million pounds of a-pinene, currently being disposed of through retail outlets as a solvent, is available yearly for utilization as a chemical raw material. Conversion of a-pinene by ozonolysis or permanganate oxidation to pinonic acid may improve its utility and create new markets for its distribution
first reports describing use of dl-u-pinene on a large scale to prepare pinonic acid.) From 34 pounds (0.25 mole) of apinene and 80 pounds (0.505 mole) of potassium permanganate, 28 pounds of pinonic acid (61y0 yield) and 10.5 pounds of by-product 1-hydroxypinocamphone (11) (25y0 yield) have been obtained. The latter can be oxidized (30) by acid permanganate to give another 10 pounds of acid which raises the yield to 83YG Materials cost calculations for pinonic acid (Table 11) are based upon experience to date. Pinic acid (XVIII), a dibasic acid, has been obtained from pinonic acid by hypohalite oxidation. Cost figures (Table 11) based upon small pilot plant operations, 85% yield, are considered for this product as it i s among the chemicals with potential uses discussed later. Because approximately 1 mole of chloroform is produced per mole of pinic acid, the cost values for the acid can be reduced by about 11 cents if credit (15 cents per pound) is allowed for the chloroform. The materials cost figures in Table I 1 'ivere calculated using a zero cost for pinonic acid. T h e estimated pinic acid costs are shown. The estimated materials costs forpinonic acid vary from 13 to 66 cents per pound. Using these vaiues for pinonic acid, the materials cost for pinic acid, with credit for chloroform, ranges from 12 to 7 3 cents per pound. Either route (Tables I, 11) appears suitable for industrial exploitation to VOL. 52,
NO.
10
0
OCTOBER 1960
853
,,I..
Table I.
Materials Cost for Pinonic Acid via a-Pinene Ozonolysis Depends Upon Reaction Yield and Ozone Price Total AIaterials Co&a $ Ozone at Ozone at Material Amount.a Lb. Cost/Lb., $ 10.15/lb.b 80.50/lb.'
x
A
8o
caurtic soc3 COYS! c sodo c w d i f for chloroform Lime Lime credit for ~hloro'orm
v)
70% Yield on Ozone and a-Pinene
105.5 Ozone 37.2 37.2 Chlorine 38.5 T o t a l m a t e r i a l s c o s t / 1 0 0 lb.
0.07 0.15 0.50 0.045
cr-Pinene
7.3850 5.5800
7.3850
1.7325 14.6975 0.1470
18.6000 1.7325 27.7175 0.2772
...
...
Materials costjlb. pinonic acid
80% Yield on Ozone and a-Pinene
92.4 32.6 32.6 33.7
a-Pinene Ozone Chlorine
0.07 0.15 0.50 0.045
6.4680 4.8900
Price depends upon hize of production facility.
produce both acids a t prices low enough to attract chemical consumers.
to use dl-a-pinene which was prepared by mixing- a-pinene from sulfate tur-
pentine with a-pinene from gum turpentine. The former is usually rich in the d- form and the latter in the L-form. I n addition to the possibility of having a mixture of optical and dl-isomers, the cis- and trawisomers of pinonic acid (111) and (IV) are also possible. Permanganate oxidation of dl-a-pinene by the permanganate method described above gave only cis-dl-pinonic acid (melting point, l05O C.)>with no liquid tmnsisomer. Some authors, including Simonsen (5, 12, 29),have assumed that the solid product has the trans- structure.
Pinonic Acid Isomers T h e oxidation step of a-pinene is discussec) here in relation to the type and quality uf products obtained. Depending upon its source, a-pinene is usually enriched in either the d- or l-hydrocarbon and is rarely a dl-mixture without blending. Oxidation of a n optically active mixture gives a mixture of optically active pinonic acid (melting point 68' C). and di-pinonic acids (melting point, 105' (2.). To avoid this mixture of acid., it has been desirable
03
e
-
K M n O4
H O0Z 6 = O trons-dQ -Pinonic Acid, iquid liquid
ccis-di? i --Pinonic -
6-Pinene dg- 6
I
Acid,rn p 105°C AI W W
n n
o o
4 4
16.3000 1.5165 24.2845 0.2428
1.5165 12.8745 0.1287
M a t e r i a l s cost/lb. p i n o n i c a c i d
Required for 100 lb. of pinonic acid.
