US2411113A - Treatment of polyene compounds - Google Patents

Description

.PatentedNov. 1946 Y I l v UNITED STATES PATENT OFFIJE TREATMENT OF POLYENE COMPOUNDS Anderson W. Ralston, Chicago, and Otto Turinsky, Palatine, 111., assignors to Armour and Company, Chicago, 11]., a corporation of Illinois No Drawing. Application January 22, 1942, Serial N0. 427,834

6 Claims. (o1. 2s0 o5.6)

This invention relates to processes of treating change can be materially reduced by the use of polyene organic compounds and it more specifi-' high boiling organic solvents and strong alkalies. .cally relates to the treatment'of unconjugated Other investigators have found that the alkali polyene organic material, such asfats and fatty process may be improved by conductingthe reacacids having a plurality of double bonds with 5 tion in'aqueous solution at elevated temperatures inorganic iodides of elements of the third, fourth and pressures. However, any such process which and fifth groups of the periodic table of elements, employs alkali has inherent disadvantages. In

whereby the unconjugated polyene materials are order to conduct this process it is necessary that converted to conjugated polyene products or to the fats or fatty acids be converted -to soaps.

, products having mp ved drying or resinifying These soaps must'then' be acidified in orderto qualities. Y obtain the transformed fatty acids. Where one It has hitherto been recognized that the desires to conjugate an oil a number of steps are. chemical properties of unsaturated organic comtherefore, necessary in orderto produce desired pounds having a plurality of double bonds depend results by these processes. It is necessary to first not only upon the degree of unsaturation but also 16 sappnify the fat and then to treat the soaps with upon the relative position of the unsaturated strong caustic in order to bring about conjugabonds with respect to each other. If the un-. tion, acidify the resulting soaps, purify the fatty saturated bonds are conjugated then the organic acids and finally r'eesterify them withglycerine. compound has properties characteristic of un- It would be extremely desirable. to develop a saturated compounds, and in addition, has those 20 process whereby the unconjugated fatty acids or.

ystems.- 1 sity of saponification or other chemical change.

The distinction between conjugated and un- Such a process would be much easier to-conduct conjugated systems is well illustrated by compar- On a commercial scale and would have :a number ing the chemical behavior of linolenic acid and of apparent advantages over the alkali processes eleostearic acid. These acids are isomeric, for bringing about this transformation. Even chemical properties characteristic of conjugated fats could be treated directly without the necesstraight chain fatty acids each containing three before the introduction of the alkali methods double bonds. It is believed that inlinolenic acid various investigators have sought to find comthe double bonds are in the 9-10, 12-13 and pounds which would produce the'desired isomeri- 15-16 position while in eleostearic acid they zation directly. For example, the Schrieber occupy the 9-10, 11--12 and 13-14 positions. Patent No. 1,896,467 lists a number of compounds Thus in eleostearic acid the double bonds are conincluding sulfuric acid, ferrous iodide, chlorine, jugated. When linseed oil is used as a paint oxygen, etc., for this'purpose; but none: of these vehicle the paint dries quite differently than it compounds have proved effective or havecome would if eleostearic acid were used. Eleostearic into commercial use.

acid is the chief fatty acid constituent present We have-now discovered a class of compounds in tung oil glycerides. Tung oil body-dries which catalytically improve to a very marked whereas linseed oil film-dries." Body-drying is degree the drying or resinifying properties of much preferred and is believed to result from unconjugated systems. This improvement inthe fact that eleostearic acid is conjugated. 40 valves a change of the unconjugated unsaturated Therefore, it is highly desirable that ways be system to a conjugatedunsaturated system but' developed by means of which unconiugated we cannot definitely state that all the improvehighly unsaturated'compounds can be converted ment in drying properties is explained bythis njugated, unsaturated compounds and thus transformation.v The substances which weuse ain the advantages inherent in conjugated to bring about this transformation are used in systems.

relatively small amounts at elevated temperatures The fact that the relative position of double which shows that they function as truecatalysts.

