I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
May 1950
903
half of t h e p l a s t i c i z e r c o n t e n t . T h e results confirm the laboratory data presented above.
30
25
,
Flame out Time
CONCLUSIONS
eo Flame out l5
Time in 8ecs.
IO '1
I
\
SEE TABLE VI1
I
XCIP
\
0
0
KDOP 50
10 40
Figure 6.
5
\
3
I
I
20
30
40
30
20
IO
Effect of Chloroparaffin Content
plant tests of extruded vinyl tape have been under severe conditions in which chloroparaffins constituted one
The. problem of stabilizing vinyl plastics containing chloroparafis was reinvestigated in the light of recent advances in stabilizer technology. Vinyl plastics products of excellent quality were obtained through the use of a recently developed basic lead salt, dibasic lead phosphite, particularly when used in conjunction with dibasic lead stearate lubricant-stabilizer. The effective stabilization of chloroparaffin containing vinyl plastiw gave products of excellent eleotrical characteristics and heat and light stability with improved economy and flame resistance.
RECEIVEDOctober 27, 1949. Presented before the Division of Paint, Varnish, and Plastios Chemistry at the 116th Meeting of the AMERICAN CHEMICAL SOCIETY, Atlantic City, N. J.
Trirnethylbenzyl Chlorides and Their Derivatives PREPARATION FROM AROMATIC PETROLEUM STOCKS HOWARD D. HARTOUGH Research and Development Department, Socony- Vacuum Laboratories, Paulsboro,
Chloromethylation of aromatic petroleum stocks to produce polyalkylbenzyl chlorides has been found to be a practical method for preparing reactive chemical intermediates from petroleum stocks containing mixtures of paraffins, naphthenes, and polyalkylbenzenes. The isolation of trimethylbenzyl chlorides from aromatic stocks containing trimethylbenzenes is described as an example of this work. Reaction variables have been studied. Separation and identification of the isomeric trimethylbenzyl chlorides are discussed. A study of preparation of numerous chemical derivatives has been carried out, )c
I T H the advent of catalytic cracking in the petroleum industry and the accelerated cracking program brought about by World War 11, aromatic petroleum stocks were made available in which the aromatic hydrocarbons were the major components. The process for separating the xylenes and trimethylbenzenes from their respective petroleum fractions in pure form a t that time was not so clear-cut or so economical as was desired. A study was undertaken, therefore, to determine means of preparing useful chemical derivatives of these aromatic compounds in the presence of the paraffinic and naphthenic components. One of the best methods was found to be the conversion of the more reactive aromatic hydrocarbons to the corresponding polyalkylbenzyl chlorides by chloromomethylation. This involved the introduction of -CH2C1 into the aromatic nucleus by means of formaldehyde and hydrochloric acid. In this
N. J .
manner the xylenes could be converted to dimethylbenzyl chlorides and the trimethylbenzenes to the trimethylbenzyl chlorides. The latter were of sufficient reactivity to undergo a second chloromethylation, as is shown by the following equation :
For the greater portion of the work a petroleum stock containing 60 to 70% of aromatic hydrocarbons boiling in the range of the trimethylbenzenes (150' to 185' C.) was chosen. Even this narrow fraction contained small amounts of xylene and ethylmethylbenzenes, although it was substantially free of tetramethylbenzenes. The major components of this cut were pseudocumene (1,2,4trimethylbenzene), I, and mesitylene (1,3,5-trimethylbenzene),11. The ratio of I and I1 present in this stock was about 4 to 1. The rate of reaction of methylbenzenes with formaldehyde and hy.drochloric acid has been shown by Vavon, Bolle, and Calin (6) to be dependent on the number of methyl groups present and upon their positions on the aromatic nucleus. Using benzene for comparison, the respective rates are listed in Table I. From these rates of reaction it is predictable that when an excess of trimethylbenzenes over the formaldehyde was used in the reaction mixture the resultant trimethylbenzyl chlorides would be a mixture of chloromethylated pseudocumene and mesitylene. This was essentially true, although other compc-
Vol. 42, No. 5
INDUSTRIAL AND ENGINEERING CHEMISTRY
904
CUT NUMBER
Figure 1.
