Patented Aug. 20, 1935 2011,707

UNITED STATES PATENT OFFICE 2,011,707 PREPARATION of TERPENE ESTERS OF OCARBOXYTLICAC DS Joseph N. Borglin, Wilmington, Del, assignor to Hercules Powder Company, Wilmington, Del, a corporation of Delaware No Drawing. Application June 4, 1932, Serial No. 615,460 23 Claims. (C. 260-99) This invention relates to the preparation of with butanol. Other primary alcohols operate dibasic acid esters of secondary terpene alcohols similarly to complete the formation of a substan and more particularly to the preparation of both tially neutral ester. The mixed phthalate ob the mono- and di-phthalates of secondary terpene tained above apparently consists of borneol (or alcohols. fenchyl) neutral phthalate, dibutyl phthalate and 5. AS pointed out in the application filed by George borneol (or fenchyl) butyl phthalate. M. Norman, May 22, 1931, Serial No. 539,420, cel The reaction involved in this invention may lulose ester compositions containing esters of be desirably carried out in the presence of a suit phthalic acid, and more particularly the phthalic able solvent for the terpene alcohol. Suitable O acid esters of secondary terpene alcohols, give solvents will be non-reactive in the process, will 10 rise to films of exceptional hardness and resist be immiscible. With water and will have a boiling ance to abrasion having superior weathering qual range of about 75-200° C., or preferably of about ities and resistance to discoloration. In such 100-150° C. The solvent will preferably be a hy compositions either the neutral or acid esters may drocarbon as toluene, xylene, benzene, or other 5 be used. It is also found that secondary terpene aliphatic or aromatic hydrocarbon, though equiv- 15 characteristics.alcohol esters of other dibasic acids have similar alients therefor are contemplated. The presence It is the broad object of the present invention of the solvent will promote the elimination of to provide improved methods of preparing, both water liberated during the reaction, as will be 20 neutral and acid dibasic acid esters of secondary more particularly understood from the examples alcohols, and specifically the phthalic esters of given hereinafter. 20 Secondary terpene alcohols. Briefly, the improved The above outlines the general characteristics methods involve direct esterification of the alco of the reactions, not only for the preparation of hols with the dibasic acid or its anhydride, for phthalic esters but of other dibasic acid esters. 25 example, succinic, maleic, phthalic, tartaric, adip However, the details will be best understood by ic, oxalic, sebacic, glutaric, malonic, etc. acids or reference to the following illustrative processes 25 anhydrides under optimum conditions to obtain for the preparation of specific products. high yields and products of a high degree of Die-bornyl phthalate (bornyl neutral phthalate) purity. f To forty parts of borneol contained in a suit 30 It is found that a substantially neutral borneol able reaction vessel are added five parts of tolu- 30 phthalate can be prepared by treating phthalic ene. The mixture is heated until free from mois anhydride with about 40% excess borneol at a ture and then allowed to cool. The purpose of reaction temperature of 165-170° C. The result this is to thoroughly dehydrate the borneol in or ing product has an acid number of about 35, and der to promote the rate of esterification after the 35 contains approximately 20% of borneol acid subsequent addition of the phthalic anhydride. 3 phthalate. By admixing the borneol with toluene, xylene, When the same reaction is conducted at 200 or some other aromatic or aliphatic hydrocar C. the reaction product contains only about 5% bons of comparable boiling range, boiling of the of acid phthalate. mixture effects the substantially complete re The rate of reaction between excess borneol moval of the water. By condensing the evolved 40 and phthalic anhydride is about 80-90 per cent vapors and using suitable separating apparatus complete in about thirty hours when the reac the water may be removed from the distillate and tion takes place at 165-170° C. From this stage the hydrocarbon permitted to flow back into the on the reaction is quite slow. That is, by con reaction vessel for use. tinued heating for an additional forty hours the After removal of water, as above, 12 parts of 45 reaction progresses only a few percent further. phthalic anhydride are added. The mixture is Now butanol and other primary alcohols react then heated for about 84 hours at a temperature more rapidly with phthalic anhydride than borne of 165-170° C. During the progress of the reac ol or fenchyl alcohol. Accordingly, by conduct tion when the second carboxyl group of the 50 ing the reaction between borneol or fenchyl al phthalic anhydride is combined with the alcohol 50 cohol and phthalic anhydride for about thirty water is liberated and is carried over to the con hours and then adding butanol a mixed phthalate . denser with the toluene vapors, separation being results which is essentially neutral. That is, the then effected and the toluene being returned to resulting product is more neutral than when the the reaction vessel as already indicated. The re borneol phthalate is not caused to further react Sulting product is sparged with steam for the re- 55 2. 