CATALYTIC HYDROLYSIB OF CHLOROBENZENI
727
CATALYTIC HYDROLYSIS OF CHLOROBENZENE IN THE VAPOR PHASE ARTHUR A. VERNON1
AND
FRANCIS X. THOMPSON'
Department of Chemistry, Rhode Island State College, Kingston, Rhode Island Received September $0, 1989
Owing to its commercial importance, the catalytic hydrolysis of chlorobenzene has been the subject of several patents. Jenkins and Norris ( 5 ) described a method of recirculating steam and chlorobenzene over silica gel at 550°C. They also found that passage of the vapors over copper shavings helped to maintain the catalytic activity of silica gel impregnated with metals. Lloyd and Kennedy (6) and Rittler (8) reported the formation of phenol from steam and chlorobenzene vapor by the use of silica gel and aluminum hydrosilicates. Groggins (4)describes the Raschig process for the formation of phenol from chlorobenzene and steam, using silica gel as a catalyst. The hydrochloric acid produced is used to chlorinate benzene by a regenerative process. He (3) also states that in pilot plant operations high yields of phenol have been obtained using silica gel as a catalyst. Bertsch (1) used catalysts with strong base-exchange properties for the same reaction, while Steingroener and Zellman (9) found that small additions of inorganic salts increased the catalytic activity of zinc oxide and aluminum oxide for the reaction. They found that the ratio of steam to hydrocarbon halide was important, and Lloyd and Kennedy (7)showed that an excess of steam increased the yield when catalysts such as silica gel, bauxite, and oxides of certain metals were used. Chalkey (2) steamdistilled chlorobenzene over silica gel and oxides of titanium, tungsten, zirconium, and aluminum. The highest yield of phenol was 68.5 per cent of the amount hydrolyzed when silica gel at 500°C. was the catalyst. Tishchenko, Gutner, Faerman, and Shchigelshaya (10) found that the most favorable temperature for hydrolysis of chlorobenzene was 5006OO"C., using chlorides of calcium, strontium, barium, magnesium, and copper on silica gel. In the course of some work on catalysis, it was desired to carry out experiments on hydrolysis in the vapor phase. The data obtained when chlorobenzene was used ape presented in this paper. Present address: Department of Chemistry, Northeastern University, Boston, Massachusetts. * Present address: Department of Chemistry, Seton Hall College, Newark, New Jersey.
728
ARTHUR A, VERNON AND FRANCIS X. THOMPSON EXPERIMENTAL
Material The catalyst supports were silica gel of 8 to 12 mesh prepared by the Davison Chemical Company, activated alumina of 8 to 12 mesh supplied by the Aluminum Ore Company, and carborundum No. 8 furnished by the Carborundum Company. All chemicals used in the preparation of the catalysts were of C.P. grade. The chlorobenzene was used as obtained from the Eastman Kodak Company. TABLE 1 Catalytic hydrolysis of chlorobenzene
I
1 CATALTBT
i 1
BPACCEVELQCITY
i
TEMPBBATUBE
--__
-
Chlorobencene
n E L D OW
PHENOL
Retio
CELOBO3ENIENII HYDBCLTZCED
- --
QC.
T l m D ON BMII) O? L Y O W
ow
~OROBCENZ l N l ETDBOLTECD
per cent
p a cent
P R Cent
A120a (alfrax)
440 510 575
23,380 269 24,965 499 25,260 368
86.8 50.0 68.7
2.2 1.0 4.1
5.6 3.72 16.6
38.5 27.0 24.6
Cu(NOs)z on SIOS
510
24,965 598
41.7
1.9
9.5
20.0
Cu&ll on Si08
510
27,705 188
147.3
10.1
27.0
40.0
SnV03 on Si02
440 510
24,350 844 27,705 507
28.8
0.8 3.1
2.0
40.0 55.2
54.8
5.6
-
Catalysts The oxide catalysts used were zinc oxide, nickel oxide, molybdenum trioxide, and titanium oxide on silica gel, as well as tungsten trioxide on alfrax, and magnesium oxide on silicon carbide. The salts tested were tin vanadate, cadmium phosphate, copper phosphate, copper nitrate, copper sulfate, and cuprous chloride on silica gel. Granular copper, a coppercobalt mixture, silica gel, and alfrax were also tried. Method Water and chlorobenzene were introduced into a heated silica tube containing the catalyst. The exit gases passed through a water-cooled condenser and then through an absorption bottle containing standard potassium hydroxide. The amount of hydrolysis was determined from the hydrochloric acid produced, and the phenol by the iodophenol method.
