INDUSTRIAL AND ENGINEERING CHEMISTRY
January 1953
193
'
TABLE V. COMPARISON RUNSBETWEEN OLEUMAND SULFURIC ACID Total Time, Hr.
Temp., Run
69 75 56 77 61 76
C. 100 100 HIO off R~Ooff HnOoff H1Ooff
I
0
Y
(Mole ratio of reactants, 1 t o 1; time of acid addition, l/t hour) Wt. % Wt. % Yield, % (Toluene-Free Basis) Excess TolueneAcid Wt. % TolueneSulfuric sulfonic Concn., Toluene sulfonic Sulfuric Unacoounted Acid Acid % Recovered acid acid Water for
Agent Acid Oleum Acid Oleum Acid Oleum
2 2 1 1 2 2
38.13 23.76 34 19 19.66 22.79 9.00
62.05 76.89 68.62 79.10 80.58 90.80
72.37 67.87 72.82 68.65 69.19 59 64
32.5 17.5 13.13 15.0 9.35 6.25
I
t q-
WAZER REMOVED
TUE O f ADDITION
\
- 0.6 HR.
RATIO 1'1
\
'O
100
I I20
I 140 TEMPERATURE
I 160
-
I
iao
I
200 DEOREE GENTIORADE
I
4 I
220
Figure 9. Effect of Varying Final Reaction Temperature during Sulfonation on Conversion to Toluenesulfonic Acid
after refluxing has ceased is given in Table IV and shown in Figure 9. The 96% sulfuric acid was added to the toluene in ¶/$-hour and the reaction run up to the final reaction temperature with refluxing and constant heat input, a t which time the reaction temperature was held constant for 1/2 hour by controlling the heat input. The results show that 91% conversion could be obtained a t 150" C. At temperatures over 150' C. the reaction mass turned black and increasing quantities of insoluble materials were formed. Finally at 225' C. the reaction mass began to decompose shortly after the temperature had been reached, with both water and toluene being given off. At the higher temperatures the
63.57 77.29 65.87 80.66 77.73 89.64
22.81 13.69 18.88 11.49 12.65 5.09
8.71 6 48 7.05 5.25 5 63 3 45
4.81 2.54 8.20 2.60 4.I9 1.82
Para Isomer, Y O
83.2 79.0 82.3 78.3 84.6 78.2
final sulfuric acid concentration was found to increase to 92%. Also, the per cent para isomer decreased as the temperature was increased and in the section on caustic fusion the increase was largely the meta isomer. Based upon the yields obtained it waa found that the maximum yields are obtained a t temperatures below 150' C. OLEUM VERSUS 96% SULFURICACID. Several runs were carried out in which 15% oleum was added to the toluene over a period of 1/2 hour. The results of these runs compared to the results obtained with 96% sulfuric acid are given in Table V. The use of oleum improved the yields from 12 to 15% but the yield of para isomer decreased about 6% where oleum was used. The final sulfuric acid concentration where oleum was used as the sulfonating agent was comparable to the results from the use of 96% sulfuric acid where the yields of toluenesulfonic acid were the same. Subsequent work showed that the material from the oleum runs frothed during the caustic fusion step and as a result the over-all yield of cresol was reduced. SUMMARY
Based upon the data obtained it was found that the best results were produced where 96% sulfuric acid was added t o the toluene in the shortest possible time while still being able to control the reaction and where the water of reaction was removed with excess toluene. These results were enhanced where the final reaction temperature was held below 150' C. I n this manner yields of 92 to 95% toluenesulfonic acid can be obtained containing about 84% p-toluenesulfonic acid. Low reaction temperatures increased the yield of meta-ortho isomers as did reaction temperatures over 150' C. The over-all yield of these isomers was never over 25%. The use of oleum increases the yield of meta-ortho isomer to about 22% but frothing occurs during the fusion step.