2,011,707 moval of hydrocarbon and unreacted borneol. boxyl esterified with borneol and the other car The remaining mass is then drawn off. A yield of boxyl by the fenchyl radical. 98.3% has been obtained by this process. The Miaced borngil-butyl phthalate product has an acid number of 8.6 and a melting point of 130-135° C. The borneol neutral phthal To 33.7 parts of dry borneol are added 12 parts ate thus produced readily colloided nitrocotton. of phthalic anhydride and 6 parts of toluene. This reaction, mass is then heated during one Mono-bornyl phthalate (bornyl acid phthalate) hour at a temperature of 165-170° C. At this To 200 parts of dry borneol (dried as indicated stage water of reaction begins to appear indicat above by boiling with toluene) are added 170 ing that one carboxyl has been esterified by the 0 10 parts of phthalic anhydride and about 100 parts borneol raucleus and that the other carboxyl of of toluene. This charge is heated during eight phthalic acid was beginning to be esterified. Ten parts of butanol are then added and the heating hours at a temperature of 165-170° C. The prod continued during another twenty-six hours. By uct is sparged with steam for removal of toluene 5 5 and borneol. The resulting product (yield about reason of this the second carboxyl is esterified 75%) consists primarily of mono-borneol phthal by the butanol group which esterifies the phthalic acid much more rapidly than borneol with the ate (borneol acid phthalate), has an acid num resulting production of mixed borneol-butyl ber of 116.2 and readily colloided nitrocotton in. phthalate. the presence of alcohol. The resulting product is sparged with steam 20 20 Di-fenchyl phthalate (fenchyl neutral phthalate) for removal of the volatile alcohols and toluene. To 25 parts of fenchyl alcohol are added about . The resulting product had an acid number of 100 parts of toluene. This mixture is then boiled 12.3, a caponification number of 165.6, melting in the manner indicated above for removal of point soft and colloided nitrocotton more readily 25 25 water. There are then added 75 parts of phthalic than borneol neutral phthalate. The latter com anhydride so that about 63% excess fenchyl alco pound when Saponified does not give a true Sapon hol is available. This reaction mass is heated ification number, the result being much too low. during 45 hours at a temperature of 165-170° C. In the case of butyl phthalate the saponification number is readily obtained by the standard meth The resulting reaction mass is sparged with 30 30 steam for the removal of volatile constituents and Od. Naturally, a mixed borneol butyl ester will is then drawn off into a suitable container. About give a higher saponification number than borneol an 89% yield of a product has been thus obtained neutral phthalate. By the above procedure esters having the following composition: . with acid numbers as low as one can be obtained. Percent The product representing. 99.4% yield of mixed 35 35 Fenchyl acid phthalate------22.7 borneol butyl ester apparently consisted of Fenchyl neutral phthalate------77.3 borneol neutral phthalate, butyl neutral phthal The above product has an acid number of 68 ate and the mixed borneol-butyl phthalate. and readily colloided nitrocotton in the presence Miced fenchyl-butyl phthalate of alcohol. To 400 parts of fenchyl alcohol were added 140 40 40 Mono-fenchyl phthalate (fenchyl acid parts of phthalic anhydride and about 100 parts phthalate) of toluene. This reaction mass was heated dur 189 parts of fenchyl alcohol and about 100 ing twenty-two hours at a temperature of parts of toluene are boiled to remove water. 165-170° C. At this stage water of reaction ap 45 45 There are then added 148 parts of phthalic an peared and about 10 parts of butanol were added hydride and the reaction mass is heated about 8 and the heating continued during an additional hours at a temperature of 165-170° C. The re eighteen hours. The resulting product was then sulting product is then sparged with steam for Sparged with steam for removal of volatile con removal of the volatile-alcohol and toluene. A stituents. The resulting product had an acid 50 50 67% yield of acid phthalate has been obtained by number of 17.2, a Saponification number of 188.3 the practice of this process, the product having and a melting point soft and readily colloided an acid number of 245 and a melting point of nitrocotton. The product apparently consisted of fenchyl neutral phthalate, butyl neutral phthal 102-103° C. and readily colloided nitrocotton. The latter late and the mixed butyl phthalate. 