of the salts is desired. Further, addition of potassium salts to the aqueous and/or organic phases would crystallize out the sparingly soluble potassium fluotantalate, K2TaFj. One procedure for recovering all of the tantalum might be to: Contact the extract with NaCl solution Separate the Na2TaF7. H 2 0 crystals; separate the aqueous and organic phases Contact the organic phase with NaF solution (or with a deficiency of dilute NaOH) Separate the NaSl’aF- crystals; separate the aqueous and organic phases; recycle the organic phase to the extraction plant Add K F solution t o the aqueous phase Separate the K2TaF7 crystals; discard the aqueous phase The commercial utilization of this process would depend on whether all three of these salts can be used or sold. Another method would be to contact the organic phase two or three times with NaCl solution. Then either recycle the organic phase back to the extraction plant or contact it with K F solution to remove the last of the tantalum as K2TaF7. The final choice of the scheme chosen will depend upon recovering a maximuin of the tantalum, the salt or salts wanted, and the over-all economics of the process.
Acknowledgment
The author acknowledges the help of F. S. Shuker in making the laboratory experiments and of C. R. McCrossan and G. Stamoulis in the analytical work. Literature Cited
Brethel, C. F., Rothman, H., Keil, W. (to Gesellschaft fur Electrometallurgie an H. C. Stark), Can. Patent 603,147 (Aug. 9, 1960). Eberts, R . E,, Pink, F. X., J . Inorg. Nucl. Chem. 30, 457 (1968). Foos, R. A., Greenberg, H. (to National Distillers), U.S. Patent 3,065,046 (Nov. 20, 1962). Koerner, E. L., Smutz, M., Wilhelm, H. A., Chern. Eng. Progr. 56, 63 (1958). Pierret, J. A., (to Fansteel), U S . Patent 3,117,833 (Jan. 14, 1964). Werning, J. R., Higbie, K. B., Grace, J. T., Speece, B. F., Gilbert, H. L., I d . Eng. Chem. 46, 644 (1954). Werning, J. R., Higbie, K. B., Ind. Erg. Chem. 46, 2491 (1954).
RECEIVED for review July 11,1968 ACCEPTED March 13,1969
ALKYLATION OF BIPHENYL UNDER MILD F R IE DE L- C RA, FTS C0NDIT IONS D U A N E
B.
P R I D D Y ’
Benzene Research Laboratory, The DOLLChemical Co., Midland, Mich. 48640 Biphenyl has been alkylated using mild Friedel-Crafts catalysts which effect the least amount of isomerization of the kinetically favored ortho and para products to products containing high meta compositions. Ethylation, isopropylation, secbutylation, and fert-butylation of biphenyl using a variety of catalysts and alkylating agents gave products containing 0, m, p, oIpr-, m,pr-, and p,p’-substiituted biphenyls in varying ratios, depending only upon the steric bulk and reactivity of the alkylating species involved and not upon the catalyst or alkylating agent.
A NEED in this laboratory to obtain p-alkylated biphenyls prompted an investigation into the possibility of controlling the product distribution obtained in a particular alkylation by the choice of alkylating agent and catalyst. Since it is now established that alkylation of aromatics with aluminum chloi*ide and alkyl halides leads to the formation of considerable quantities of meta-substituted compounds (Condon, 1949; Simons and Hart, 1949), a study was made using alkylating agent-catalyst combinations which would give the kinetically controlled product distribution without concurrent isomerization giving rise to the thermodynamically controlled products containing high meta compositions. A thorough investigation of the product distributions obtained in the alkylation of biphenyl using mild FriedelPresent address: Michigan State University, East Lansing, Mich. 48823
Crafts conditions has never been undertaken using reliable methods of analysis. Thus, mixtures have been reported which contained unbelievably high proportions of the paraalkylated biphenyls (Akhmedov et al., 1962; Romadane, 1957; Romadane and Berga, 1958; Zavgorodnfi and Sidel’hikova, 1958). In the present study, however, combined gas-liquid partition chromatography (GLPC) and infrared techniques were used for separation and structure determination of the products formed. Experimental
