ATION -
WILLARD dec. CRATER HERCULES POWDER COMPANY, WILMINGTON, DEL.
During the past year few articles have been published on nitration processes. The most important literature contributions on nitration during this period deal with the mechanism and kinetics of nitration. M a n y of these articles have as their premise the proof of the existence OF the nitronium ion (NO2+),while others cover its role as a nitrating agent. It is also shown that an effective dehydrating agent not only reacts with the water liberated, but also ionizes the nitric acid to yield proton-attracting agents, which in turn accelerate the nitration reaction.
HIS review is a continuation of the review of nitration processes and the mechanism of nitration presented for the past 3 years (9-11). It covers nitration in its broadest sense-that is, the treatment of organic compounds Kith nitric acid or its equivalent to produce both nitrates and nitro compounds, as indicated by the follon-ing equations:
T
+ IIOXOn --z RH + HOTOI --++
ROII
+ HOH RNO, + HOH RON01
(1) (2)
NITRIC ACID ESTERS Aubertrin ( 1 ) investigated the nitration of the glycols, especially diethylene and triethylene glycol. H e also studied the solubilities of the nitrates of glycerol, ethylene glycol, diethylene glycol, triethylene glycol, and of the butanediols in various mediums. The action of nitric acid-sulfuric acid mixtures on these compounds was studied too. The continuous preparation and the properties o'f nitropentaglycerin (methyltrimethylolmethane t,rinitrate) is described by Colsori (8) who hdicates t h a t this compound is a n eventual substitute for nitroglycerin. A study was made by Desseigne (12) of using various mixtures of nitric and sulfuric acids to effect the nitration of methanol. H e also deac: jbed a continuous nitrating apparatus, made entirely of borosiiice,t,e glass, for manufacture of methyl nitrate. The renc?ivity of cellulose toward nitration was investigated 1); Rosenthal and Brown (32). When dewaxed cotton linters lvcrc altcrnat,ely immersed in distilled water and dried directly, it x a s found that the degree of nitration with standard nitric nciti-sulfuric acid--mater mixture increases with the number of times the cellulose is wetted and dried. The magnitude of the change in reactivity depends on the sharpness of drying and on the number of wetting and drying cycles. According to the authors, their results support the belief that the variable moisture history of cellulose may be partly responsible for its occasional anomalous behavior toward reagents. Thinius (34) discussed the esterification of cellulose with nitric :irit3, nitration processes, the working up of the waste acid, and thv action of nitric acid on wood. Other cellulosic derivatives mid their uses are discussed and 25 references are given. The nitration of cotton linters by immersion in and by pouring on of baths diluted with varying proportions of carbon tetrarhloride are described by Brissaud ( 5 ) . Watanabe (58) investigated the nitration of cellulose by a chloroform-acid system. Jessup and Prosen (28) studied the heats of combustion and fiirmation of cellulose and nit'rocellulose. They give the results of bomb calorimetric measurements of heats of combustion at, 30" C. of one sample of cellulose and four samples of nitrocellulose from cotton linters and wood pulp, respectively. The results were combined with values for the heats of formation of carbon dioxide and water to obtain heats of formittion of the cellu-
lose and nitrorpllulose s a m p l e s . Empirical equations were derived expressing the heat of combustion and the heat of formation of the nitrocelluloses as functions of the nitrogen content. The nitration of starch was studied by Israelashvili (27) who observed that, ( a ) an equimolecular mixture of water, nitric acid, and sulfuric acid leads to the formation of nitric esters of lo^ nitrogen content (7.1%); and ( b ) the degree of nitration of starch is controlled by the proportion of mater and free sulfur trioxide, respectively, in t'he nitrating mixture. The nitrogen content of nitrated starch increases as the mater is decreased and the sulfur trioxide is increased. By using mixtures of pure nitric acid and oleum (2 to 370 sulfur trioxide), nitrates of starch containing about 13% nitrogen are said to be easily obtained. The author suggests t h a t the active nitrating agent is the positive nitronium ion (NOz+) and that conditions which favor its formation are conducive to the production of nitrates of high nitrogen contmt.