55 55 Miced fenchyl-bornyl phthalate compound would have the structure of phthalic To 600 parts of pine oil fraction, or a mother acid wherein one carboxyl is esterified by the liquor containing 37.5% secondary alcohols fenchyl nucleous and the other carboxyl by the (borneol and fenchyl alcohol) was added 50 butyl nucleus. - . parts of phthalic anhydride and about 100 parts The various neutral terpene phthalates men 60 60 of toluene. The reaction mixture was heated tioned above may be treated to remove acid during forty hours at a temperature of 165-170° C. phthalates and phthalic acid by reason of the The resulting reaction mass was then sparged fact that both phthalic acid and the acid for the removal of volatile consititents. The re phthalates readily react with alkali to give a Sulting product had the following composition: water soluble salt. On the other hand, the 65 65 neutral phthalates are substantially unchanged - Percent by cold alkali treatment although, of course, Acid phthalates------m ------19.3 Saponification takes place slowly if the neutral Neutral phthalates------80.7 phthalates are heated with alkali. After cold The product had an acid number of 38.2 and treatment with alkali the resulting mass is fil 70 70 readily colloided nitrocotton. The product ap tered whereby the alkali salts pass into the fil parently consisted of fenchyl and borneol acid trate and the-neutral phthalates are retained by phthalates, fenchyl and borneol neutral phthal the filter medium. By washing with water and ates and the mixed fenchyl-borneol neutral drying the neutral phthalate may be obtained in phthalate. This last compound has a structure Substantially pure condition. 75 which consists of phthalic acid having Orie car If the phthalates are made in iron equipment, 5. 2,011,707 3 the resulting product is contaminated with this metal resulting in an increase in color. This iron giving a 94% yield of very pale dibornyl suc can be removed by dissolving in toluene or other cinate, having an acid number of 14.5. Suitable solvent and heating with an alcoholic Di-bornyl or di-fenchyl maleate Solution of Oxalic acid, drawing off the spent alcohol Solution, washing with water, and evapo Dibornyl maleate may be similarly prepared rating the toluene or other solvent. The result by heating 125 parts of borneol, 25 parts of ing product is greatly improved insofar as color maleic anhydride, and 25 parts of toluene for 40 is concerned. hours at 140-150° C. After purification as above O Further purification of terpenephthalates may the product may be obtained having an acid number of 3.6. Difenchyl maleate may be pre 0. be effected by distillation under reduced pressure. pared in a similar manner. Instead of using For example, distillation of the neutral phthalate maleic anhydride, maleic acid may be used in may be effected from a bath maintained at a both cases. temperature of 200-300° C. under a pressure of 15 Mixed esters of the aliphatic dibasic acids may 15 mm. As a result of such distillation high be prepared by the same general methods used ields of the order of 97% may be obtained, the as above described for the preparation offenchyl distillate being quite light in color. bornyl phthalate, bornyl-butyl phthalate, or In carrying out the process indicated above the fenchyl-butyl phthalate. 20 toluene may be replaced by other hydrocarbons Other terpene alcohol esters of dibasic acids or neutral substances capable of dissolving a re may be prepared in similar fashions, whether 2) action mixture and having boiling points higher the dibasic acids are aliphatic or aromatic. Sub than the boiling point of water. For example, stituted dibasic acids give esters by methods xylenes may be used, also terpene hydrocarbons similar to those above, and it will be under 25 and cuts of petroleum hydrocarbons boiling at stood that in the following claims substituted approximately 100-150° C. acids are to be considered as equivalents of the While temperatures of the order mentioned in simple acids. the specific example are preferably used, tem . The various esters may be used in the manner peratures between 150° and 210° C. result in d2scribed in the Norman application above re 30 rapid esterification. Temperatures below this ferred to. range likewise result in esterification but at slow Since the dibasic acids or their anhydrides may 3 () er rates. A be