..
...
Total m a t e r i a l s c o s t a
6.4680
"'
P
IV
1-Hydroxypinccamphone -7
I I
$ O -& ;
-qio
NH3
-__c f
S
Alkylond HOC ( C H P ) ~ C H C H ,Vinyl ~ Esters
f?
Willgerodt
CH3C ;: >G=O CH3 0
Enol
VI
Hornoterpenyl Methyl Ketone
3-(3-carboxyprcpyl)-4~hydroxy-4rnethylvoleric a c i d V -lactone
V
VI1
H & N ,/ I
\
CH,-C
/ ,o,c=o
CH 3 2,4-Dimethylphenylocetic acid
X
3-(2-Acetarnidoethyl)- 4-hydroxy- 4 rnethylvaleric acid V-lactone
VI11
854
INDUSTRIAL AND ENGINEERING CHEMISTRY
__jc
U
H,C-C-CH3 I OH 4-(l-Hydroxy -I.methylethyU-2-piperidone IX
O
-
d
IO
l
L 1 20
PRICE
-
l
30
~
40
50
~
60
L
70
PER POUND PlNONlC ACID, CENTS
Materials cost for pinic acid (85y0 yield on pinonic acid) ranges from 12 to 93 cents per pound with chloroform credit Probably the best evidence in favor of the czs-assignment for this isomer (111) is in its unequivocal formation by the periodate oxidation of l-hydroxypinocamphone (11) in neutral aqueous solution (32).
Pinonic Acid Products Previous Work. A large proportion of the earlier work was concerned with the s t r u c u r e of pinonic acid. Only in a few cases was the acid used as an intermediare in preparing other chemicals. .4rcus ( 7 ) has studied the rearrangement of pinonic acid into homoterpenyl methyl ketone (V), a reaction first observed by Baeyer (4) who postulated the enol (VI) as the precursor to the reaction. Barbier and Grignard (6) prepared 2,4-dimethylphenylacetic acid (X) by heating pinonic acid in a sealcd glass tube M ith a molar equivalent of bromine in water. This work has recentlv been repeated in this laboratory to obiain the acid in 70Yc yield for evaluation as a plant hormone. A mechanism for conversion of pinonic acid into the phenylacetic derivative recently has been proposed by Harispe (18) and Arcus and Bennett ( Z ) , in which the lactone structure is considered an intermediate. Thoi (34)has published the most comd e t e recent studv on the chemistrv of pinonic acid in xvhich much of the earlier work was substantiated. He found that the acid did not undergo clean reactions with salicylaldehyde, ; however, isatin and substituted isatin gave good yields of a chinchoninic acid ( X I I I ) easily convertible to the corresponding quinoline derivative (XIV). Ruzicka (28) has prepared pinonic acid cyanohydrin (XI) in good yield and converted it to 5 isopropyl - 2 - methylheptanedioic acid ( X I I ) .