Vacuum Fractioria tion of 'rrimethylbenzj-l Chlorides
nents were found to be present on close fractionation (Figure 1\ The proof of structure of component A and component B was carried out as follows:
CHI I
- >
CH&I I
I
--+
cH3-0-cH3 -
2,4,6-Triniethylbenzyl chloi,ide from mesitylene
Oxidation
CHs Isodurene COO11 I
'/ CK
2,4,6-Trimethylbenzoic acid
CHzCI I
REICIIO\
ExroHs
Becaube prior wail; in this field as summarized by Fuson ant1 McKeever ( 1 ) indicated that the temperature of 60" to 70" C and the concentrations of the aqueous 36% formaldehyde and the concentrated commercial hydrochloric acid employed, as aell as their respective reaction molar ratios (1 to 3), were optimum, these factors mere held constant in order to studr othei variables. The variables of the reaction mere considered to be the molal ratio of the formaldehyde to the aromatic hydrocarbon, the time of reaction, the stirring, and the effect of gaseou. hydiogeii chloride which had been used by all previous workers. The aromatic petroleum stock contained approximately 607, of aromatic hydrocarbons, xhich n-ere predominantly trimethylbenzenes. The calculation of molecular quantities, therefore, was made on this basis. Because the dichloromethylation to produce 1- and other similar isomeis rTas considered undesirable, attempti: were made to control it to a niiiiimum or, in other molds, to coiivert a maximum amount of the formaldehyde to the monochloiomethylated product. Table I1 shows the effect of varying the molar ratio of formaldehyde. The effect of time as a variable of this reaction had not previously been reported in the literature. Inasmuch as the amount of dichloromethylation was a factor easily determined to within a few per cent, hourly samples were taken up to the &hour leaction time recommended in the literature. A 50-gram sample was taken, diluted n-ith 50 grams of petroleum ether, and stored
I
CHI
TABLE I. RELATIVE RATESO F CHI,ORO\IEIHYLATIOS BEKZESEHOMOLOGS
IV
Benzene Toluene &Xylene
2,4,S-Trimethylbenzyl chloride from pseudocumene
OF
1 3 (i
m-Xylene p-Xylene Pseudocume~ie hlesitylene Prehnitene
CHI 2,4,5-Trimethylbenzoic acid The reaction is complicated somewhat by the fact that I11 is chloromethylated the second time to produce 1,3-di-(chloromethyl)-2,4,6trimethylbenzene,V, melting point 102-103' C. The rate of this reaction appears to be somewhat below the initial rate of chloromethylation of pseudocumene but not so far below as to prevent partial conversion of I11 to V beforc formation of IV. V has been observed in every chloromethylation.
2-1 2 46 600 850
TABLE 11. EFFECT OF MOLAR RATIOSos YIELD Mole Ratio of Aromatics to Formaldehyde 1
1.5 3 a
Based on formaldehyde.
-
Yielda, % Trimethylbenzyl Dichloromethylated chlorides product 41 41
33 30
75
17
I N D U S T R I A L AND E N G I N E E R I N G CHEMISTRY
May 1950
in a cold room at -25' C. for 24 hours. The crystalline dichloromethylation products were filtered off, freed of petroleum ether, and weighed. The results are presented in Table 111. Thus, it is indicated that the greater portion of the monochloromethylation took place during the first hour and the reaction proceeded thereafter a t the expense of the monochloromethylated products. Perhaps the most pronounced of the variable factors waB the stirring. Because the process is necessarily a two-phase reaction, it progressed chiefly through intimate dispersion of the aqueous and organic layers, In the laboratory, yields as high as g5% were consistently obtained Rrhen the stirring was carried out by means of a hollow T-type stirrer and a Signal motor rated a t 1500 r*P.m*Without load. In a 3O-gallon dass-lined P f a u d h kettle an anchor-type stirrer rated a t 80 rep.m. failed to give yields higher than 10% of theory. This factor was overcome by the use of a baffle-type stirrer rated a t 140 r a m . Yields in this apparatus averagedabout 75% throughout the investigation. Because gaseous hydrogen chloride was the most expensive chemical used, its omission would considerably diminish the cost of the reaction. In a series of five runs using 3 moles of aromatics and 2 moles of formaldehyde the average yield was 77%. A similar set of experiments using gaseous hydrogen chloride as a booster for the aqueous hydrochloric acid gave yields averaging 83%. It was later found that by employing molecular ratios of 3 moles of aromatics to 1 mole of formaldehyde instead of a 3 to 2 ratio, consistent yields of 95% could be attained without use of gaseous hydrogen chloride as a booster.
