Phenol-Modif ied lndene-
Coumarone
of the polymerization to a marked degree. Whereas in the straight polymerization of unsaturates of the indene type even the lowest resinous polymers show no solubility in alcohol, the resins obtained by using phenols as modifying agents proved soluble in alcohol. A later attempt (2) to react jointly a mixture of indene or indene derivatives with phenols made use of hydrochloric acid or metal chlorides as the catalyst. The products obtained ranged from viscous oils to resins. The resins were marked by solubility in alcohol. The viscous oils were found to consist of alkali-soluble and alkali-insoluble constituents. The alkali-soluble constituents were reported as corresponding probably to the general formula !!
Resins
H
JOSEPH RIVKIN AND W. E. SHEEHAN The Neville Company, Pittsburgh, Pa.
T
HE production of resins and oils from crude solvent naphthas derived from coke-oven light oils has received considerable study both from the manufacturing and theoretical viewpoints. The reactive constituents of the crude solvent naphthas are principally indene and coumarone and, to a varying extent, dicyclopentadiene :
112
where R represents an aromatic nucleus substituted by a t least one hydroxyl group. The alkali-insoluble constituents of the viscous oils were reported to represent condensation products probably containing ether bondages. Further work along this line involved the use as catalysts of ferric chloride and of borofluoro fatty acids (3). In all cases where unsaturates of the indene type are subjected to conditions inducing polymerization, both oily and resinous polymers are formed, the proportions of the two depending on the catalyst employed and other conditions of reaction. It was the view of one of the present authors that within a wide range of catalysts that might be employed, the products of the mixed reaction involving unsaturates of the indene type and a phenol were of similar type, if the reaction was carried out under suitable conditions and proportioning of reactives.
Results of Earlier Procedures
INDEIUE
. .
COUMARONE
D I CYCLOPShTADI ENE
Practically all of the work in this field has been concerned with the straight polymerization of these compounds into resinous and oily polymers. A considerable number of catalysts have been found effective in carrying out the polymerization reaction, but of these only sulfuric acid has been of commercial significance to date. The coumarone resins as produced commercially are mixtures of polymers of the polymerizable constituents of the crude solvent naphthas. The hard grades, which are of greatest commercial significance, show good though varying solubilities in aromatic and aliphatic solvents, such as the coal-tar light41 solvents and petroleum naphthas, and no solubility in alcohols.
Modified Indene-Coumarone Resins Relatively few attempts have been made to modify the properties of the resins and oils resulting from the polymerization of unsaturates of the indene type by introducing into the reaction substances other than these unsaturates. The use of phenols as modifying agents has received some attention. The earliest reported results (4) covered work with sulfuric and sulfonic acids as catalysts. The results established definitely that, by introducing a phenol as a reactive along with the indene and indene-type unsaturates in crude solvent naphtha, it was possible to modify the course
Reactions carried out according to the procedure of the earliest reported work (4) using sulfuric and sulfonic acids as catalyst proved that hard resinous as well as viscous oily products were produced, as was expected. Reactions carried out according to the procedure of the subsequently reported work (2) using hydrochloric acid as catalyst also yielded both viscous oily and resinous products. The ratio of resin to oil in the former case was much greater than in the latter, in which the bulk of the yield consisted of viscous oil. This is an illustration of the general influence of the type of catalyst, among other things, on the proportion of oily to resinous products. The resins from both reactions were similar in properties. The viscous oils from both reactions were also similar in properties. The resins in both cases were marked by solubility in alcohol. The viscous oils in both cases were marked by a solvent action, when heated, on cellulose acetate.