-
P l N O N l C ACID Developed at Naval Stores Station. Pinonic acid has becn convcried to s,m-homopinic acid (X\.II) by the \\'illgerodt reaction ( 3 0 ) . By the same mcihod, homoterpcnyl merh>,l ketone has been converted IO the valeric acid y-lacronc (VII) (73). S c w amino compounds have resulted from reactions of cis-dl-pinonic acid and homoterpenyl methyl ketone with hydrazoic acid (VIII, I X , XV, XVI) (25). Harispe and Pernin (75) prepared the amine (XXIV) by the hydrogenation of pinonic acid oxime. Pinonic acid has been evaluated as a mercerizing penetrant. When mixed with butyl Cellosolve, it is an effective wetting agent for cotton in strong caustic solutions and compares favorably with cresylic acid-butyl Cellosolve mixtures under some conditions (37). Pinic acid esters ( X I X ) have been evaluated as synthetic lubricants (24). Esters from normal alcohols containing 4 to 10 carbon a t o m compare favorably with the sebacate esters for this purpose. Hexyl and octyl esters are similar to di-2-ethylhexyl phthalate in plasticizing poly(viny1 chloride) (8, 27). In this comparison, esters of two other terpene acids, sym-homopinic acid ( X V I I ) and the valeric acid lactone ( V I I ) , were found to be similar to phthalate plasticizer. Lauryl and tridecyl pinonates are plasticizers for poly(viny1 chloride) (33) and may turn out to be superior to the pinate esters in that the pinonates have better over-all compatibility. Their plasticizing effect is compared with that of di-2-ethylhexyl phthalate in Table 111. As plasticizers for poly(viny1 chloride), neither pinonic nor pinic acid can compete economically with phthalic anhydride. However, they may be able to compete with some other commercially available acids. Table IV compares the required selling price of pinonic and pinic acid if tridecyl pinonate and di2-ethylhexyl pinate are to compete with 2-ethylhexyl alcohol esters of adipic, azelaic, and sebacic acids as plasticizers for poly(viny1 chloride). Pinic and sym-homopinic acids have been evaluated as raw materials for synthetic polyesters. Homopoly(ethy1ene pinates) are low-melting resins with no desirable properties. However, when used in interpolyester systems they act as internal plasticizers and can be used to advantage in controlling the properties of the system (36). Poly(ethylene biphenylcarboxylate) is a high melting solid. From 40 to 60 mole pinic acid in the polymer gives transparent films and good filament formation properties; 10 to 20 mole pinic acid in poly(ethy1ene terephthalate) reduces the melting point of the
pol!mcr \\.ithour destro)Ving the filmand fiber-forming properties. Homopinic acid gives results similar to diose obtaincd with pinic acid. Pinonic acid reacts \cith acerylene to gi\rc the expectcd acet),lcnic alcohol ( X X I I I ) (17).
Table II.
The difference in the reacti\*ir). of thc carboxyl groups of pinic acid distinguishes it from tnost commercially available dibasic acids. Half hydrolysis of diesters or direct inonoesterification affccts principall>, the acetic acid carL\VO
These Estimated Materials Costs for Pinonic and Pinic Acids Are Based on USDA Pilot Plant Experience Total Materials Cost, $ KMn04 at KMn04 at Amount," Lb. Cost/Lb., $ $0.20/Lb.b $O.%/lb. Pinonic Acid by KMn04 Oxidation
Material
0.07 0.20 0.28
86.4 215 215
a-Pinene
KMnOn
6.048 43.000
...
...
T o t a l cost/100 lb. Cost/lb. pinonic acid
60.200 66.248 0.6625
49.048 0.4905
Total Materials Cost
Pinic Acid, 85y0 Yield" 116.4d 134.7d 177.0d 164.0d
Pinonic acid Chlorine Caustic soda Lime
6.048
...
0: b45
... ...
6.062 8.850
0.05 0.01
6.062
...
1.640 7.702 0.0770 0.1128 0.0358
14.912 0.1491 0.1128 0.0363
T o t a l cost/100 Ib. Cost/lb. pinic a c i d Credit for chloroform N e t cost/lb. p i n i c a c i d
Required for 100 lb. of pinonic acid. Based on large-volume usage. Required for 100 lb. pink acid. cost of pinonic acid. Q
HcT
CH,
2,2-Dimethyl-3 -(I-ethynyl-l-hydroxy~thy1)-cyclobutaneocetic acid XXlll
Acid XI1
\
Pinonic Acid \Cyanc$ydrin
,, 3-Acetamido-2,2-dimethylcyclobu lane acetic Acid
-
xv
CHCHeCOH CH,FCH, H
SOH
Pinolic Acid XXll
x
8
HOC GI1 (CH,), I
Exclusive of
.