TABLE111. EFFECT OF TIMEON YIELD OF MONO-AND DICHLOROMETHYLATED PRODUCT^ Yield of
100
:
80
z
ro
0
60
cn
50
0 W
2
a9
2
:
1 2 3 46
52.5 70 75 77.5 85
None 6.5 10.7 14 5 16,6d
TABLEIV. SUMMARY OF SEMIPILOT PLANT CHLOROMETHYLATION O F TRIYETHYLBENZENE STOCK" %
Run No.
Aromatic Stock, CH20, Lb. Lb.
1 2 3 4 5 6 7 8 9 10 11 12
97 90 91 45 90 91 00 .. '
90 93 53 70 70
20 20 20 37 17.5 16.5 17.5 17.5 17.5 16 14 14
200 BB. HC1 Lb.' 70 70 70 135 70 70 70 90 46 72 75 75
CDHU, CHz0, Moles Moles
220 204 207 113 204 207 204 204 211 120 159 159
112 112 112 228 98 93 98 98 98 90 78 78
HC1, Moles
318 318 18 635 818 318 318 408 209 327 341 341
Yield Based CsOb
79 75. 77' 4O1 68' 65 72 72 52 90 73 87 c
%action temperature 70' C. for 8 hours. b Yield based on both mono- and dichloro-methylated product-i.e on amount of -CHeCl introduced into stock from given amount of CHzO:' Reaction time, 16 hours. a
highest yields obtainkd based on the formaldehyde, the proportion of dichloromethylated product was considered excessive. In view of this factor, the charge shown in run 11 was preferred and was used in a majority of cases. The efficient stirring required for this reaction was attained with a conventional Pfaudler 140 r.p.m. baffled stirrer. The reaction mixture was maintained a t 65 to 70" C. for 6 to 8 hours until the specific gravity of the finished product became nearly constant. Figure 2 shows the yield based on formaldehyde versus the time for run 3 of Table IV. The ratio of trimethylbenz 1 chlorides to the dichloromethylated products in the 3O-galyon Pfaudler kettle was found to be higher than that obtained in the laboratory. For example, in run 3, 20.6 pounds of trimethylbenzyl chlorides and 2.1 pounds of dichloromethylated product were obtained and 75.5 pounds of unreacted charge stock were recovered.
Specific gravity of charge stock at 22.2 C., 0.828 Specific gravity of pure trimethylbenzyl chlorides, 1.040 Specific gravity of crude reaction mixture at 22.2' C., determined Gain in weight due to introduction of --CH,CI, 48.5 Molecular weight of trimethylbenzenes, 120 O
40
30
The actual gain in weight was determined by the change in specific gravity multiplied by the charge in pounds and a constant.
20 IO
0
methylated Dichloroproduotc, %
CALCULATION OF YIELDS. In an effort to check yields hourly and to save the effort of weighing the reaction product, a semiempirical formula was set up whereby yields could be calculated directly from specific gravity readings taken with a hydrometer. The following factors were used in the calculations:
90
V
Hours
Total Yield, % *
a 3:1 mole ratio of aromatic hydrooarbon t o formaldehyde b Yield calcd. by weight gained in aromatic layer assuming gain in weight of 48.5 grams equivalent to introduction on 1 mole of -CH*Cl group. Yield based on moles of formaldehyde employed. cRecryatallization of product from petroleum ether incoated i t was 1 3di-(chloromethyl)-2,4,6-trimethylbenzene, m.p 101-102 C. Liquid hiohloromethyl isomers noted in subse uent chloromethylations have been shown to be absent in early stages of c%loromethylation. d Distillation of remaining sample substantiated yield figure given.