(Synthesis of Cresol)
CAUSTIC FUSION OF TOLUENESULFONIC ACID
T
HE preparation of synthetic cresol from toluene is essentially a two-step operation: ( 1 ) the preparation of a toluenesulfonate and (2) the hydrolysis of the sulfonate t o cresol. After the toluenesulfonic acid had been analyzed it was neutralized with sodium hydroxide until it was just alkaline to phenolphthalein and then evaporated t o facilitate storage until such a time as the fusion step could be carried out: Some difference exists in the literature as to whether or not sodium hydroxide can be used in the caustic fusion of sodium toluenesulfonate. Gilman (12) states that sodium toluenesulfonate cannot be fused with sodium hydroxide and in order to carry out this fusion it is necessary to use a minimum of 28% potassium hydroxide in a mixture with sodium hydroxide. Mares ( 2 1 ) proposed to use a mixture of sodium benzenesulfonate and sodium toluenesulfonate in sodium hydroxide to carry out the
fusion step. On the other hand, Bouvier and Bardin (6) make no mention of any difficulty in using sodium hydroxide in the fusion step. Tyrer (SO)proposed the addition of either sodium or potassium sulfite or sulfate t o act as an antifoaming agent during fusion. Similarly, LeMaistre, Strickland, and Weaver (10)carried out the fusion of sodium toluenesulfonate without difficulty and obtained a yield of 70% cresol. I n the present work the use of sodium hydroxide in the fusion step was investigated and compared with the results obtained using potassium hydroxide. It should be remembered that all samples in the fusion run contained varying amounts of sodium sulfate from the neutralization of the unreacted sulfuric acid in the sulfonation runs. The equipment used for the caustic fusion of sodium toluenesulfonate consisted of an iron fusion pot 3 inches in diameter and
194
INDUSTRIAL AND ENGINEERING CHEMISTRY
'
10 inches high. -4screw cap acted both as guide for the stirrer and as holder for the thermometer well. The stirrer scraped both the bottom and side wall of the fusion pot and was notched so that the thermometer well could be set deep in the fusion mass. The thermometer well was made from a '/rinch pipe with a plug welded in the bottom. The stirrer was run through a l/aO-hp. motor which was controlled by a Variac so that the speed would be just sufficient to keep the fusion mass in motion without spattering.
100
90 -I
B =eo
P
EZlNQ POINT
YELTINO POINT
e I0
70
sAeE
a
FLECK
#Y 2
ER
a
WILLIAMS
I6 0 Y
50
40 30
35
40 TEMPERATURE
Figure 10.
-
DEGREE
45 50 CENTIGRADE
55
Melting and Freezing Point Curves for the System o-Cresol-p-Cresol-Cineole
Heat was supplied through a Nichrome strip ribbon and controlled by a Variac. Glass cloth was used as insulation for the fusion pot. Known amounts of sodium hydroxide were melted in the fusion pot before the addition of the sodium toluenesulfonate. Time of reaction mas taken from the time the entire mass reached the desired operating temperature until the heat was shut off. ANALYTICAL PROCEDURE
Vol. 45, No. 1
for about 1,'s hour and any water settling out was removed. The ether was then evaporated off in an evaporating dish and the crude cresol was ready for distillation. The distilling flask and condenser were kept as small as possible to reduce loss through holdup in the equipment. The forerunnings taken off up to 185 C. were found to consist of ethvl ether, water, and cresol. Redistillation of the cut from 100" to 185" C. added about 1% t o the total cresol yield. The bulk of the cresol was taken in a cut from 185" to 210" C. This cresol cut plus the redistilled cut was weighed and represented the yield of cresol obtained. The residue in the distilling flask was taken as the difference beh-een the weight of the flask plus residue and the tare of the flask. O