Materials. Biphenyl was reagent grade. BF3.H3P04 catalyst was prepared from 99% BF3 (The Matheson Go.) and 85% H 3 P 0 4(ACS grade) (Romadane and Berga, 1958). The alkylating agents were commercial materials, used without purification. The purity, if specified, and suppliers were: methanol, ACS, Fischer Scientific Co.; ethanol, USP absolute, and 2-propanol, U. S. Industrial Chemical Corp.; VOL. 8 NO. 3 S E P T E M B E R 1 9 6 9
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1-butanol, ethylene, c.P.; propylene, c.P., and cis-%butene, The Matheson Co. Reaction. The apparatus was a 250-ml., three-necked flask equipped with thermometer and stirrer. Biphenyl (0.5 mole) was added, followed by the catalyst. If an alcohol was the alkylating agent, a reflux condenser was provided and the reaction mixture, composed of a 1 to 3 mole ratio of biphenyl and the alcohol which had been previously saturated with BF3, was refluxed at 165-70" C. for 5 hours. If the alkylating agent was an olefin, a gas outlet tube was provided and an excess of the olefin was passed through the stirred mixture at 120" to 130°C. for 5 hours. Analyses. GLPC analyses were carried out with an F and M model 720 dual-column gas chromatograph equipped with a 14-foot open tubular column packed with 20% silicone rubber on Chromosorb W 80- to 100-mesh and a thermal conductivity detector. Helium carrier gas pressure of 35 p.s.i. was used a t a flow rate of 70.5 cc. per minute. The column, injection port, and detector temperatures were 235", 295", and 290" C., respectively. The components were trapped and analyzed by infrared analysis in CS2 solutiok in a type 0 cavity using a beam condenser.
Figure 1. GLPC of isopropylbiphenyl product mixture
0
2 3 TIME, HOURS
1
0
4
5
Figure 2. Product distribution with time during isopropylation of biphenyl
Results and Discussion
In Table I are summarized the alkylation reactions carried out in the present work. Isopropylation of biphenyl always gave approximately the same o:m:p ratio of monoisopropylbiphenyls, even though the catalyst, alkylating agent, and conversion were changed. These results prompted a closer investigation of the o:m:p ratio throughout the reaction. Thus an excess of propylene was introduced into a mixture of biphenyl and boron trifluoride-phosphoric acid until no unreacted biphenyl remained in the reaction mixture. Samples were taken during the course of the reaction and analyzed by GLPC. In Figure 1, the GLPC of a product mixture obtained by isopropylation of biphenyl is shown. Figure 2 shows the disappaarance of biphenyl and the relative amounts of the major products formed. The mechanism for the Friedel-Crafts alkylation of biphenyl basically appears to be
-
RX + c a t a l y s t
-
+
Xcatalyst
R@ +
x
catalyst
-
+
HXcatalyst
The catalyst complexes with the alkyl derivative to form a polarized complex; this then reacts with biphenyl to form a a-complex; and loss of a proton from the a-complex yields alkylbiphenyl. This mechanism indicates that the alkylbiphenyl product distribution obtained, and therefore the selectivity of the reaction for the activated
Table 1. Product Distributions in Alkylation of Biphenyl
Alkylating Agent
Catalyst
Conuersion, %
MeOH' EtOH' C2H4 C3Hs C3H6 i-PrOHb i-PrOH: n-PrOH n-BuOH S-BuOH
BF3 BF3 BFJ.HJPO~ &SOa BF3 * BF3 BF3 .H3POa BFB BF3 BFJ
tert-BuOH C4Hs'
BF3 BFJ * HaPo,
12 83
CaHB
BF3.H3POa
26
0
1 8 1 100 100 69 17 72 67 44
m
P
... ...
32.5
... ...
30.2
33.3
...
22.0 21.6 33.2 36.8 32.6 17.0 17.9
11.8 12.0 18.1 22.1 17.8 10.0 10.2
0
12.8
6.7 6.1
0
6.6
16.2 16.6 26.8 28.3 26.2 24.5 25.8 3.0d 95.3 22.2 13.8d 95.5
...
0,P'
... ...
m,p'
and p,p'
... 3.8'
...