CH LOROMETHY LATIOS PROCEDURE
LABORATORY PROCEDURE. To 1000 grams of a petroleum stock, boiling point 150" to 185" C., containing approximatel 70 * 1% of aromatic hydrocarbons (about 6 moles of trimethy? benzenes), were added 165 grams (2 moles) of 36% formaldeh de and 800 ml. of concentrated hydrochloric acid (36%). $he mixture was vigorously stirred with a hollow T-ty e stirrer. A Signal motor rated a t 1500 r.p.m. was found sugcient for the stirring. After being heated a t 70" C. for 6 hours, the mixture was cooled and transferred to a separating funnel, and the organic layer was separated and weighed. A gain in weight of 96 grams was equivalent to 99% yield. After water washing, the organic layer was dried over a small amount of calcium chloride and distilled in vacuo. Two hundred and sixty grams (76%) of trimethylbenzyl chlorides, boiling point 120" to 150" C. a t 14 mm., were received as distillate and 40 grams (18%) of dichloromethylated product were obtained as a residue. SEhiIPILoT PROCEDURE. A glass-lined 3O-gallon Pfaudler kettle was charged with a trimethylbenzene fraction (60% aromatics), the, concentrated hydrochloric acid, and the formaldehyde as shown in Table IV. \T7hile run 10 represents the
905
2
4. 6 HOURS
8
10
Figure 2. Percentage Yield of Monochloromethylated Hydrocarbon
%yield =
(increase in sp. gr.) (charge in lb.) (constant) (100) (1) theoretical gain in weight
The value of the constant is 2 and can be derived from the following:
INDUSTRIAL A N D ENGINEERING CHEMISTRY
906
Constant =
(100) (48.5) (100) (120) (1.040 0.828) 48.5
-
25.4-
or approximately 2 (2)
This formula and constant have been used consistently with excellent results. For example, in run 3 the gain in weight obtained by weighing the reaction mixture was 9.3 pounds, which represents a 75% yield. The calculated gain in weight using the above formula was 9.36 pounds. INVESTIGATION O F COMPONENTS OF TRIMETHYLBENZYL CHLORIDES
Four liters of current production trimethylbenzyl chlorides were subjected to vacuum fractionation a t a pressure of 2 mm. of mercury through a column packed with glass helices equivalent to 8 to 10 theoretical plates. Seventy-seven and one-half cuts of 50 ml. each were taken, each cut representing 1.25% of the total. Figure 1 summarizes the data with boiling and refractive index curves. The boiling points are calculated to a standard pressure of 760 mm. using a conventional nomograph. The dotted lines in the figure indicate results obtained on refractionation of the intermediate cuts. The following experiments were run on cuts 5 to 11 to establish the structure of component A and on cuts 30 to 41 to establish the structure of component B.
OXIDATION.To 150 ml. of water containing 91 grams of lead
J
nitrate were added 51 grams of the trimethylbenzyl chloride and the mixture was heated a t 100' to 105' C. for 6 hours. Evolution of nitric oxide was noticed throughout the refluxing period. Upon cooling, the crystalline material was filtered by suction and digested with petroleum ether. The white solid was digested with absolute alcohol to separate the trimethylbenzoic acid from the lead chloride. Usually about 12 grams of crude acid were obtained. This was purified by dissolving in sodium carbonate solution, boiling with decolorizing charcoal, precipitating by acidulation, and finally recrystallizing from aqueous alcohol. Extraction of the petroleum ether. with 10% sodium hydroxide solution produced a deep red aqueous solution which upon acidulation gave a semisolid reddish precipitate that decomposed slowly in water to become completely solid. About 20 grams more of the trimethylbenzoic acid can be accounted for if a benzyl nitrate is formed that slowly decomposes and oxidizes t o the trimethylbenzoic acid. About 20 grams of a light red oil giving characteristic aldehyde tests were obtained on