/
-
._cvclobulaneacetlc . -..iyl)-Z,Z-dimethylacid
Isatin O=bOH Chinchoninic Acid Xlll
,
XVI
"0°
HOCCH,
CH,SOH
sym-Homoplnic Acid XVll cis-d&- Pink XVlll
Acid
Acetate Form Monoalkyl Pinate
Formate Form Monoalkyl Pinot0 XXI
VOL. 52, NO. 10
OCTOBER 1960
855
Literature Cited
Table 111.
Plasticizing Effect of Some Esters of Terpene Acids Pinonates have better over-all compatibility Vinylite VYDR Copolymer l’oly(viny1 Chloride). Geon 101 Tensile 100% Elon- Brittle Tensile 100% ElonBrittle strength, modu- gation, point, =trength, modu- gation, point, p.s i. Ius TO C. p.s.1. lus % c. Plasticizer, 35% Lauryl pinonate 2730 320 -41 2820 1480 330 -39 1430 Tridecyl pinonate 2870 1490 350 -29 3050 1580 350 -31 Dihexyl pinate 2740 300 -49 2950 1530 300 -48 1330 Dioctyl pinate 2670 1490 320 -54 2180n 1650a 170a -32‘ Dihexyl homopinate 2810 1260 360 - 52 2890‘’ 1470b 300” - 51b Octyl valerate lactonec*d 3260 1590 330 -23 2970 1370 320 -35 3040 1550 330 -33 3110 1820 260 -36 Control-DOPe Tendency toward incompatibility. Dihexjl sum-hoinopinnte used. ‘ 30%Octyl ester of VII. 0 Di-2-etliylhexyl phthalate. OH GH,-
CH (CH,
)2
I;HC,H~
6-Hydroxy-3-(l-hydroxy-l-methylethyl)heptanoic ocid U -ioctone XXVI
I XXll
RoH
I \ I \
3-0- Acyloxyethyl)-2,2- dimethylcyclobutaneocet ic acid
Alkyl
and Vinyl Esters
xxv
i
n
CH,CoH
\
2,2,3-Trimethyl-4-hydroxy-
cyc lopentaneace tic acid
w
XXIX
CHpCOH pi n o
- Campholenic
Acid
XXVllI
boxyl group (79). This has made possible the preparation of pure monoesters, the formate (XXI) and acetate ( X X ) forms, each free of the other. Pure mixed esters and ester amides have been prepared from them. Catalytic reduction of pinonic acid yields the hydroxy acid, pinolic acid ( X X I I ) . This can be esterified with acids (XX\’) and,’or alcohols ( X X V I I ) ; however, reaction conditions must be carefully controlled to avoid side reactions. I n addition to low-molecular weight interpolyester formation, rupture of the cyclobutane ring has been observed, thus producing lactones ( X X V I ) and compounds having a cyclopentene ring ( X X V I I I , X X I X ) (27). The U. S. Department of Agriculture has a contract with the University of Illinois to study the polymerization of vinyl monomers derivable from farm commodities. Among the monomers
856
INDUSTRIAL AND ENGINEERING
studied are a number of vinyl esters derived from pinonic and pinolic acids, monoalkyl esters oi‘ pinic acid, and valeric acid lactone ( l 7 1 I ) (20, 26). Copolymers of thesr with vinyl chloride were essentially rigid plastics (22, 26). All the monomers polymerized to give homo- and copolymers having high molecular \veights. These were evaluated for internal plasticization only.