NITRO COMPOUNDS Clarkson and coworkers (7) investigated the course of reaction of the nitration of dimethylaniline to tetryl. Their results show that the formation of tetryl proceeds in two s t a g e s 4 i m e t h y l aniline gives 2,4-dinitromethylaniline which in turn gives tetryl. Although the latter stage proceeds largely as above, it also takes place via dimethylpicramide. The first stage is catalyzed by means of nitrous acid, probably due to the formation of nitronium ions from nitrogen tetroxide (N20,); the second stage is accelerated in a different manner, as nitrous acid is found to be a powerful demethylating agent. These authors also discuss the mechanism for the format,ion of methylpicramide from 2,4-dinitrophenylnitramine. Edwards (14) reports results obtained in the laboratory on thc anodic nitration of toluene versus nitration by the conventional method and includes a description of t,he apparatus used. Comparison of the chemical and electrochemical method of nitration of toluene showed t h a t t,he rate of reaction is slightly higher under electrochemical conditions and that the increase is not due only to high temperatures in the immediate vicinity of the anode. A discussion is given by Kratz (29) of the w s t e water disposal problems which arose in conjunction n-ith the large production increase of trinitrotoluene (TKT) plants during the war yrars. Xeutralization of the large volumes of acid waste waters mith lime clarification, dewatering, and calcination of the mud as well as various recovery methods are described. This articlc is of interest to those engaged in nitration as well as to industi whole from the standpoint of the disposal of large volumes of waste water to amid stream pollution. This is a serious problem and industry should take all precautions possible to prevent it. Some nitro derivatives are difficult to prepare by direct nitration, particularly some isomcrs-e.g., certain dinitronaphthalcries. Such compounds can often be prepared by indirect methods. Hodgson and coworkers (22) have prepared and published a r e view of such indirect methods applicable primarily to naphthalcne chemistry. Such proccdwcs often comprise the nitration of an
1987
1988
INDUSTRIAL AND ENGINEERING CHEMISTRY
intermediate, which in turn reacts with another compound to give the desired end product. A process for preparing coarse free-flowing crystalline cyclonite was patented by Willson et al. (40). This process comprises the addition of the nitration mixture (resulting from the addition of hexamethylenetetramine to concentrated nitric acid) with agitation to a heated dilution medium of weak nitric acid (50 to 70% acid) containing a small quantity of sodium nitrite or paraformaldehyde. The temperature of the dilution medium is maintained between 40” and 90” C., preferably within the range of 65” to 75” C. The by-products start decomposing immediately with a temperature rise, which is controlled within the desired range by external cooling. The decomposition gases, which are rich in oxides of nitrogen, are drawn into a fume system and recovered by passing them through a suitable absorption system. Vroom and WinlJer (37) studied the direct nitration of hexamine to give cyclonite. They isolated an intermediate which was identified as 3,5-dinitrocyclotrimethylenetriamine-l-nitrate. According to the authors this is a true intermediate and its reaction to cyclonite is the rate-controlling step in the direct nitration of hexamine. The mechanism of the over-all reaction is discussed. The nitration of 1,3dicyclohexylimidazolidine and of hexamethylenetetramine has been compared by Boivin and Wright ( 4 ) . It was found t h a t when formaldehyde splits off to leave a weakly basic amine, as in the case of hexamethylenetetramine, subsequent nitration will occur; but it will not take place if the resulting amine is strongly basic. Nitratio? also depends on the reactivity of the nitric acid, the activity of which can be decreased by addition of ammonium nitrate. This decrease will prevent nitration of intermediate N-methylolamines but not of the