bonds in an alkyl chain-can be changed 'byrtreat- The class of compounds we use can be generally ment with strong alkalies has been known for described as inorganic iodides of elements of the 4 some time. In Biochem. J. 31, 138 (1937') Moore third, fourth and fifth. groups of th periodic:

reported thattreatment offats and fatty acids table of elements. Such iodides include iodides with alcoholic potassium hydroxide brings about of phosphorus; tin, aluminum, antimony, and

a shift in the relative position of double bonds in arsenic, these being representative elements of an alkyl group and that this shift is towards a. the third, fourth and fifth groups which form conjugated configuration. ,Recently Kass and 56 iodides. Iodides of aluminum have been found Burr, J. Am. Chem. Soc. 61, 3292' (1939; have particularly desirable incur improved process. shown that thethnenecessaryto bring about this In practicing our process the unconiugated substance to be treated is admixed with small amounts of one or more of said iodides and then ment. Other oils, such as cottonseed oil, peanut oil, corn oil and other oils not ordinarily regarded as drying oils, can also be treated by this procedure and their drying characteristics substantially improved. Instead of treating the oils directly, we can hydrolyze the oils to obtain the natural mixtures of fatty acids and then subject the mixture to the treatment for producing conjugation. pared may suitably be reacted with a polyhydric alcohol and a dibasic acid to form alkyd resins, or may be re-esterified with glycerol or the higher alcohols such as pentaerythritol or dlpentaerythritol to form synthetic glycerides having improved drying characteristics.

Particularly in connection with the oils which are not normally classed as drying oils, such as cottonseed 011, corn oil, peanut oil, soyabean oil, etc., we find that especially good results can be obtained by first subjecting the acid mixture obs -tained from such an oil to fractional distillation and then subjecting a relatively low boiling volatile fraction so obtained and containing a higher The conjugated mixtures thus preproportion of the polyene acids, to the catalytic treatment described above.

Another procedure includes first subjecting the acids obtained through hydrolysis of natural oils to solvent extraction whereby there is produced a portion which contains unsaturated acids in greater proportion than in the original acid mixture, and then subjecting this portion to catalytic treatment as before described or, additional benefits may be obtained by first fractionally distilling the acid mixture, treating the fraction so obtained by solvent extraction, and then catalytically treating the resulting product using the herein disclosed inorganic iodides as the catalyst.

Though our improved process finds its greatest advantage in connection with those oils or natural mixtures of fatty acids which are classed as unconjugated oils or acids, the process can also be used to advantage in connection with oils and acids normally classed as conjugated but containing appreciable amounts of unconjugated compounds. Dehydrated castor-oil is one of 7 those products normally considered conjugated,

but it does contain amounts of unccnjugated compounds'and it is markedly improved by the catalytic treatment described herein. a

We shall now give examples of specific ways I of practicing our process.

Example 1 A stream of nitrogen gas was,

heating and cooling period, as presently described,

'to serve as a means of agitation and to supply an inert atmosphere. The mixture was heated to 255 C. and one part by weight of phosphorous iodide added. The temperature was held between 255 C. and 260 C. throughout the remainder of I the heating period. Two more portions of 0.5

' part by weight each of phosphorous iodide were- The iodine value dropped from 135 to during treatment and the diene value increased from an initial value of 2 to a final value of 34.3. These values indicate that appreciable conjugation has been brought about by means of this treatment.

Example 2 Sixteen parts by weight of linoleic acid which contained approximately 35% of oleic acid and 0.016 part by weight of stannic iodide were mixed together. A stream of nitrogen gas was passed over the surfaceof the mixture both during the heating and cooling period. The test tube and its contents were heated in an air bath. After three minutes the temperature was 200 C. The heating was discontinued after 15 minutes. the temperature havingattained a value of 345 C. The refractive index'of the original fatty acid mixture was n2o=1.4672 and the refractive index after treatment was 1l2o=1.4733. The iodine value of the original fatty acid mixture was 144 which dropped to 117 after treatment. The diene value of the original mixture was 2 and attained a value of 24.3 as a result of the treatment. These values indicate that appreciable conjugation has been brought about by means of this treatment.

Example 3 Three-hundred and thirty-nine parts by weigh of refined soybean oil was weighed into' a reaction vessel. The vessel was equipped with a motor stirrer to give eflicient agitation. A stream of nitrogen gas was passed over the surface both during the heating and cooling period. The mixture was continuously stirred and heated to'a temperature of 265 C. Phosphorous iodide was then added in approximately 0.1 part by weight quantities throughout the heating-period. The total heating time in the presence of the catalyst was 2 hours and 20 minutes. The temperature was allowed to increase gradually to 300 C. The total :amount of phosphorous iodide added was 2.2 parts by weight. The refractive index of the original oil was nzo=1.4'753 which remained constant until the phosphorous iodide was added.- The refractive index after treatment was nzo=1.4797. The iodine value dropped from 133 to 109 during treatment and the-diene value increased from an initial value of 1.5 to a final value of 10.0. When spread on glass the above treated oil dried giving a film which appeared frosted, a characteristic of those oils in which there occur unsaturated conjugated systems. These data indicate that appreciable conjugation has been brought about by means of this treatment. a

' Example 4 Three-hundred and seventeen parts by weight by weight of aluminum triiodide was added. The

total heating time was 42 minutes, and the temperature ranged during this period from 260' C. to 270 C. The addition of the catalyst brought about a rapid rise in refractive index, and the heating was discontinued when the rate increase of refractive index was markedly lower. After 42 minutes, heating was discontinued and the fatty acids cooled rapidly.