Use of New Catalyst The work with which the present article is concerned had as its purpose the production of phenol-modified resinous polymerization products by carrying out a mixed reaction involving crude solvent naphtha and commercial .phenols. The principal point of departure in the work reported in the present article from earlier work along this line was the use of a new catalyst. This new ca sesses a number of advantages f tions involving phenols and unsaturates of the indene type. As indicated by a study of prior work on the subject, the presence of a phenol with indene when subjected to the action 1228
NOVEMBER, 1938
INDUSTRIAL AND ENGINEERING CHEMISTRY
of a polymerization catalyst could result in the phenol entering the reaction, with consequent marked changes in the properties of both the hard resinous products and the viscous oily products. This indicated that the phenol was capable of entering the reaction a t any of the stages of polymerization, including the monomer stage. It was further noted that the extent to which the phenol entered the reaction depended, among other things, on the vigor of the catalyst used and on the conditions of the reaction. Vigorous polymerization catalysts or reaction conditions promoting vigorous polymerization favor the straight polymerization of the indene and indene-type unsaturates a t the expense of the mixed reaction involving the phenol; there is a possibility, under certain conditions, that the rate of straight polymerization is so high in comparison with the rate of mixed reaction that the proportion of mixed reaction products is negligible and the properties of the resulting products are substantially the same as if no phenol were present during the reaction. It was therefore essential to reduce to a minimum or to eliminate totally the tendency toward straight polymerization of the indene and the indene-type unsaturates and to set up conditions favoring the mixed reaction involving the phenols. A number of ways for attaining this result were worked out later in the laboratory. But initially i t was necessary to start with a catalyst that could be used to obtain a slow polymerization rate and the effectiveness of which for obtaining polymerization could be varied by varying conditions. Activated clay was found to answer this need and showed the additional advantage of eliminating the problem of corrosion which the use of an acid catalyst would involve, as well as of eliminating the need for a neutralization step which would be necessary with the use of an acid catalyst.
Reaction Factors and Products
1229
It should be stated that because of their physical properties the viscous oily products really fall in the classification of soft resins and are perhaps better and more appropriately described as such than as oils. As already mentioned, the difference in the properties of both the hard resins and of the viscous oils from the properties of the corresponding hard resins and viscous oils produced in the straight polymerization of unsaturates of the indene type indicated that the phenols had reacted with the unsaturates a t various stages of their polymerization, from the monomer on through the various polymers. The Bradley and Gibbs tests (1) applied to the hard resin and to the viscous oily products showed the presence of constituents of phenolic structure in both. A check on whether or not water was liberated during the reaction as a result of condensation showed that substantially no such water was liberated. This precluded the possibility that condensation reactions might occur of the type resulting in structures from which their oxygen content has been eliminated in the form of water as a result of condensation. Since structures of the above type are purely hydrocarbon in nature, they would explain neither the alcohol solubility nor the solvency for cellulose acetate of the reaction products. These specific properties of the reaction products, plus the fact that they showed alkali absorption, plus the proved presence of Constituents of phenolic structure in them, indicated that the reactions taking place were of the following type : H
a.
H
B
H
The optimum temperature range for carrying out the reaction with activated clay as catalyst was found to be between 90" and 110" C . The effect of varying the ratio of phenol to indene and indene-type unsaturates was also investigated. The results may be summarized as follows: 1. Increasing the proportion of phenols favors the improved alcohol solubility of the resulting reaction products. 2. Increasing the proportion of phenols results in an increase in the roportion of viscous oily reaction products. 3. &creasing the proportion of phenols results in a lowering of the melting point as well as of the molecular weight of the hard resinous reaction products.
The proportions of phenols and crude solvent naphtha finally selected as standard for production purposes were those yielding the optimum melting point and solubility in alcohol of the hard resin. A follow-through of a laboratory procedure productive of satisfactory results under this general technic is as follows: The reactants were 400 cc. of crude @vent naphtha and .lo0 cc. of commercial cres3-h acid. The catalyst consisted of 30 gram-s of activated c!ay. The reaci%nts and catalyst are brought together and maintained a t a temperature range of 85" to &L5xLunder vigorous agitation and conditions p r o v m r reaction temperature control. At the end of 4 hours the reaction is substantially complete. The reaction mass is then filtered and the filtrate is distilled. The nonreactives of the crude solvent naphtha and any unreacted phenols and unsaturates are collected first as a forerunnings cut. The viscous oily condensation produots are collected next as a steam and vacuum distillate. The hard resin remains behind as the distillation residue.
H
E.
Reactions of this type do not involve the evolution of water; they explain the ability of the reaction products to take up alkali, explain the phenolic reaction of the reaction products, are in agreement with the conclusions of prior work, and are
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"
+
--5.
ECBC-C\-CIH
'c=cA H
H
VOL. 30, NO 11
H2
H H
E.