Determination of the per cent o-cresol was found by the method of Potter and Williams ( 2 4 ) and Sage and Fleck ( 2 7 ) in which stoichiometric quantities of mixed cresols and cineole are mixed together and the freezing point is determined. The data of Potter and Williams ( 2 4 ) and Sage and Fleck ( 2 7 ) are shown in Figure 10. The following analytical procedure was used to determine the per cent o-cresol present in the mixed cresol samples: A 2-ml. sample of cineole was mixed with 1.4 ml. of cresol and both freezing point and melting point determinations were made. These were repeated several times for each sample. Data for synthetic mixtures are shown in Figure 10. Analysis of mixed cresol samples were made with more than 50% o-cresol in the sam le because samples containing less than 40% o-cresol were founCf t o supercool and difficult to determine the freezing point. A mixture was prepared by adding 0.7 ml. of o-cresol to 0.7 ml. of mixed cresol sample and 2 ml. of cineole. The freezing point and melting point determination was carried out in a large test tube in a water bath. A thermometer calibrated in tenths from 0" t o 100" C. was used to read the temperature of the mixture in the test tube. The results obtained for t h e melting points in the present work approach the values of Potter and Williams (84) while the freezing point d u e s approach the results of Sage and Fleck ( 2 7 ) . I n order to determine if varying small amounts of m-cresol would have any effect on the melting point of mixed cresols in the ortho determination, several samples were prepared and the results indicate that the presence of up to 14% m-cresol has no effect on the melting point, The available analytical procedures for m-cresol are at best approximations and cannot be considered accurate to more than 2%. The method commonly referred to is that of Raschig (66)in which m-trinitro cresol is formed and determined gravimetrically. Sage and Fleck ( g 7 ) presented a complete procedure for cresols in which the m-cresol was determined by formation of a cresolformaldehyde resin in which only the 0- and m-cresol take part. Since the per cent o-cresol can be determined, the per cent mcresol present can be calculated. An attempt was made to use
Analysis was carried out to determine the per cent total cresol formed based upon the theoretical possible yield as well as the per cent 0-,m-, and p-cresol formed. The weight of residue was noted as such but no analysis of this material was carried out. The yield of total cresol was determined by distillation. Marsel (88)and Shreve and Marsel (88) in work on hydrolysis of chlorotoluene determined the yield of cresol by taking a distillation cut from 180' to 220' C. TABLE VI. EFFECT O F VARIATION O F TIMEA S D TEMPERATURE Othmer and Leyes (83) in their (Ratio of 1.eactants, 21/2 to 1) work on phenol determined the yield of phenol b y taking a distillation cut. Since it was Total Yield, Cresol, % necessary to obtain cresol in % Conversion Ortho Meta Para both a dry and fairly pure form 25.2 114 300 22 88.5 20.5 11.3 9.0 79.7 5 2 . 5 22 4 2 . 5 115 320 88. 5 11.3 9.0 79.7 for analysis of the isomers the 82.5 72.0 340 49 52.6 116 85.7 7.5 10.0 best method available was dis49 74.0 65.0 8.5 117 83.5 85.7 360 8.0 36.0 8 1 . 0 3 0 . 0 9 . 0 119 300 80.0 1 1 . 0 46 tillation. T h e following 52.0 44.4 1 82.1 9.0 126 320 86.0 5.0 55 75.0 1 32b 74.3 11.0 156 340 57.1 86.0 3.0 method was used to recover 75.0 62.0 1 81.0 118 360 85.0 10.0 5.0 46 cresol from the fusion mass: 43.0 32.0 34 2 92.3 109 300 82.5 6.6 11.0 ~
~~
2 320 34 92.3 2 92.2 340 47 22 2 88.5 360 3 82.4 300 180 3 74.3 300 32; 3 82.4 320 18 3 92.7 340 71 92.7 3 71 360 a Water off except where otherwise indicated. b 100' C. C Total reflux.