used interchangeably in the production of To complete the neutralization of acid terpene esters in accordance with the invehtion, the phthalate, methyl, ethyl, propyl or amyl alcohols terms 'acid' and "anhydride' are used equiva 35 may be substituted for the butyl alcohol men lently in the following claims. tioned in the above examples. In the case of What I claim and desire to protect by Letters lower boiling alcohols the heating should be con Patent is: ducted under pressure so that high temperatures 1. The method of preparing a terpene ester, of may be used with resulting rapid reaction. a dicarboxylic acid including heating, at a tem 40 The processes described above are applicable perature above 100 C., a secondary terpene al to the formation of phthalic acid esters of other cohol. With the acid in the presence of a solvent secondary terpene alcohols besides those men for the reactants which is non-reactive in the tioned. However, borneol and fenchyl alcohol process, immiscible with water, and has a boiling have been specifically mentioned as reagents in point of from about 75 C. to 200° C. asmuch as their esters are of primary importance. 2. The method of preparing a terpene ester 45 The preparations of phthalic acid esters have of a dicarboxylic acid including heating, at a ten- : been considered in considerable detail since they perature above 100 C., a secondary terpene al 4. 5 are of primary importance and since they illus cohol with the acid in the presence of a liquid trate the details involved in the preparations Of aromatic hydrocarbon having a boiling point other esters of dibasic acids such as the borneol above that of water. 50 or fenchyl alcohol esters of succinic, tartaric, 3. The method of preparing a terpene ester of adipic, oxalic, sebacic, maleic, glutaric, malonic a dicarboxylic acid including heating, at a tem 50 and other disbasic acids. These acids or their perature above 100° C., a secondary terpene al anhydrides are readily esterified with borneol, cohol with the acid in the presence of toluene. fenchyl, or other terpene alcohol, toluene or 4. The method of preparing a terpene ester of 55 other suitable solvent being used to assist in the phthalic acid including heating, at a temperature removal of water of reaction and to promote above 100° C., a secondary terpene alcohol with 5 contact between the acid and alcohol. As ex phthalic anhydride in the presence of a liquid amples of the preparation of esters of dibasic aromatic hydrocarbon having a boiling point acids other than phthalates, the following may above that of Water. 60 be cited: 5. The method of preparing a terpene ester of phthalic acid including heating, at a tem 60 Di-bornyl succinate perature above 100° C., a secondary terpene al 200 parts of succinic acid, (for which the an cohol with phthalic. anhydride in the presence hydride may be substituted) 800 parts of borneol of toluene. v 85 and 100 parts of toluene are refluxed for 40 6. The method of preparing a bornyl ester of hours at 190-200° C., a short reflux column being a dicarboxylic acid including heating, at a ten used to permit part of the toluene to return con perature above 100° C., borneol alcohol with the tinuously to the reactants, washing down sub acid in the presence of a solvent for the re 70 limed borneol, the major portion of the toluene actants which is non-reactive in the process, being returned only from time to time after immiscible with water, and has a boiling point 70 Separation of water. After the reaction period of from about 75 to 200 C. the ester may be steam distilled to remove un 7. The method of preparing a fenchyl ester of reacted borneol, giving a 97% yield of ester. The a dicarboxylic acid including heating, at a tem 75 latter may be distilled under reduced pressure perature above 100 C., fenchyl alcohol with the acid in the presence of a solvent for the 75 4 2011,707 reactants which is non-reactive in the process, anhydride with borneol until a substantial amount immiscible with water, and has a boiling point of an acid ester is obtained, then adding a lower of from about 75 C. to 200 C. aliphatic saturated monohydric alcohol and Con - 8. The method of preparing a bornyl ester of tinuing the heating, the reaction being carried Out phthalic acid including heating, at a tempera in the presence of a solvent for the reactants, ture above 100° C., borneol with phthalic anhy which is non-reactive in the process, immiscible dride in the presence of a solvent for the re with water, and has a boiling point of from about 75° C. to 200° C. actants which is non-reactive in the process, 15. The method of preparing a mixed ester of . immiscible with water, and has a boiling point a dicarboxylic acid including heating, at a tem O 0 of from about 75 