evaporation of the petroleum ether. Cut 7 of component A gave a mixture of trimethylbenzoic acids, melting point 150-151.5' C. Cut 32 of compone:t B gave 2,4,5-trimethylbenzoic acid, melting point 150-151 C. [literature ( 3 ) lists melting point of 148-149" for the 2,4,5- acid and melting point of 151 for the 2,4,6- acid]. REDUCTION.Fifty-two grams of the pure trimethylbenzyl chloride were mixed with 50 ml. of benzene, 100 ml. of water, and 5.0 ml. of concentrated hydrochloric acid. To this well stirred mixture were added 38 grams of zinc dust (93%) over a period of 2 hours in 1- to %gram portions. The temperature was controlled between 30' and 42' C. during this addition. After this period, 50 ml. more of acid were added and the mixture was heated at the reflux temperature for 4 hours. The mixture was cooled, the benzene layer drawn off, and the product distilled from a Claisen flask. Cut 7 gave a mixture of durene and isodurene but redistilled out 9, ny 1.5378, gave pure isodurene, boiling point 195-200" C., 1.5109 (literature value is 1.5104). Cut 33 gave pure durene (38 grams), melting point 79" to SO" C. (literature value is 79.3" C.). Cut 58, boiling point 287" C., n Y 1.5430, gave no definiteo compound on reduction. The mixture, boiling point 206 to 210" C., nY 1.5138, dig 0.891, suggests the compounds are ethyltrimethylbenzenes. O
PROPERTIES AND DERIVATIVES OF TRIMETHYLBENZY L CHLORIDES
These materials are stable to light and heat on storage. They are only slightly lachrymatory and have slight vesicant action on tender skin between fingers or on the face. They are extremely sensitive to metal contaminants and decompose rapidly
Vol. 42, No. 5
when warmed in their presence and are best distilled over a little solid potassium carbonate to deactivate any dissolved metals. Distillations have all been carried out in glass and no alloyed steel5 have been found that are totally satisfactory. Teflon packing of joints is recommended over lead-lined asbestos or neoprene. The ti~imcthylbenzyl chlorides me more reactive chemically than benzyl chloride and enter mc+athetical reactions vigorously and in most cases quantitatively. In the case of semipilot plant operations it was found convenient to use the crude chloromethylated mixture, because the unreacted material acted as a diluent and helped dissipate the heat from exothermic reactions. Distillation or purification was therefore generally carried out on the finished product. These preparations are summarized in Table V. Laboratory small scale runs were usually made on the pure trimethylbenzyl chlorides and convenient solvents were used whenever necessary. Although not all the laboratory preparations listed were carried out in semipilot plant scale equipment, many of the preparations listed appear to be ready for larger scale operation without obtaining further laboratory data. With the exception of the ethers listed in Table VI1 and the esters listed in Table VIII, these data are summarized in Table VI along with a brief description of the process and the resultant products. IYVESTIG4TION OF COMPONENTS OF TRIMETHYLBENZY L ALCOHOLS
The alcohols as prepared in the laboratory slowly crystallize. Dilution of the mixed alcohols with petroleum ether, followed by chilling, yields a crystalline portion representing about 65% of the total alcohols. Two recrystallizations from petroleum ether yield a mixture of alcohols, melting point 58 to 64". Subsequent recrystallization fails to improve the melting point. The only satisfactory method of separation involves dissolving 8 grams of the alcohols in 1200 ml. of hot water and fractionally
TABLEV. DERIVATIVESO F TRIYETHYLBENZYL CHLORInRwj PREPARED ON A SEMIPILOT PLANT SCALE Wt. of Charge Stock, .4lcohols
Derivative
Method and Reactants Hydrolysis with rvater and excesb Ca(0H)s:
Amines
20115' gal. ofC.CHIOH for 7 hours satd.