108
The fusion mass was treated with a calculated excess of hydrochloric acid. The waterinsoluble layer was taken up in ethyl ether and the water layer washed three times with ether. The ether and dissolved m a t e r i a l s were allowed t o stand in a separatory funnel
110
112 124 155 125 129 130
66.0 78.5 68.5 41.0 43.1 66.0 75.0 65.0
52.6 63.2 56.3 36.4 32.0 51.2 56.0 45.0
10.0 8.5 11.3 11.3 11.0 10.0 6.8
6.5
6.0
9.0 9.0 8.0 6.0 9.0 17.0
20.0
84.0 82.5 79.7 80.7 83.0 81.0 76.2 73.5
TolGeneeulionic Acid, % 82.1 82.1 84.3 84.3 83.2 84.3 85.3 83.2 83.0 83.0 84.6 82.1 84.6 85.3 84.6 78.0 78.0
INDUSTRIAL AND ENGINEERING CHEMISTRY
January 1953
TABLE VII.
Run
147 133 114 141 143 145 128 134 116 142 144 146 131 135 109 137 139 150 132 136 110 138 140 151 Q
b
Reaction Time, Hr.
Tpp., C.
300 300 300 300 300 300 340 340 340 340 340 340 300 300 300 300 300 300 340 340 340 340 340 340
Mole Ratio of Reactants 1-1
2-1 21/*-1 3-1 4-1 5-1 1-1 2-1 2 1/2-1 3-1
4-1 5-1 1-1 2-1 21/2-1 3-1 4-1 5-1 1-1 2-1 2l / r l 3-1 4-1 5-1
Run 21b 19 22 50 54 56 55 19 49 50 54 56 58 26 34 23b 45 24b 58 26 47 23 b 45 24b
195
EFFECT OF VARIATION OF RATIOOF REACTANTS Sulfonation Data4 Sodium to1uenesulfonate,
%
.
Total Yield,
%
Conversion
10.4 17.6 20.5 22.4 23.0 18.0 11.6 50.5 52.6 52.0 51.3 43.5 11.9 19.2 32.0 31.5 37.6 31.5 8.0 45.6 63.2 54.8 52.3 48.3
Cresol, % Ortho Meta
6.0 9.0
10.0 9.0 11.3 13.0 13.0 13.0 7.5 8.0 7.5 10.0 12.0 13.0 8.5 6.0 6.5 9.5 9.5 8.0 4.0 9.0 8.5 8.5 9.0 8.0
9.0
7.0 8.0 8.0 6.0 9.0 10.0
9.0 9.0 7.0 12.0 12.0 11.0 8.0 9.0 11.0 12.0 10.0 9.0 7.0 9.0 8.0
Para
PToluenesulfonic Acid, %
'84,O 82.0 79.7 80.0 79.0 79.0 86.5 83.0 82.5 81.0 79.0 80.0 79.5 82.0 82.5 82.5 81.5 81.0 86.0 81.0 82.5 84.5 82.0 84.0
84.3 84.0 82.1 83.0 82.5 82.3 84.3 84.0 84.3 83.0 82.5 82.3 83.2 83.7 83.0 83.2 83.7 81.7 83.2 83.7 84.6 83.2 83.7 81.7
Water removed except where otherwise indicated. Total reflux.
this method but it was found unsatisfactory. Therefore a modified procedure of the Raschig method used by Marsel ( $ 9 ) and Shreve and Marsel (28) was followed with satisfactory results. The procedure is as follows: Five grams of m-cresol and five grams of sample are weighed into a 125-ml. beaker. T o this are added 15 ml. of 96% sulfuric acid, The mixture is swirled to mix t h e cresol and acid and then placed in an oven at 100"C. for 1 hour. After the hour the contents of the beaker are transferred to a 1-liter beaker and chilled. T o the chilled mixture are added 90 ml. of 63% nitric acid. The large beaker is swirled a few times and the contents are allowed t o react with the evolution of nitrogen dioxide. After about 20 minutes 80 ml. of cold water are added t o the beaker, mixed, and allowed t o stand for 1 hour at room temperature with mixing from time t o time. The contents of the beaker are filtered through a tared crucible and the beaker is washed with 100 ml. of water. The Gooch crucible is dried in an oven at 105" C. for 11/2 hours before the crucible is cooled and weighed. The per cent m-cresol is found from the empirical equation
with a sample in which the sulfonation temperature had been 180" C. It will be noted that the meta content is about twice as much as in those runs in which the sulfonation temperature was less than 150' C.