C. to 200 C. 9. The method of preparing a fenchyl ester of perature above 100° C., a secondary terpene al phthalic acid including heating, at a tempera cohol with the acid until a substantial amount of an acid ester is obtained, then adding a lower ture above 100°C., fenchyl alcohol with phthalic aliphatic saturated monohydric alcohol and Con anhydride in the presence of a solvent for the tinuing the heating, the reaction being carried 5 reactants which is, non-reactive in the process, out in the presence of a solvent for the reactants, immiscible with water, and has a boiling point of which is non-reactive in the process, immiscible from about 75° C. to 200° C. - with water, and has a boiling point of from about 10. The method of preparing a mixed ester 75° C. to 200° C. of a dicarboxylic acid by direct esterification 20 20 including heating, at a temperature above 100 16. The method of preparing a terpene ester C., with the acid a mixture of two alcohols, one . of a dicarboxylic acid including heating, at a of which is a secondary terpene alcohol and temperature above 100° C., a secondary terpene the second of which is a lower aliphatic satu alcohol with maleic acid in the presence of a Solvent for the reactants which is non-reactive in rated monohydric alcohol, the reaction being the process, immiscible with water and has a boil 25 25 carried out in the presence of a solvent for the ing point from about 75° C. to 200° C. reactants, which is non-reactive in the process, 17. The method of preparing a bornyl ester of immiscible with water, and has a boiling point of a dicarboxylic acid including heating, at a tem from about 75° C. to 200 C. perature above 100° C., borneol with maleic acid 11. The method of preparing a mixed ester of 30 30 phthalic acid including heating, at a tempera in tha presence of a solvent for the reactants ture above 100 C., phthalic anhydride with two which is non-reactive in the process, in miscible alcohols one of which is a secondary terpene al With water and has a boiling point from about cohol and the second of which is a lower ali 5° C. to 200° C. 18. The method of preparing a mixed ester of phatic saturated monohydric alcohol, the reac 35. 35 tion being carried out in the presence of a solvent a dicarboxylic acid by direét esterification in for the reactants which is non-reactive in the cluding heating, at a temperature above 100° C., process, immiscible with water, and has a boiling a secondary terpene alcohol with the acid in the point of from about 75 C. to 200° C. presence of butanol. - 12. The method of preparing a mixed ester of 19. The method of preparing a mixed ester of phthalic acid including heating, at a temperature . a dicarboxylic acid by direct esterification in 40. - 40 above 100° C., phthalic anhydride with fenchyl cluding heating, at a temperature above 100° C. alcohol until a substantial amount of an acid borneol with the acid in the presence of butanol. ester is obtained, then adding a lower aliphatic 20. The method of preparing a mixed ester of saturated monohydric alcohol and continuing the a dicarboxylic acid by direct esterification in heating, the reaction being carried out in the cluding heating, at a temperature above 100° C., 45 45 presence of a solvent for the reactants which is fenchyl alcohol with the acid in the presence of non-reactive in the process, immiscible with wa butanol. ter and has a boiling point of from about 75 C. 21. The method of preparing a mixed ester of to 200° C. . , a dicarboxylic acid by direct esterification in 13. The method of preparing a mixed ester of cluding heating, at a temperature above 100 C. 50 50 phthalic acid including heating, at a temperature fenchyl alcohol with phthalic anhydride in the above 100° C., phthalic anhydride with a second presence of butanol. ary terpene alcohol until a substantial amount 22. The method of preparing a mixed ester of of an acid ester is obtained, then adding a lower a dicarboxylic acid by direct esterification, in aliphatic saturated monohydric alcohol and cons cluding heating, at a temperature above 100° C., 55 55 tinuing the heating, the reaction being carried a secondary terpene alcohol with phthalic an out in the presence of a solvent for the reactants hydride in the presence of butano. which is non-reactive in the process, immiscible 23. The method of preparing a mixed ester of with water, and has a boiling point of from about a dicarboxylic acid by direct esterification in 60 75°.C. to 200° C. cluding heating, at a temperature above 100° C., so 14. The method of preparing a mixed ester of secondary terpene alcohol with maleic acid in phthalic acid by direct esterification including the presence of butanol. heating, at a temperature above iO0 C., phthalic JOSEPH. N. BORGIN.