Lb. 92"
Yield, Lh. (Monohydric) 25 (Dihydric)O 1
IO.0 Primary amine 3.75 Secondary amine 3,28 with S H I (17 lb.) a t 25' C.; room temp. Tertiary amine 2 for 32 hours Total 8.24 Ethanolamines 27 lb. of ethanolamine: 21 e 2 hours a t room temp ' 4 hours at 60-706 C.d Ethyl ethers 9 7 . 8 Q 29 25 lb. ethyl alcohol: 8 lb. of KaOH in 8 Ib. of water. 126136' C. for 4 hoursf a Charge stock contained 70 t o 78 gram moles of trimethylbenzyl ohlorides. h Obtained as residue by steam distillation of filtered reaction mihture. These alcohols cannot be distilled in conventional petroleum stills, and decompose rapidly, presumably because of sulfur in tar deposits. Szperl (4) describes decomposition of benzyl alcohol i n presence of trace amounts of sulfur. These alcohols are best distilled in glass. An alternative procedure for purification involves formation of the CaC12 complex: Equal parts of crude alcohol, benzene, and anhydrous calcium chloride are agitated together for 24 hours at 25'. The benzene layer is drawn off and calcium chloride slurry is washed three times with benzene. The complex is decomposed, wjth water and the alcohol is extracted with benzene. After steam stripping of benzene, alcohols are of good purity and compare favorably with materials prepared i n laboratory. Filtered lime cake was dried and extracted with dioxane to extract the 1,3-di-(hydroxymethyl)-2,4,6-trimethylbenzene. After three recrystallizations this product melts a t 188-189' C. [literature ( 2 ) lists m.p. of 188-
,.
1ono1lo>
d Excess ethanolamine and ethanolamine hydrochloride separated off at end of reaction a8 insoluble bottom layer. e Product obtained as residual bro.wn viscous oil containing 6.1% nitrngen (theory, 7.3% nitrogen) and no chlorine. An attempt to distill (his material led to material of b.p. 194-208' C. a t 6-mm. pressure. Decomposition set i n a t 205-210° C. and distillation was discontinued. f Carried out in 50-gallon Dopp autoclave under about 100 lb./sq. inch.
c
INDUSTRIAL AND ENGINEERING CHEMISTRY
May 1950
~
OF (CH3)&a*0R ETHERS TABLE VII. PREPARATION
TABLEVI. DERIVATIVESOB TRIMETHYLBENZYL CHLORIDES PREPARED ON LABORATORY SCALE
Derivative Alcohols hrnines (tertiary) Amines (tertiary)
Method and Reactants 206 g. of CaO in 1500 ml. of water: reflux 4 hours 1 liter of CHsOH, stream of N&. gas: 50" for 1 hour 1 kg. of coml. ammonium hydroxide: 24 hours a t room temperature and .then a t loOD 25.8 g of n C4He)zNH in 70 ml. o! water and 16.8 g. of NazCOa NaSH (1:l mole) in 500 ml. of abs. alcohol; reflux 1 hour From mercaptan and 36%.CH10 in preaence of trace of HC1 From sodium mercrqptide and &B'-dichlorodiethyl ether
Trirnethylbenzyl Chlorides, G. 500
Yield, Wt. % Based on Chlorides Charged 78'3
503
100
337
100
N.iV-Dibutyl-2,4,30d 100' 5-trimethylbenzyl amine 169 2.4.5-Trimethvl80/ benzyl mereaptan .... 91.5 Di-(2.4.5-trimethylbenzy1)thioformalo 8,,4'-Di- (2,4,5-tri65h .... methyl benzylthio) diethyl ether .... lOOi Sodium trimethyl- From sodium trimethylbenzyl mercaptide5 and benzyltrithiooarbonate csz 169 87i Di-(trimethylSodium trimethylbenzylbenzyl)-trithiotrithio carbonate, 1 carbonate mole 1OOk 0 . 6 3 mole of NazSz in 300 140 Di-(trimethylml. of water: reflux 4 ( 0 . 