4
mt. m-trinitrocresol X wt. sample X 100 1.74 = m-cresol in original sample)
% m-cresol = ( % m-cresol - 50) X 2
YOL RATIO OF REACTANTS
-
2.511
It was found necessary to extract as much water as possible when filtering in order to dry the samples in the time allowed. As an added precaution a known mixture of 50% m- and 50% o-cresol was run as a blank with every few series of runs.
0
I REACTION TIME
Figure 11.
-
2
3
HOURS
Effect of Time and Temperature of Fusion on Conversion to Cresol
DISCUSSION O F EXPERIMENTAL DATA
VARIATIONOF TIMEAND TEMPERATURE. A series of runs was carried out in which the temperature was varied from 300" to 360" C. and the time of reaction varied from '/a to 3 hours. The results are given in Table VI and shown in Figure 11. I n those runs at 1/2 hour the yield of cresol increased rapidly from 20% at 300" C. to 65% a t 360" C. The weight of residue also increased with increase in temperature. As the reaction temperature was increased an optimum time was reached at each temperature; the time was least a t the highest temperature. Analysis of samples showed'that the para isomer content found by difference between the total cresol and the ortho and meta content was about =k2% of the results obtained for p-toluenesulfonic acid. Experimental error could easily account for this difference, especially since i t was known that analysis of the m-cresol was open to experimental error. Therefore it seems reasonable to state that no significant rearrangement of isomers takes place during the caustic fusion step. At least two runs in this series (Nos. 129 and 130) were made
VARIATIONOF RATIOOF REACTANTS, A series of runs was carried out in which the mole ratio of caustic to sodium toluenesulfonate was varied from 1: 1 to 5 : 1 and the results of this work are given in Table VII. Figure 12 shows that a slight excess of caustic over the stoichiometric quantity required improves the yield. The runs using a 2 1 / 2 to 1 mole ratio of caustic to sodium toluenesulfonate were made with samples containing a low percentage of sodium sulfate. Yields from these samples were slightly higher than from those containing more sodium sulfate. An attempt was made t o correlate the effect of sodium sulfate in the fusion reaction but the results were inconclusive, although the presence of large amounts of sodium sulfate did not seem to be detrimental to the reaction. The ratio of caustic used had no effect on the per cent p-cresol formed and showed only a A270 variation from the per cent p-toluenesulfonic acid in the samples used. PotasSODIUM HYDROXIDE VERSUS POTABSIUM HYDROXIDE. sium hydroxide will react with sodium toluenesulfonate a t a
INDUSTRIAL AND ENGINEERING CHEMISTRY
196
TABLE VIII. Reaction Time, HI.
Run 123 114 122 116 121 109 120 110
Temp., C. 300 300 340 340 300 300 340 340
'/z '/z
'/a
'p2 2 2
COAIPARISOK R U N S USING POTAsSIU&L HYDROXIDE AND SODIUM
Vol. 45, No. I
HYDROXIDE
(Ratio of reactants, 21/2 to 1: all sulfonation runs made with water removed) Sulfonation D a t a Sodium ' Total Fusion tolueneYield , Cresol, % 70 Conversion Ortho Meta Agent Run sulfonate KOH 18 82.4 45.0 53.4 13.0 7.0 SaOH 22 25.2 88.5 20.5 9.0 11.3 KOH 18 82.4 76.5 71.5 13.0 6.0 49 NaOH 85.7 72.0 52.6 10.0 7. 5 KOH 20 64.7 85.0 45.1 7.5 7.0 34 NaOH 92.3 43.0 6.6 32 0 11.0 KOH 20 88.0 64.3 76.0 7.5 9.0 47 NaOH 92.2 9.0 63.2 78.5 8.5
*REACTION
P-
Para 80.0 79.7 81.0 82.5 85.5 82.5 83.5 82.5
Toluenesulfonic Acid, 70 84 6 82 1 84.6 84.3 81.2 83 0 81.2 84 6
Several runs were also carried out with those samples in which oleum had been used as the sulfonating agent. Considerable frothing took place during fusion and as a result the yields of cresol are low. The yield of m-cresol was higher than ahere concetitrated sulfuric acid had been used, apparently a t the expense of the o-cresol. The samples contained as much sodiuni sulfate as many of the samples in which sulfuric acid x a s used for sulfonation so that the presence of or lack of sodium sulfate seemed to have little affect on frothing in this particular case.