H
I\
properties of the hard resinous and viscous oily products obtained by the straight polymerization of indene-type un-
H H
H
\J Ii
i!
jC/ Fg
nonextractable products of the phenol-modified polymerization differ from the products of straight polymerization in that the former yield hard resins which are soluble in isopropanol and viscous oily products which are soluble in metha-
NOVEMBER, 1938
INDUSTRIAL AND ENGINEERING CHEMISTRY
-
This structure is indicated in a study of the course of the reaction by the following facts:
OF Two HARD RESINS TABLE11. PROPERTIES
Values Detd. on Hard Resins c -
M .p.. Resin 1
85
wt. 403
92
440
a
2
C.
. Mol.
Mol. Wt. of No. of Theomol. of retical unsatuCompn. rate 340 2 354 2 372 2 386 2 456 470 504 518
3 3 3 3
Theoretical Composition Kind of unsaturate Indene Indene Dicyclopentadiene Dicyclopentadiene Indene Indene Dicyclopentadiene Dicyclopentadiene
No. of mol. of phenol 1 1 1 1
1 1 1 1
-__ Fractions of
wta .. n,ta --"-.
nn
--
Viscous Oily Mol. Wt. of No. of Reaction Theoretical mol. of Products Compn. unsaturate 1 217 224 1 222 238 1 245 240 260 254 1
Theoretical Composition No. of Kind of mol. of unsaturate phenol Indene 1 Indene 1 Dicyclopentadiene 1 1 Dicyclopentadiene
7
Kind of phenol Cresol Xylenol Cresol Xylenol Cresol Xylenol Cresol Xylenol
TABLE I1 I. MOLECULAR WEIGHTSAND THEORETICAL COMPOSITION OF VISCOUSOILYREACTION PRODUCTS Range of N[ol.
1231
7
Kind of phenol Cresol Xylenol Cresol Xylenol
1. From a certain point in the reaction the proportion of the viscous oily reaction products to the hard resinous reaction products begins to decrease. The viscous oily reaction products, as has been shown, are essentially the result of the reaction of one molecule of indene, coumarone, or dicyclopentadienc with one molecule of a phenol. 2. The unreacted unsaturates decrease in proportion through the entire course of the reaction, but the free phenols decrease to a certain point, after which they begin to increase slightly, especially at higher temperatures of reaction.
Figure 1 shows these trends graphically. The advantages of using activated clay as the catalyst for carrying out phenol-modified polymerization of unsaturates of the indene type have already been mentioned. The flow diagram in Figure 2 indicates the simplicity of this method. The diagram in Figure 3 shows one type of plant equipment that can be used for carrying out the reaction.
Properties of Resins Molecular weight determinations indicate that in the hard resins of good alcohol solubility the polymers combined with -the phenol molecule are largely dimers and trimers, the reaction taking place according to B and C in the two preceding groups of formulas. (As a reacting unit dicyclopentadiene is viewed as a monomer analogous to indene and coumarone for the sake of simplicity, although in reality it is a dimer.) Table I1 gives the melting points and molecular weights of two hard resins of good alcohol solubility as well as the theoretical molecular weights of the dimer-phenol reaction products and the trimer-phenol reaction products. The molecular weights of indene and coumarone are so nearly similar (116 JC\ and 118, respectively) that, considering experimental error, indene in Table I1 may be taken to represent coumarone as far as molecular weights are concerned. The phenol used in the work 3R described in the present article was ri commercial cresol containing both cresols and xylenols. An examination of Table I1 indicates that the hard resins produced by the reaction are largely mixturesof the reaction productsof thedimer and the trimer with cresol and xylenol. Molecular weight determinations also indicate that the viscous oily or soft resinous reaction products are largely the result of the reaction of one molecule of indene, coumarone, or dicyclopentadiene with one molecule of a phenol, the reaction taking place according to A in OR the two preceding groups of Eormulas. Y Table 111 gives the range of molecular weights determined on fractions of the viscous oily products as well as the theoretical molecular weights of the products resulting from the reaction of one molecule each of indene, coumarone, and dicyclopentadiene with one molecule of a phenol. A study of the general course of the reattion points to a lateral reaction of -the type indicated at the right.
