AND FILM CORPORATION, NEW YORK, N. Y.
catalytic reduction of nitro5leAns to saturated amines and nitroguanidines to aminoguanidines was reported. A patent was granted on a method for the continuous reduction of aromatic nitro compounds, using metal sulfides as catalysts. The catalytic reduction of water-immiscible polynitro compounds in a water dispersion was developed. A study was made of the activity and reproducibility of palladium-on-charcoal catalysts. A new, foamlike, nonpyrophoric, active nickel catalyst was developed. Conditions for various electrolytic reductions were studied. Miscelianeous reductions using stannous chloride, zinc and alcoholic alkali,sodium hydrosulfite, and lithium aluminum hydride were described.
nickel catalyst for tlie reductiou of nitro compounds. This catalyst is prepared hy tlie treatment of tin aqueous solntion of a nickel salt with alkali to produce riickelous hydroxid?, which is then reduccd with hydropc~n at 80" to 150" C. undc,r 40 to 60 a t m o e p l i e r e s p r c s ~ u r e . r1 . he cataly5t can be r~gciier:itrd by tlic sanic general treat-
I S C E December of 1952, very little work of a fundaniental or novel nature in t,he chemical or chemical engineering aspects of the unit process amiiiation by reduction has been published. Most of the papers and patents involve extensions of the present state of the art. For the first, time since these I,rvie\?-s started, no work of any significance Tyas reported on the Bechaiiip method of reduction and on sulfide reductions. As has been true in the past, most of the published work was devot,ed TO catalytic reduction, including the reduction of new materials and development of new techniques. This review will be divided int,o three sections, namely, catalytic reduction, electrolytic reduction, arid miscellaneous reductions.
ment after us?.
ELECTROLYTIC REDUCTION
n ( I S ) has studied tlie electi~olyticreduction of oo-pherivlenediamine in alcoholic caustic EO&, using copper, plhtinum, aluminum, nickel, zinc, arid lead cathodrs. The yield was greatest with a lead cxthode and increased of current density. ?i similar study on nitrobenzoic. ai'ids was reported by IzgarJ-shev :ind Fioshin (; ). They found that lend, tin, or ainal ated zinc cathodes gavc (35 to 98% yirldq on all three isom and coppcr or graphite ill the presence of copper chloride ga illy slightly lower yields. T h e concent.ration of hydrochloric ai.id, uscd as c*atholytc>,had little effect on yield. K h e n lead was used, a high current density was required. Optiniuni temperat,urcv of rmction iric ortho to meta to para.
CATALYTIC REDUCTION Tindall ( 1 4 ) has obtained a patent on the reduction of nitroolefins to saturated amines using hydrogen, Raney nickel catdyst in an organic acid and organic solvent, pressures of 500 to 2000 pounds per square inch, and temperatures of 30" to 100" C. Lieber and associates (5) described the reduction of nitroguanidine and aniinonitroguanidine with both hydrogen and platinum oxide and with zinc dust and acetic acid. il patent r a s issued to Munday (8)of Standard Oil Development Co., on the continuous catalytic reduction oi nitro aromatics ueing metallic sulfides (activat,ed with hydrogen eulfide) as catalysts and temperatures of 400" to 550" F. This is along the lines of Standard Oil's extensive World War I1 program on the production of xylidine for aviation gasoline. hnother patent has been granted to Benner and Stevenson ( I j of Du Pont on the catalytic reduction of water-immiscihle aromatic polynitro compounds that form water-soluble polyamines. The reductions, bstchmise or continuous, are carried out ill r a t e r with very rapid agitation to form dispersions of the nitro compounds. The resulting diamines, particularly m-toluj-lenediamine, are intermediates for diisocyanates, which are becoming increasingly important for the production of flexible foams: rigid foame, and n e v qnthctic rubbere. Delaby and associates (3) have rcport,ed the hydrogenation oE p-nit,robenzoates of P-hydroxyalkylurethans using Itaney nickel in organic solvents. Robins and associates (9) described the reduction of various nitropyrimidines using hydrogen and Raney nicltel or zinc and ammonium hydroxide. Young and associates ( 1 6 ) have studied the activity and rcproducibility of various palladium-on-charcoal catalysts hy various standard reduction systems, including the reduction of nitrobenzene and piperonal oxime. The activities of the catalysts were studied, and reproducibility was poor. These authors postulat,e that this is due to random formation of "active centers." Schxeiz. Sprengstoff-Fabrik 8.-G. (10) has been granted a British patent on a new foamlike, nonpyrophoric, very active
Bechamp Reduction Kettle at General A n i l i n e & Film Carp., Rensselaer, N. Y.