TIME
SUMMARY
REACTION TEMPERATURE
I0
I 28 I
I 131
I 381
I 481
- 340'C. I
5, I
J
MOL RATIO OF CAUSTIC TO SODIUM TOLUENE SULFONATE
Figure 12' Effect
Of Varying Ratio Conversion to Cresol
Of
Reactants on
The present work has shown that within the limits of exprrimental error little or no rearrangement of isomers occurs during the fusion of sodium toluenesulfonate. It is also possible t o carry out the fusion step using only sodium hydroxide and the yields obtained a t optimum conditions are comparable to the yields obtained with potassium hydroxide. It was also noted that low sulfonation temperatures favor the formation of ocresol while high temperatures favor the m-cresol. The effect of sulfonation temperature on isomer distribution is shown below: Ortho 7'0 Meta'% Para,'%
25' C. 18-22 4-6 74-76
50' C. 12-18 5-6 78-82
100' C. 11-13 3-6 83-86
Total Reflux 6-12 8-1 1 81-85
Water Removed 6-12 7-12 80-85
lower temperature than sodium hydroxide. At low temperatures comparable yields of cresol can be obtained in shorter time with potassium hydroxide. As the temperature of reaction ECONOMIC BALANCE is increased the yields obtained from sodium hydroxide approach the yields obtained from the use of potassium hydroxide but a A chemical process can be developed but such factors as yield, labor, maintenance, or materials handling can make the process greater amount of residue is also formed using sodium hydroxide. uneconomical. Although the present work has not considered The best result is obtained with potassium hydroxide a t 340' C. all possibilities for synthesis of cresol by sulfonation, it is nevertheand hour, a t which conditions the cresol yield is 71 % and the less possible t o estimate the approximate manufacturing costs total yield with residue is 77%. Data for these runs are given based upon the optimum conditions found in this work. in Table VIII. A number of runs was carried out in which the ratio of potasFor purposes of comparison some figures are presented on phenol costs for sulfonation and chlorination methods. Material sium hydroxide was varied a t 300' C.; these were compared with similar runs in which sodium hydroxide n-as used. The results prices are taken from Chemical and Engineering News. I n the production of phenol the sulfonation step was considered 100% obtained with the use of potassium hydroxide show an increase complete and the fusion step 85% complete. A ratio of Z'/Z in cresol yield from 41% a t a 2 to 1 ratio to 67% a t a 5 to 1 ratio moles of caustic is used in the fusion step and complete use of of caustic to sulfonate. The reaction time was '/z hour. Better by-products for neutralization was considered. Excess sodium yields were obtained in the same time a t higher temperatures sulfite was credited a t the current market price. Based upon with only a slight excess of potassium or sodium hydroxide. From an economic standpoint the use of potassium hydroxide does not seem justified to obtain a RUNS TABLE IX. DATAON ~IISCELLANEOUS small percentage increase in (Mole ratio of reactants, 21/a t o 1; temperature, 340' C.) the yield of cresol. Sulfonation D a t a M I S C E L L A N E O URSU N S . Sodium PSeveral runs were carried out Reaction tolueneTolueneTime, sulfonate, Temp., Tots1 ' Cresol, % sulfonic with samples from those sul% c. Yield Conversion Ortho Meta Para Acid, 70 Run Hr. Run fonation runs in which the final 70 93.3 150 63.2 56.3 13.3 2.0 84.7 84.6 158a 'Iz 72 8 9 . 4 200 41.7 6.0 21.0 73.0 .. 36.6 157Q "*'/z sulfonation temperature was 27.5 15Qa 73 83.7 225 20.6 6.0 20.0 74.0 over 150' C. Table IX shows 161b '/z 76 93.2 HzO off 32.6 26.3 5.0 15.0 80.0 78.'2 172a 1 76 93.2 HzO off 24.7 19.2 4.0 l5,O 81.0 78.2 that the yield of cresol de173b 1 77 84.5 H20 off 27.5 22.3 6.5 15.0 78.5 78.3 creased as the sulfonation temR u n carried o u t with samples from those runs in which the final temperature of sulfonation was raiaed above the reflux temperature. perature was increased. The b Runs carried out with samples in which oleum had been used as the sulfonating agent: there was considerable yield of m-cresol was higher frothing during caustic fusion of sample. than in any other set of runs.