8 2 mole) benzyl) -disulfidesi hours 72mbn 0 - andp-Trimethyl185 179 g. of phenol in 400 benzylphenols ml. of xylene; reflux 6 hours 2.4-Di-(trimethyl94 g. of phenol in 400 ml. 337 LOO benzyl)-phenolso of xylene; reflux 6 hours * These isomeric alcohols boiled a t 144-164O C. a t 1 2 mm.; n"n" 1.5403, d;:': 1.0100. b I n addition, 78 g. bf di-(trimethylbenzyl) ethers, b.p. 260-270O C. at 20 rnm., d?!.: 1.0028 obtained. Anal. Calcd. for CzoHzaO; C, 85.1: H, 9.3. Found:*"C: 85.1; H, 9.2. C Heated t o 100' to remove excess ammonia. d Pure 2 4 5-trimethylbenzyl chloride. e Pure &duct boils a t 156' C. a t 7 mm.; n"n" 1.4912. Anal. Calcd. for ClsHalN. N 6 36. Found: N. 5.34 f Product'biils a t 137-138O C. at' 14 mm. Anal. Calcd. for C i o H d : 5. 19.27. Found: 8 , 19.10. Product has pleasant odor and is noncorrosive t o copper a t 150° C. h Anal. Calcd for CzaHs4OSa' 9 15 9 Found: €3, 17.5. i Reddish power melting a b i v e 205; C. Anal. Calod. for CIIHiaStNa; 5, 36.4. Found: 9, 36.6. f Anal. Calcd. for CziHzsSs: 5, 25.7. Found: S, 25.8. t The product is light yellow oil of pleasant odor. Anal. Calcd. for CzoH~aSt: 5, 19.33. Found: S.18.35. 1 Di-(trimethylbenayl) trisulfides and tetrasulfides are prepared from dieulfides by addition of calcd. amount of sulfur when heated at 130-135" for 6 hours in presence of 1 g. of tri-n-butylamine for each 10 g. of sulfur. . These materials have been shown t o be good cutting oil additives. Product is light yellow, b.p. 200-225° C. a t 10 mm. phenols obI n addition, 50 g. of viscous yellow 2,4-di-(trimethylbenzyl) tained. Anal. Calcd. for CzaHaoO: hydroxyl No. 159. Found: hydroxyl No., 169. 0 If prepared without aid of xylene solvent, product is more resinous and more difficult to diasolve in lubricating oils. More resinous roducts are usually more effective stabilizers for petroleum hydrocarbons tgan products obtained using xylene solvent. Similar type products have been prepared from n - , m-, and p-cresols, catechol, resorcinol, hydroquinone, pyrogallol and I-naphthol
recrystallizing. The first portion, melting point 8684.5 ', was proved to be 2,4,5-trimethylbenzyl alcohol by oxidation to 2,4,5-trimethylbenzoic acid, melting point 150-151 '. The second alcohol, melting point 91-92 ', oxidized to a benzoic acid, melting point 134-135". Because such physical constants of an alkyl benzoic acid are not listed in the literature, the original alcohol was presumed to be an ethyldimethylbenzyl alcohol. No investigation of isomers in the liquid portion was undertaken. TRIMETHYLBENZYL ALKYL ETHERS
These compounds were prepared by the classical Williamson synthesis (Method I) or by a modification that consisted of heating the benzyl chlorides with a mixture of.aqueous or solid sodium hydroxide in the alcohol desired for the etherification (Method 11). The yields in all cases approached the theoretical. Table VI1 summarizes the data obtained in the preparation of various ethers. I
907
~~~
R
Method
Boiling Point, a C. 220-237 228-242 224-249 124-140 132-170 249-270 110-125
Pressure, Mm. 760 760 760 7.5 18
16
e
dD: 0,948O 0.934' 0.924 0.920 0.915
n
aD"
I1 1.5014 Methyl 1.5035 Ethyl I, I1 1.5038 Isopropyl I 1.5000 n-Butvl I 1,4966 I aec-BGtyl I1 t-Butyl (thio ether) 0,927 1 . io27 I1 760 Mixed amylc I ,. .. Cetyld 2-Hydroxyethyl 16 113-139 5 .. -CHz-CH$175-250 I/ 6 .. .. a 23'. Anal. Calcd. for CNHZZS;S, 14.4. Found: 9, 14.0. C From fusel oil. d Waxlike solid, m.p. 30-40' Anal. Calcd. for CzaH410: C, 83.2; H 12.5. Found: C. 82.3: H , 12.0. a 47.5% meld from excess ethylene glycol a n d sodium. I Xylene used as diluent for reaction of ethylene glycol and sodium.
*
,.
TRIMETHY LBENZY L ESTERS
These materials are easily prepared by refluxing the corresponding acid and alcohol in xylene solution to remove the water (Method I ) or by reacting the sodium salt of an acid with the trimethylbenzyl chlorides (Method 11).