I3cic~ov~kii and S'aikov (2)repoi ttd a study of tlic elcctiolytic icduetion of 2-chloromcth~-l-4-nitiotolueiie to XJ lidine. T l i ~ y found zinc the beet cathode and 75% aqueous ethanol in the piescnce of hulfuric acid the best catholyte. The anode used 15a~ lead 1800
INDUSTRIAL AND ENGINEERING CHEMISTRY
September 1954
MISCELLANEOUS REDUCTIONS
1801
of the same types of compounds using Raney nickel in alcohol and
Miscellaneous reductions reported since December 1952 include stannous chloride in acid, zinc and alkali, sodium hydrosulfite, and lithium aluminum hydride. Shimizu and Xakazawa (12) have described the reduction of 3-isonitrosoflavanone t o 3-aminoflavanone using stannous chloride in a mixture of acetic and hydrochloric acids. Manabe and associates (6) reported the reduction of o-nitroanisole with zinc dust in the presence of methanol and sodium hydroxide to 2,2'diinethoxyhydrazobenzene, which can be rearranged with hydrochloric acid to give dianisidine. A patent was granted to 'Cl'erner (15) on the reduction of aromatic nitro compounds containing a labile halogen atom ortho or para t o the nitro group, without reducing the halogen atom. The reduction is carried out with sodium hydrosulfite in an aqueous solution of a tertiary amine, preferably a tertiary ring nitrogen compound such as pyridine or picoline. Shaw and Woolley ( 1 1 ) reported the reduction of a series of nitroindoles to aniinoindoles using sodium hydrosulfite in alcoholic sodium hydroxide solution, They found that other reducing agents resulted in mixtures. Zaugg and Horroni ( I 7 ) attempted to reduce 2,2-dipheny1-3dialkyl-aminopropionitrile to the corresponding 1,3-propanediamines and found catalytic reduction and reduction with sodium and ethanol resulted in cleavage, whereas lithium aluminum hydride gave a smooth reduction. hlazoni ( 7 )reported reduction
lithium aluminum hydride.
LITERATURE CITED (1) Benner, R. G., and Stevenson, A. C. (to E. I. du Pont de Nemours & Co.), U. S.Patent 2,619,503 (Nov. 25, 1952). (2) Bereeovskil, V. M., and Varkov, V. S., Zhur. Obshchei Khinz., 23, 100-6 (1953). (3) Delaby, R., Sekera, A., and associates, Bull. SOC. chim. France, 1953, pp. 273-5. (4) Izgaryshev, N. A,, and Fioshin, M. Ya., Dolelady Akad. Sauk S.S.S.R.. 90, 189-90 (1953). (5) Lieber, E., and associates, J. Org. Chem., 18, 218-28 (1953). (6) Manabe, O., and associates, Sci. I n d . , 27, 7-14 (1953). (7) Maeoni, D., Compt. rend., 236, 1898-1900 (1953). (8) Munday, J. C. (to Standard Oil Development Co.), U. S.Patent 2,620,356 (Dec. 2, 1952). (9) Robins, R. K., Didle, K. J., and associates, J . Am. C h m . SOC., 75, 263-6 (1953). (10) Schweiz. Sprengstoff-Fabrik A-G., Brit. Patent 692,268 (June 3, 1953). (11) Shaw, E., and Woolley, D. W., J . Am. Chem. Soc., 75, 1877-81 (1953). (12) Shimizu, M., and Nakazama, S.,,J. Pharm. SOC.Japan, 73, 522-3 (1953). (13) Ter-Minasvan. L. E.. ZAur. Fiz. Khim., 27. 719-23 (19.53). (14j Tindall, J.? B. (to Commercial Solvents Corp.), U.' S. Patent 2,636,901 (April 28, 1953). (15) Werner, J. (to General -4niline & Film Corp.), Ibid., 2,631,167 (March 10, 1953). (16) Young, J. G., and associates, J . Org. Chem., 18, 229-34 (1953). (17) Zaugg, H. E., and Horrom, B. W., J . Am. Chem. Soc., 75, 292-4 (1953). .
I
ESTERIFICATION E. EMMET REID PO3 E. 3 3 R D STREET, B A L T I M O R E 18, MD.
This year, more than ever, attention has been given to the kinetics and mechanism of esterification. There is little new on catalysts. There are several novel ways of making esters. There are many articles and a host of patents on phosphoric and silicic esters. Titanium compounds
fication of glycerol (140, 680, 641)T h e rates for the polyesterification of acid phthalic esters of ethylene glycol have been measured a t 150°, 160", and 170' C. Reducing the amount of glycol favors formation of phthalic anhydride (19Zb). The esterification of a polyalcohol resin by a fatty acid is a second-order reaction. The relation of activation energy to collision frequency has been discussed (178). I n the esterification of glutaric acid by methanol, with or without an acid catalyst, the first product that can be detected is the diester (8.42). A primary alcohol can be estimated, in the presence of secondary and tertiary, by quick esterification (159, 260). T h e oleic acid in a mixture with resin acids can be selectively esterified (107). Several acids having isotopic carbon in their carboxyls have been converted t o their ethyl esters. The yield of labeled ethyl acetate was 98% but the yields were considerably lon er with other acids ( 7 ) . The rate of saponification of PhC1402Et was 93% of t h a t of PhCOzEt. The presence of RleO, C1, or Me in t h e para position lowered the rate slightly while C1 or NO, in t h e meta position raised it ( 1 7 7 ) . The preparation of esters of perfluoroacids with prrfluoroalkylcarbinols has been studied (86). T h e stereochemistry of the formation and hydrolysis of the esters of perfluoroacids
are becoming important. There is scientific as well as practical interest in polyesterification.
A T T E M P T has been made to call attention to the more novel and suggestive items that have appeared concerning esterification, considered in the broad sense. For the most part dependence has been on Chemical Abstracts, with a time limit of April 1954. As this involves a time lag some of the references are more than a year old. It has long been assumed t h a t the first step in esterification is the addition of the alcohol to the acid: MeCOOH
+ E t O H + MeC(OH)20Et
Analogous addition compounds must be intermediates in transesterification and the saponification of esters. This assumption has received confirmation by infrared studies. When sodium ethylate is added to a solution of ethyl trifluoroacetate the carbonyl band vanishes, indicating that the formation of F$C( 0Et)( 0 N a ) O H is 99% complete (22). The reaction of this with a dialkyl sulfate gives an ortho ester, which checks this structure (80). The stepwise esterification of glycerol has been reviewed with 72 references (227). Kinetic studies have been made of the esteri-