hexamethylenetetramine types; thus the nitration of dicyclohexylimidazolidine is prevented. On the other hand, the two nitrations are related by the fact that both are accelerated by electropositive chlorine. Bachmann and coworkers (3) describe the preparation of ethylenedinitramine, N02NHCH2CH2NHN02, from ethylenediamine, Starting with ethylenediamine, a series of intermediates (such as Zimidazolidone, ethylenebisurethan, ethylenebisacetamide, and cyclic ethyleneoxamide) were prepared and then nitrated to their respective dinitro derivatives. These dinitro derivatives are readily converted to ethylenedinitramine by alkaline hydrolysis or by ammonolysis. Bachmann and his coworkers also investigated the possibility of using ethylenebisurea for preparing ethylenedinitramine. They found this compound is nitrated at the terminal amino groups only. I n order to nitrate ethylenebisacetamide and cyclic ethyleneoxamide, these workers found it necessary to use a mixture of 98% nitric acid and acetie anhydride. The use of 98% nitric acid alone or mixed with concentrated sulfuric acid was without effect on either of these compounds. The various factors affecting the preparation of nitroguanidine by reacting dicyandiamide with sulfuric acid and nitrating the resulting guanidine sulfate was studied by Aubertein (2). Under optimum conditions a 90% theoretical yield was obtained.
M E C H A N I S M AND KINETICS The mechanism and kinetics of nitration has been a subject of wide investigation during recent years. Hughes, Ingold and coworkers published a series of articles during the fall of 1950 discussing the formation of the nitronium ion (NOz+), the existence of which has been proved by cryoscopic study. Under the general heading “Kinetics and Mechanism of Aromatic Nitration,” Hughes, Ingold, and Reed ($3) studied the kinetics of aromatic nitration by the nitronium ion (NOS+) derived from nitric acid. P a r t I1 of this series of articles is divided into four p a r t discussing the following: 1. Kinetic Orders of Aromatic Nitration: The Xitronium Ion.
Vol. 43, No. 9
2. Solute Effects of Nitration Kinetics: Mechanism of Formation of the Nitronium Ion. According to these authors, this is a two-stage mechanism proceeding as follows: 2HNOa
e H2NOa+ + NOI-
H2N03+
+ NOz+ $: H20
(fast)
(slow)
3. Medium Effects on Nitration Kinetics: Mode of Action of the Nitronium Ion. The results of this study indicate the nitrating attack to be a two-stage bimolecular process:
+ NOg+ + Ar+H(N02) Ar+H(N02) --+ ArNO2 + H +
ArH
(slow) (fast)
4. Effects of Nitrous Acid on Nitration Kinetics: Condition of Nitrous Acid in Nitric Acid Solvents. In this case the term “nitrous acid” is used to cover all materials in nitric acid t h a t after dilution with water together could be estimated as nitrous acid, The author found t h a t aromatic nitration in nitric acid or in nitromethane or acetic acid with nitric acid in constant excess is retarded by nitrous acid. Halberstadt, Hughes, and Ingold ($0)continued the investigation in p a r t I11 on Nitration in Acidified Aqueous Nitric Acid. They investigated the nitration kinetics of 2-phenylethylsulfonic acid and of benzylsulfonic acid in aqueous solutions of nitric acid containing some perchloric or sulfuric acid. Their results show t h a t in these mediums the nitrations uniformly follow a first-order law. P a r t IV of this series by Gold, Hughes, Ingold, and Williams (18) covers the kinetics of nitration by dinitrogen pentoxide in aprotic solvents, such as carbon tetrachloride. The authors point out t h a t such kinetics a r e complicated, but that analysis shows there is a simple limiting kinetic form which is distinguished as the uncatalyzed reaction; and upon this may be superposed one or more of a family of reactions, all catalyzed by nitric acid. The uncatalyzed reaction is interpreted as a nitrating attack on the aromatic molecule by the covalent dinitrogen pentoxide, whereas the catalyzed reactions a r e regarded as nitronium ion reactions, resulting from the ionizing action of nitric acid on dinitrogen pentoxide. P a r t V covers