35.8 36.1 16.8 9.5 17.5 36.1 34.0
14.2 13.7 5.2 3.7 5.8 13.0 9.0
0 35.6
0 9.5
0
0
Concentration of all catalysts except BF3, 3% by weight of biphenyl. Run in pressure apparatus. e Combined weight per cent. dtert-Butylhiphenyl . cis-2-Butene. Is0 butylene, a
~~
240
~
I & E C PRODUCT RESEARCH A N D DEVELOPMENT
positions of the biphenyl ring, is significantly affected by the amount of polarization of the R X bond that precedes reaction with the aromatic ring. If the polarization of the R X bond is nearly complete before reaction with the aromatic ring, the selectivity of the reaction is relatively independent 01 the nature of the X and catalyst involved. This study shows this to be true. Since equal selectiviity implies equal reactivity (Brown and Nelson, 1953), the enormous increase in conversion by alkylation of biphenyl with isopropyl and s-butyl cations over methyl and ethyl cations cannot be due to increase in reactivity of the cations, but must be due to the relative quantities of formation of the polarized alkyl species. Comparison of the o:m:p ratios obtained by ethylation, isopriopylation, s-butylation, and tertbutylation shows the expected respective increase in para selectivity due to increasing bulk and decreasing reactivity of the respective catioiis.
Literature Cited
Akhmedov, Sh. T., Gadzhiev, G. Yu., Salimov, M. A., Uch. Zap. Azerb. Gos Univ., Ser. Fiz. Mat. Khim. Nauk 1962 (4) 66 (1962). Brown, H. C., Nelson, K., J. Am. Chem. SOC. 75, 6292 (1953). Condon, F. E., J . Am. Chem. SOC.71, 3544 (1949). Romadane, I., Latviijas Valsts Univ. Khim. Fak., Zinatniskie Raksti 14, 49 (1957). Romadane, I., Berga, S., Zhur. Obshch. Khim. 28, 413 (1958). Simons, J. H., Hart, H., J . Am. Chem. SOC.69, 979 (1949). Zavgoradnfi, S. V., Sidel’hikova, V. I., Dokl. Akad. Nauk SSSR 118, 96 (1958).
Acknowledgment
The author thanks \N.J. Potts, Dow Chemical Physical Research Laboratory,, for the infrared analyses and interpretation.
RECEIVED for review August 19, 1968 ACCEPTED July 7, 1969
A MODERN BUILDING MATERIAL FROM ASPHALT AND SOIL D.
T .
ROGERS
A N D
J .
C.
M U N D A Y
Esso Research and Engineering Co., Linden, N . J . 07036 A process is described for the manufacture of a new building material from asphalt and soil which is competitive with conventional masonry products in compressive, tensile, and flexural strength, excels in water repellency and freezetha,w resistance, and has low cost. This type of product, known as BMX, can be manufactured within such close tolerance that very thin (Xe-inch) mortars can be used. These mortars, composed of cement, organic adhesives, and fillers, can be applied with paint rollers, resulting in substantially lower labor costs. The higher quality products made from carefully selected soils can be used below grade without water-proofing treatment. The products are compatible witlh all types of water- and oil-based paints, and because of low porosity absorb much less paint than other masonry products. Durability tests, some of which have been in progress for seven years, indicate a high degree of stability.
SOIL is a widely used construction
material; more than half the world’s people live in houses made of soil (United Nations, 1963). It is cheap, abundant, and readily available in the localities where it is needed. On the other hand, it has such low dry strength that it is satisfactory only for thick-walled low-rise buildings, and most of this strength is lost when wet. Many attempts have been made to waterproof soil and to increase its strength. Asphalt is one of the lowest cost and most effective soil waterproofers. Its use for this purpose goes back some 6000 years, but it has not been used much in modern times in building construction. During the 1930’s theire were attempts to introduce soilasphalt building blocks in the southwestern United States, and one product (developed by the Chevron Asphalt Co.)
is currently in use in new construction in certain areas of California. The blocks are made by mixing carefully selected soils and asphalt emulsions, followed by molding and sun-drying (McKesson and Watts, 1942). It is exceptionally waterproof, but since asphalt employed in this manner does not strengthen the soil, blocks are generally not strong enough to be of widespread interest for housing in the developed countries. Portland cement and lime have also been used to improve soil as a building material. Both improve both dry and wet strength, cement much more than lime. Most soil-cement and soil-lime products, although strong enough not to be disrupted by water, soak up water avidly and allow it to permeate through walls built of the material. They also perform poorly under freezing and thawing conditions. Soil-lime products VOL. 8 NO. 3 S E P T E M B E R 1 9 6 9
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