CATALYTIC HYDROLYSIS O F CHLOROBENZENE
729
Results With the experimental set-up used the space velocities were necessarily high. Expressed as liters of gas at the reaction temperature per liter of catalyst per hour, the space velocity of chlorobenzene was varied between 25 and 5OO0, while the ratio of water to chlorobenzene a t the different space velocities was varied between 10 and 150. The lowest temperature a t which any activity was evidenced was 400OC. The highest temperature which could be used was 575"C., and a t this temperature much carbonization was evident. The yield was favored by an increase of the waterchlorobenzene ratio and by a decrease in the space velocity with the ratio constant, I n the temperature range and space velocity variation given above the only catalysts besides silica gel which gave any more than 0.1 per cent of phenol were alfrax, copper nitrate on silica gel, cuprous chloride on silica gel, and tin vanadate on silica gel. Typical results for these catalysts are given in table 1. Discussion Under the conditions shown in table 1, silica gel gave a maximum yield of about 10 per cent phenol and a yield of about 60 to 70 per cent based on the amount hydrolyzed. The copper compounds which decompose do not give as good activity as cuprous chloride; this was substantiated by experiments with copper oxide and copper sulfate on silica gel. The per cent of hydrolyzed chlorobenzene which goes to phenol is as important as the per cent hydrolyzed. With aluminum oxide as the catalyst the per cent of chlorobenzene hydrolyzed increases with temperature, but the phenol yield does not increase proportionally. Tin vanadate has not been reported before as a catalyst for this reaction. It seems to give a lower side reaction than many other substances and might bear further investigation. Data on space velocities are very scant in the literature, and from these results it is evident that they must be low to obtain a reasonable yield per pass. SUMMARY
Experiments with a number of unreported catalysts for the hydrolysis of chlorobenzene have been made, and of these tin vanadate on silica gel has-been found to be the best. Data on space velocities are presented which have not been reported in the literature before, and it is concluded that they must be fairly low for reasonable yields. REFERENCES U. S. patent 1,9G6,281(1931). (1) BERTSCH: (2) CHALKEY: J . Am. Chem. SOC.61, 2489 (1929).
730
CUSTAV EGLOFF, f . SHERMAN, AND R . E. DVLL
(3) GROffffINs: Unit Processes i n Organic Synthesis, p. 630. McGraw-Hill Book Company, New York (1938). (4) Reference 3, pp. 631-2. U. S.patents 1,950,359(1934)and 1,844,710(1932). (5) JENKINSAND NORRIS: AND KENNEDY: U. S. patent 1,735,327(1929). (6) LLOYD (7) LLOYDAND KENNEDY: U. S. patent 1,849,844(1932). (8) RITTLER: u. s. patent 1,936,567 (1933). AND ZELLMAN: U. S. patent 1,961,834(1931). (9) STEINOROENER (10) TISHCHENKO, GUTNER, FAERMAN, AND SHCHIGELSHAYA:J . Applied Chem. (U. S. S.R . ) 8, 685-94 (1935).
BOILING POINT RELATIONSHIPS AMONG ALIPHATIC HYDROCARBONS' GUSTAV E G L O F F , J . SHERMAN,
AND
R. B. DULL
Research Laboratories, Universal oil Products Company, Chicago, Illinois Received October 9, 193'9 INTRODUCTION
The boiling points of the paraffin, olefin, and acetylene hydrocarbons have recently been collated (3)* and evaluated critically. A correlation of the data, as dependent upon molecular structure, becomes important in order that its consistency may be checked and that boiling points for those compounds where data are lacking may be calculated with the same order of accuracy as the experimental data. I n 1842 Kopp ( 5 ) announced that in any homologous series the boiling point rises 18' for the addition of each methylene group to the molecule, but he soon recognized that the increase in boiling point became less with increasing size of the molecule; since then many attempts have been made t o correlate the data. Each of these efforts need not be individually considered here. However, in order to show the diverse forms of boiling point equations used, a representative list is given in table 1. Each of the equations given in table 1 has certain disadvantages which need not be considered in detail. I n general, it may be said that the early workers frequently expressed the boiling point as a function only of the molecular weight, and consequently all isomers yould have the same calculated boiling point. The data of this early period were too limited and 1 Presented before the Division of Physical and Inorganic Chemistry at the Ninety-eighth Meeting of the American Chemical Society, held in Boston, Massachusetts, September 11-15, 1939. * The boiling point data in this paper are taken from reference 3.