, The following data shows changes resulting from this treatment:

Before After treatment treatment Refractive index (me) 1.4668 1.4734. Iodine value 145 101. Dione value 1.5.- 26.6.

Action with stannic chloride Veryslight.. Gelled.

These results indicate that appreciable conjugation has been brought about by this treatment.

Example Three-hundred and seventeen parts by weight of the linoleic-oleic acidmixture described in the precedingexample was heated to 260 C. with continuous stirring in an atmosphere of nitrogen. The catalyst in this case was antimony trilodide which was added in three portions, that is, 0.1 part by weight was added when the temperaof the refractive index was lower. When the heating was discontinued, the fatty acids were rapidly cooled inan atmosphere of nitrogen. The following analytical data shows 7 that appreciable conjugation has been brought about by this procedure.

Before After treatment treatment efractive index (up) 1.4068 1.4m. odine value-.- 146 1N1. Dione value 1 1.5- 21.2. Action with stannic chloride. 8

Example a Fourteen-hundred parts by weight of extracted soy bean oilwere treated'with ,a catalyst which .was prepared as follows:'- Eight parts by weight ofiodine and 7- parts by weight ofaluminum turnings were mixed with parts byweight of carbon disulflde and the mixture refluxed for about 20 minutes. After this time the color ofthe iodine had completely'disappeared indicat ing the formation of aluminum triiodide. Since an excess of aluminum wasjemployed, the .re-

mainder was unreacted and was present as metallic aluminum. The catalytic mixture wasthen added to the soy been .011 and this mixturewas then heated to 170 under an atmosphere of nitrogen andwith sumcient stirring until the refractive index of. the oil showed no further inutes. There was a. marked increase intherefractive index of the oil at the time the item perature reached a value of 130 C. It required an additional 20 minutes heating time to raise ture attained 260 C., an additional 0.2 partby weight was added 20 minutes later, and a final 0.1 part by weight was addedminutes after the first addition. The reaction temperature varied from 260 C. to 270 C. The addition of the'catalyst brought about rapid rise in refrac- 'tive index, and the heating was discontinued when this rate of rise in refractive index was markedly lower. The total'heating time in this case was minutes, after which time the fatty acids were rapidly cooled in an atmosphere of nitrogen.

The following examination of the sample before treatment and after treatment show that appreciable conjugation has been brought about by, this process.

Before After treatment treatment Refractive index (mo) 1.4729. Iodine value 14 117. Diene value .5 14.6. Action with stannic chloride Slight Gelled.

El'rample 6 Three-hundred and two parts by weight of the linoleic-oleic' acid mixture described in the preceding example was heatedto 260 C. with continuous stirring under an atmosphere of nitrogen. When the temperature attained 260 C., 0.2 part by weight of arsenic. triiodide was added and the heating continued for 35 minutes, after which time 0.03 part by weight of arsenic triiodide was added. The total heating time under these conditions was 40 minutes and the temperature varied from 260 C. to 270 C. The heating was discontinued when the rate of rise 1 5 Drying behavior the temperature to 170 C., and the mixture was then heated for an additional 20 minutes at this temperature.- After this heating period, the reaction mixture was cooled under an atmosphere of nitrogen. The constants of the .oil before and after treatment were as'follows: I

Before treatment After treatment Refractive index (on) 1.4836. Iodine value. 101.6. Diene value 0 Slightl tac :froeted iilm imhgurs. Reaction of stannic Immediate rubbery chloride. gel.

hours. Non-ge1ling These analytical corfstants and observations show that appreciable conjugation has been brought about in this soy bean oil by this treatment.