The properties of the resins resulting from phenol-modified polymerization of unsaturates of the indene type are markedly different from the properties of the resins resulting from the straight, unmodified polymerization of these unsaturates. One broad mark of differentiation already mentioned is that the latter are insoluble in alcohols whereas the former are soluble. The phenol-modified indene-type resins differ further from the regular indene-type resins in the matter of compatibility with other materials, a circumstance which makes these phenol-modified indene-type resins of special interest in the
ri
+
H
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FIGURE 2. FLOW DIAGRAM OF PHENOI~MODIFIED POLYMERIZATION OF UNSATURATES OF T H D ~ N D E N ETYPE
coatings, adhesives, and plastics fields and in other applications. Table IV shows the difference in the compatibilities of some materials with phenol-modified indene type resins and with unmodified indene-type resins. In the specific application in oleoresinous varnishes, the phenol-modified indene-type resins vary from the straight indene-type resins in their effect on tung oil. Tung oil varnish films sometimes exhibit an undesirable tendency to “gas check” when dried under certain atmospheric conditions, such as combustion fumes. This gas checking is evidenced by a frosting, crystallizing, or checking of the film. In tung oil varnishes employing straight unmodified indenetype resins, especially in varnishes long in oil, this gas-check-
WGfR
BY-PAJJ TRAP
I
FIGURE 3. TYPEOF PLANT EQUIPMENT FOR THE REACTION
ing tendency can be overcome only by substitution of part of the indene-type resins by such resins as rosin or the varnishtype phenol-aldehyde resins and by using large proportions of lead compounds such as litharge. Phenol-modified indenetype resins, on the other hand, yield varnishes which do not TABLEIV. DIFFERENCE IN COMPATIBILITY OF MATEIRIALS gas check, without the necessity of substituting part of the resin by other resins or of using excessive quantities of lithWITH Two TYPES OF RESINS arge. By employing in combination straight unmodified Phenol-Modified Unmodified indene-type resin and phenol-modified indene-type resin, Indene-Type Indene-Type Material Resinm Resin’ highly gas-resistant tung oil varnishes can be prepared without the use of rosin or of the more costly phenol-aldehyde Plasticizers: Bodied castor oil Comp. Incomp. resins or of excessive quantities of litharge, and by considerAcetylated castor oil Comp. Incomp. ably easier cooking manipulation. Methyl ester of polymerized Unlike the straight indene-type resins, the phenol-modified ricinoleic acids Comp. Part. indene-type resins find a definite place in the formulation of Ricinoleic acid Comp. Incomp. nitrocellulose lacquers. The softer grades, such as those of Natural resins: 65-70’ C. melting point or even lower, have been found esPart. Incomp. Congo gum pecially useful. The ratio of the resin to nitrocellulose should Comp. Incomp. Kauri gum be maintained a t or below one part of resin to two parts of Manila gum Comp. Incomp. nitrocellulose. Lacquers so formulated exhibit remarkable Synthetic resins: pliability together with excellent hardness and adhesion. Alkyds, oil-modified Comp. Part., incomp. Alkyds, phenol-modified Phenol-aldehyde, unmodified, varnish type, Methacrylate Vinylite Miscellaneous : Cellulose acetate Nitrocellulose
Comp.
Part.
Comp. Comp. Comp.
Part., comp. Part. Incomp., part.
Part. Comp. in certain proportions Comp. Incomp. Comp.
Incomp.
Incomp. Part. Comp. Comp. (better than phenolmodified resin) Vistanex Part. Incomp. Comp. = compatible; part. = partially compatible; incomp. = incompatible. Ethylcellulose Pliolite Tornesit
Literature Cited (1) Bradley, T. F., IND.ENG.CHEM., Anal. Ed., 3, 304 (1931); Gibbs, H.D., J. Biol, Chem., 72, 649 (1927). (2) I. G. Farbenindustrie A.-G., U. S. Patent 1,764,052 (April 8, 1930); British Patent 297,075 (Sept. 14, 1928). (3) I. G. Farbenindustrie A.-G., U. S. Patenta 1,857,333(May 10, 1932); 1,863,814(June 21, 1932); 1,863,881(June 21, 1932). (4) Rutgerswerke A,-G., German Patent 302,643 (1919). RECEIVH~D May 7 , 1938.