January 1953
4
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
these assumptions the raw material cost for phenol is 7.7 cents per pound. Utilities were taken a t 1 cent per pound and labor a t 1.75 cents per pound, both of which are high but thesamefigures will be used for cresol production. Plant investment was taken as $4,500,000 for a 5- to 10,000,000-pound-per-year plant. If depreciation is taken as 10% of the investment, overhead as IO%, and repairs and maintenance as 15%, the total will be 2.1 cents per pound. The total manufacturing cost for phenol is then 12.55 cents per pound. Data on German phenol production are available in (4, I I ) , from which it is possible to work up some cost estimates for a 13,000,000-pound-per-year plant. Based on raw material costs in the United States the raw materials will cost 10.4, labor 1.8,utilities 1.1, and depreciation, overhead, and maintenance, 2.1 centaper pound, for a total of 15.4 cents per pound. I n the chlorination process a 93% conversion was considered average for the chlorination step and 75y0for the hydrolysis step. Cost of raw materials with credit for by-products was 8.8 cents per pound and the total manufacturing cost was found to be 14 cents per pound. I n Germany the cost of phenol by the chlorination process was estimated to be 16.1 cents per pound. It can be seen that the sulfonation and chlorination manufacturing costs are a little higher in Germany. Since the synthesis of cresol is similar to the manufacture of phenol, such factors as labor, utilities, overhead, depreciation, and maintenance will be similar for similar size plants. The only major difference in manufacturing cost will be in raw material costs. Based on the present work it is possible to obtain 90% conversion in the sulfonation step and 65% conversion in the fusion step. If credit is taken for by-products the raw material cost will be 10.4 cents per pound. The cost of all other factors will be 4.85 cents per pound, for a total manufacturing cost of 15.25 cents per pound. The cresol yield can probably be boosted to 75% with better temperature control andintheabsence of oxygen, in which case the manufacturing cost would be reduced t o 13.85 cents per pound. Because the synthetic cresol mixture contains from 80 to 85% p-cresol, it should sell a t a price somewhere between the market price for mixed cresols from by-product coke ovens and the market price for refined p-cresol. Furthermore, the development of synthetic benzene plants will produce from 1to 2 gallons of toluene for each gallon of benzene produced, so that unless there is sharp
197
increase in the use of toluene the price can be expected to decline which will make the synthesis of cresol from toluene more attractive. LITERATURE CITED