TABLE VIII. PREPARATION OF (CH8)8C6H200CR ESTERS RCOOAcetatese Lrtctatesb LauratesC Stearatesc Phthalatesd Phthalatesd
Method I1 I1 I
I
1
I1
Saponification No. Calcd. Found 291 296 135 261 261
170 218 220
' B.p. a t 2 mm. d
115-123', d i 5 ' 1.0251, n%O 1.5137. Decomposed on heating to brown, brittle, thermoplastic resin Brown semisolid product. Tan viscous liquid.
UICHLOROMETHY LATEL) THIMETHY LBEN ZEN ES AN W DERIVATIVES
ISOLATION OF 1,3-DI-(CHLOROMETHYlr)-2,4,6-TRIMETHYLBMNV, FROM CHLOROMETHYLATION BOTTOMS. The semisolid to solid bottoms obtained from the distillation of the trimethylbenzyl chlorides were melted and transferred to an ap aratus suitable for distilling crystalline material. The materia? boiled at 160' to 180' at 14 mm. and cr stallized upon cooling. The melt was recrystallized from petroium ether and the pure product melted a t 102-103" [literature (8) lists melting pyint of 105"j. Evaporation of the petroleum ether mother liquor elded liquid isomers of dichloromethylated trimethylbenzenes t r a t were not further identified. The usual ratio of solid to liquid isomer was about 4 to 1. CHLOROMETHYLATION OF TRIMETEYLBENZYL GHLORIDES. One mole of trimethylbenzyl chlorides was treated with 1.2 moles of formaldehyde as trioxymethylene and 8 moles of concentratedl hydrochloric acid. The mixture was stirred a t 60" to 70" for 24 hours. The gain in weight was 29 grams indicating a 60%) yield (see prior discussion on calculation of yields). Distillation, yielded unreacted trimethylbeneyl shlorides and liquid and solidi isomers of the dichloromethylated trimethylbenzenes, boiling point 130' to 163' at 6-mm. pressure. These were not investigated further. Formalin solution, instead of trioxymethylene, gave a 48y0 yield of dichloromethylated product. Zinc chloride failed to give an increased yield (490J0)when used in the presence of t h e formalin solution. 1,3- D I - (METHOXYMETHYL) - 2,4,6- TRIMETHIYLBENZENE. This compound was prepared by warming V with methanol containing excess sodium hydroxide. Single crystals of this compound weighing 10 grams and measuring nearly an inch in width can be grown from slow evaporation of a petroleum ether solution, melting point 63-69 , Quick crystallization yields crystals melting point 68-69" [literature (9) lists melting point of 67.568.5 '1. The corresponding ethyl ether was prepared in the same manner, but could not be made to crystallize and was not purified further. ZENE,
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
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TABLE IX. DI-BCII, ESTEROF V (CH,),C,H--(CH,OOCR)l R-COODiacetate Adipate Azelate Dilaurate Maleate Phthalate Sebacate Distearate
Description Cryjtalline Flexible, nontacks light yellox- resin Flexible, elastomeric light yellow resin Tan, amorphous solid Light yellow. brittle. thermosetting resin Light red, brittle resin Tan, amorphous solid Waxy solid, n1.p. 40°
DIESTERS OF V. These compounds were prepared in the same manner as the monoesters described previouslp. T H I O K O b T Y P E RESIN FROM A N D SODIUM P O L Y q iJLFIDES. These products were light yellow to white pliable, elastomeric, puttvlike materials that vere ext’remely insoluble in all common solvents. RESINFROM STYRENE AYJ) 11. This product a s s prepared by react,ing equimolar quantWes of styrene and V ivith a trace of zinc dust at’ about 100”. The resulting resin was good ctrlo~ed, soft, and pliable.
Vol 42, No. 5
moles of ammonium thiocyanate in 50% ethyl alcohol was added 1 mole of v and the mixture it‘as heated at reflux for 2 hours, Theoproduct, yhen recrystallized from alcohol, melted at 109111 . Analysis. Calculated for C,jHiaN,S,: S, 24.5. Found:
s, 26.2.
ACKNOWLEDGMENT
The author is grateful to 0. RI.Reiff and D. E. Badertscher for their advice and interest in this problem and to A . I. Kosak, C. F. Feasley, and P. I