Table IV. Terpene Acids Can Compete with Commercial Dibasic Acids, Except Phthalic, for Plasticizer Use Required Competitive conlIllerciai Price of Terpene Acid, Dibasic $/Lb. Pinonic Pinic Acid 0.296 0.347 Adipic 0.36 0.399 Azelaic 0.667 Sebacic 0.593 0.033 Phthalic 0.041
CHEMISTRY
(1) Arcus, C. L., Bennett, G. J.. J . Ciim7. Soc. 1955, p. 2627. (2) Zbid., 1958, p. 3180. (3) Baeyer, A., k e r . 29, 3 (1896). (4) Zbid., p. 326. ( 5 ) Barbier. P., Grignard, V., Comfit. rend. 147, 597 (1908). (6) Zbid., 148, 646 (1909). (7) Chem. Eng. LVews 37, 52 (Sept. 28, 1959). (8) Conyne, R. F., Yehle, E. A., IND. ENG.CHEM.47. 853 (1955). (9) Delepine. M.’. B d l . sot: chiin. France [5] 3, 1369 (1936). (10) DuPont. G.. Brus. G.. Anit c4i.n. 19. 186 (1923). (11) Fisher. G. S., Stinson, .J. S.; IND. ENG.CHEM.47, 1569 (1955). (12) Grandperrin. M., Ann. chim. 6, 5 11936). ( 1 3 ) Halbrook, N. J., Lawrence, R. V., Naval Stores Station, Olustee, Fla., unpublished results (1956). (14) Harispe, M., Boime, A.: Ham, P.. Charonnat, R . , Bull. SOC. chim. France 25, 478 (1958). (15) Harispe, M., Pernin, .J., Ihid., 17, 660 (1950). (16) Holloway, F., Anderson, H. J., Rodin, W., IND.END. CHEM.47, 2111 ( 1955). (17) Howell: H., Hedrick, G. W.,Naval Stores Station, Olustee, Fla., unpublished results (1957). 118) King, L. C., Farber, Hugh, Abstracts, 136th Meeting, ACS, Atlantic City, N. .T., Septrmber 1959, 89P. (19) Lewis, J. B., Hedrick, G. W., J . Org. Cilem. 24, 1870 (1959). (20) Zbid., 25, 623 (1960). (21) Loeblich, V. M., Magne, I?. C., Mod, R. R., IND.ENC. CHEM.47, 855 (1955). (22) Marvel, C. S.? Shimuro, Y . , Magne, F. C., .I.Polymer Sci., in press. (23) Marvel, C. S., Vessel, E. D., Magne, F. C . , Ibid., 36, 35 (1959). (24). Murphy, C. M., O’Rear, J. G., Zisman, W. A., IND.ENG. CHEM.45, 119 (1953). (25) Parkin, B. A , , Hedrick, G. W., .I. Am. Chem. SOC. 80, 2899 (1958). (26) Parkin, B. A., Hedrick, G. W., ,I. Org. Chem., in press. (27) Parkin: B. A . , Hedrick, G. W., Naval Stores Station, Olustee, Fla., unpublished results (1958). (28) Ruzjcka, L., Trebler, H., Helu. Chim. Acta 3, 762 (1920). (29) Simonsen, J. L., Owen. L. N., “The Terpenes,” 2nd ed., Vol. 11, p. 147, Cambridge Univ. Press, Cambridge, 1949. (30) Stinson. J. S., Lawrence, R. V., J . Ore. Chem. 19, 1047 (1954). (31) -Summers: H. B., Jr., Hedrick, G. W., A m . Dyestuff Reptr. 47, 571 (1958). (32) Summers, H. B., Jr., Hedrick, G. W., Naval Stores Station, Olustee. Fla., unpublished results (1957). (33) Summers, H. B., Jr., Hedrick, G. W., Magne, F. C., Mayne, R. Y . , IND. ENG.CHEM. 51, 549 (1959). (34) Thoi, I,. V., Ann. chim. IO, 35 (1955). (35) L. S . Department of Agriculture, Agricultural Marketing Service, Washington, D. C., “Turpentine and Rosin and Related Data,” 1958-59 Annual Report. (36) Wielicki, E. A., Boone, C. J.: Evans, R. D., Lytton, M. R., Summers, H. B., Jr.: Hedrick, G. W.: J . Polymer Sci. 38, 307-18 (1959). RECEIVED for review February 4, 1960 ACCEPTED June 16, 1960