(1) Ambler, J. A., and Gibbs, H. D., U. S. Patent 1,292,950 (Jan. 28, 1919). (2) Aylsworth, J. W., Ibid., 1,260,852 (March 26, 1918) (3) Bender, A., Ibid., 1,301,360 (April 22, 1919). (4) Boehme, BIOS Rept. 1246 (1946). (5) Bouvier, M. E., and Bardin, L. D., U. S. Patent 1,988,156 (Jan, 15, 1936). (6) Brandt, R. L., Zbid., 2,285,390 (June 9, 1942). (7) Brown, W. B., Ibid., 2,362,612 (Nov. 14, 1944). (8) Bull, H., Ibid., 1,247,499 (Nov. 20, 1917). (9) Carr, J. I., Dahlen, M. A., and Hitch, E. F., Ibid., 2,007,327 (July 9, 1935). (IO) Dennis, L. M., Ibid., 1,227,894 (May 29, 1917). (11) FIAT Rept. 768 (1947). (12) Gilman, H., “Organic Syntheses,” Vol. I, New York, John Wiley & Sons, 1932. (13) Groggins, P. H., “Unit Processes in Organic Synthesis,” 2nd ed., New York. McGraw-Hill Book Co.. 1938. (14) Harding, L.,’J. Chem. Soc., 119, 260-2 (1921). (15) Zbid.,PP. 1261-6. EXG.CHEM.,16, 842-5 (16) Harvey, A. W., and Stegeman, G., IND. (1924). (17) Hennion, G. F., and Schimdle, C. F., J . Am. Chem. Soc., 6 5 , 2468-9 (1943). (18) Holdermann, K., Ber., 39, 1250 (1906). (19) Holleman, A. F., and Caland, P., Zbid., 44, 2504-25 (1911). (20) LeMaistre, J. W., Strickland, H. H., and Weaver, J. C., U. S. Patent 2,225,564 (Dec. 17, 1940). (21) Mares, J. R., Ibid., 2,139,372 (Dec. 6, 1938). (22) Marsel, C., D.Ch.E. dissertation, Purdue University, 1945. (23) Othmer, D. F., and Leyes, C., IND.ENG.CHEM.., 33, 158-69 (1941). (24) Potter, H. M., and Williams, H. B., J . Soc. Chem.Ind. (London), 51, 59-60 (1932). (25) Raschig, F., 2.angew. Chem., 13, 795 (1900). (26) Rieman, W., and Neuss, 3. D., “Quantitative Analysis,” New York, MoGraw-Hill Book Co., 1937. (27) Sage, C. E., and Fleck, H. R., Analyst, 57, 567-9 (1932). (28) Shreve, R. N., and Marsel, C., IND. ENG.CHEM.,38, 254-61 (1946). (29) Suter, C. M., “Organic Chemistry of Sulfur,” New York, John Wiley & Sons, 1937. (30) Tyrer, D., U. S. Patent 1,210,726 (Jan. 2, 1917). RECEIVED for review January 7,1952.
ACCEPTED August 28, 1952. Presented before the Division of Industrial a n d Engineering Chemistry at the 120th Meeting of the ERICAN AN CHEMICAL SOCIETY,New York,
N. Y.
Effect of Alkyl Substitution on Antioxidant Properties of Phenols J. I. WASSON AND W. M. SMITH’ Esso Laboratories Research Division, Standard Oil Development Co., Linden, N. J .
P
HENOLIC compounds are used extensively in the petroleum industry as antioxidants for gasoline, lubricating oils, waxes, greases, and other petroleum products. Some phenols possess exceedingly good antioxidant properties for these materials, while others show little or no activity in this respect. A study ha5 been made of the antioxidant Properties of a number of substituted phenols in which the substituent groups consisted of normal, secondary, and tertiary alkyl chains. The products were evaluated in a petroleum-base lubricating oil. 1 Present address, Esso Standard Oil CO., Louisiana Division, Baton Route, La.
DISCUSSION AND R E S U L T S
Most of the alkylated phenols employed in this work were synthesized in these 1aboratories. Methods of synthesis included alkylation of available phenols with olefins or alkyl halides, employing sulfuric acid or Crafts catalysts. The compounds were purified by distillation, crystallization, or by a combination of these methods. Boiling Points and melting Point5 were determined on a mmber of the phenols to aid in identification and this information is shown in Table I, along with data taken from the literature (3, 6). The antioxidant properties of the materiale were evaluated by adding 0.1 weight % of the product to a high quality petroleum-base