Example 8 The catalyst employed was aluminum triiodide which was prepared in a manner similar to that described under the previous example; The only difference in the catalyst used in this example and in the previous example was that 16 parts 'byweight of iodine wereemployed in stead of 8- parts by weight as in the former example. The catalyst mixture was added'to 1400 parts by weight of raw linseed oil and the heating was conducted as described in the foregoing example. The oil showed a marked increase in refractive index when the temperature reached C. It required 52- minutes to heat the oil to C. and the refractive index became constant 36 minutes laterwith the temperature rising slowly to (2. jThe reaction mixture was then cooled under anatmosphere of nitrogen This required a total time of 48 mm.

the initial andthe. starting'materials.

is wasteful and serves no useful purpose.

and the following analytical constants recorded:

The catalyst was prepared by shaking; to-

gether 1.2 parts by weight of iodine, 1' part by weight of phosphorus and 10 parts by weight of carbon disulflde. This .was added to 195 parts by weight of extracted soy bean oil and the mixture was heated in an atmosphere of nitrogen with sufllcient stirring. At the end of minutes the temperature rose to 150 at which time the refractive index of the oil showed appreciable increase. The temperature was permitted to rise slowly and after an additional 68 minutes,

it had reached 178 C. at which time the refractive index showed no further increase. The reaction mixture was then cooled in an atmosphere of nitrogen. The following analytical constants and observations were obtained upon Before treatment After treatment Refractive index (n t). 1.4811. j Iodine value l 102. Diane value 1.6 1&0. Drying behavior. h Dry after 70 hours.

' Reaction with stannic Non-gelling".-. Rubbery gel in 5 min.

chloride. I

These analytical constants and observationsshow that the oil has been appreciably conjugated by this treatment.

In all instances the fatty acids which have been catalytically treated in the above described processes, can be esterifled to form esters, and can be used in the arts wherever the'use of conjugated unsaturated fatty acid esters is desirable.

dioxide, as we have found that this practice yields aproduct of a desired character having improved color and drying characteristics. However, our invention may be practiced without this feature.

We can operate at various times and temper-I.

atures. One of the characteristics of our invention is that conjugation is imparted quite rapidly, and this is a. definite commercial advantage. Our oils and fatty acids can be heatedfor longer periods of time, if, for example, it is desired to impart bodied characteristics to the-oil rather than conclude the heat treatment after conjugation alone has been imparted to the oil or fatty I acid., That is to say, conjugated, unsaturated fatty acids and glycerides thicken when heated I for somewhat longer periods of time than we have In the foregoing examples wherein iodine and phosphorus or aluminum. or other element of the third, fourth and fifth groups are brought together and the resulting product added to the oil or fatty acid, it is desirable to have a slight excess of the metal element present. However, as the foregoing examples show, an excess of the metal is not essential.

The oil or other polyene compound, after treatment in accordance with our process, neednot'be separatedfrom the catalyst for most uses; to which the treated oil.is to be put. However, the catalyst can be separated from the treated material by the application of conventional caustic refining processes.

The amount of catalyst required is small. The Q amounts given in the foregoing examples have beenfound to give good results but still lesser quantities maybe employed. More than the quantities stated can, of course, be used but this If desired the catalyst may be removed from the 'final oil by any of the usual refining methods,

an inert atmosphere such as nitrogen or carbon indicated in our examples.. Therefore, we can,

of course, impart conjugation to the unsaturated compound during a relatively short period and continue the heating for a longer period of time, up to two or three hours, if we wish to body the oil or fatty acid. Such thickened oils have much higher viscosity than the simple conjugated fluid oils, and this may be the result of polymerization of the conjugated material present.

Therefore, we do not wish our invention to be limited to any particular time of heating. Those skilled in the art will understand different oils may'require different heating periods and that the oil or fatty acid is to be heated until appreciable improvement in diene value issecured and that heat is to be discontinued before this product is bodied more than is desired.

Similar considerations apply with respect to temperature.

tures can be used but with a relatively slower reaction rate. For example, we can operate at temperatures below C. and under certain conditions this. has been found to be advan- I tageous.v Obviously, the temperature should not exceed the volatllization temperature of the material-undergoing treatment, nor should it be so I high as to decompose the oil or fatty acid. But

within these operative limits suitable temperatures can be chosen.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. The process of conjugating a polyene compound chosen f-rom the group consisting of unconjugated polyene fats and fatty acids which comprises heating said polyene compound in the presence of an inorganic iodide chosen from the group consisting of iodides of elements of the third, fourth and fifth groups of the periodic j system, and discontinuing said heating after substantial conjugation of said polyene compound has been effected, but before the thus conjugated polyene compound becomes substantially heat bodied.

2. The process as in claim 1 wherein the iodide is phosphorous iodide.

3. The'process as in claim 1 wherein the iodide is aluminum iodide.

compound is soy bean oil.

5. The process as in claim 1 wherein the polyene compound is linseed oil.

compound is heated o'rro ronmsxr.

At the temperature stated con- .jugation is imparted rapidly. Lower. tempera- 4. The process as in claim 1 wherein the polyene ANDERSON w. rtA1sTon.' q