nitration by acyl nitrates, particularly by benzoyl nitrate. Gold, Hughes, and Ingold (17)established that benzoyl nitrate exerts its nitrating action through a small stationary concentration of dinitrogen pentoxide formed along with benzoic anhydride. Gillespie, Hughes, and Ingold (16)published a series of papers dealing with the various constants of sulfuric acid and its role in nitration by ionization of nitric acid. Hughes, Ingold, and coworkers (6) studied the role of nitrous acid in effecting the nitration of phenols and phenolic ethers. Previous results reported in this series of papers indicated that generally the nitration of aromatic compounds by nitric acid in organic solvents is retarded by nitrous acid. However, in the nitration of phenol and aniline and their derivatives a special case arises, such nitration being accelerated by nitrous acid, The authors, t o account for this, advance the theory t h a t the nitrosonium ion (NO+), plays about the same role as the nitronium ion (NOz+)plays in the general mechanism. It appears that the nitrosonium ion leads primarily to nitrosation; and in turn the nitroso compounds are rapidly oxidized to nitro compounds, thereby causing no net loss or gain of nitrous acid. Glazer, Hughes et al. (16)investigated under p a r t VI1 of these papers the products of nitration of aniline derivatives, especially those of dimethylaniline. T h e stages involved in the nitration and concomitant demethylation of dimethylaniline to give N,2,4,6tetranitromethylaniline are analyzed. Consideration is given to the question of how far the various steps require nitrous acid or proceed independently of nitrous acid. Hughes and Jones ($4) under part VI11 studied tbe rearrangements of aromatic N-nitroamines. According to these authors
INDUSTRIAL AND ENGINEERING CHEMISTRY
September 1951
.
two very different types of orientation are involved during the formation of nitro products in the acid-catalyzed rearrangement of phenylnitramine and in the nitration of aniline with nitric acid under comparable conditions. The chemistry of nitronium salts was investigated by Ingold, Goddard, and Hughes (26). Several of these salts were prepared in the pure state, and their assigned ionic constitutions were established spectroscopically. Ingold, Millen, and Poole (26) published a series of articles on the ionization of nitric acid in various acids, and identification of the nitronium ion. Williams and Lovien (39) have investigated the nitration of compounds containing a n activated aromatic nucleus, and they conclude that such compounds may be rapidly nitrated by nitric acid-sulfuric acid-water mixture containing more than 50 mole yo of water, in which the nitronium ion has not been detected spectroscopically. To investigate a compound of this type, they measured the rates of nitration of the trimethyl-ptolylammonium ion in 75 to 82% sulfuric acid between the temperature 17.5" and 45' C. They found that a t 25" C. the rate of nitration rises rapidly in a medium stronger than 80% sulfuric acid and approaches zero at about 75% sulfuric acid. In another paper, Lowen and his coworkers (30) point out that for the nitration of the above compound in 75 to 82% sulfuric acid at 25" C., the nitronium ion is formed in this medium in sufficient concentration to act as a nitrating agent, although it is not present in sufficient amount to be detected by its Raman spectrum. Further evidence for the existence of dissociation in pure nitric acid has been presented by Dunning and Nutt (IS). They determined the freezing point curves of water, nitrogen pentoxide, potassium nitrate, ammonium nitrate, chloric acid, sulfuric acid, and acetyl nitrate in 100% nitric acid. These curves have been related to the self-dissociation of nitric acid, and the data indicate that nitric acid contains about 8 mole % of dissociation products. These authors suggest the presence of the following equilibria:
e HZ0 + NzOs NZ06 eKO; + so, HNOB + HZO eH304 + NO; 2HNO3
and poqsibly 2 HNO,
e HZKO; + NO;
Heertjes and Revallier (21) have investigated some of the properties of nitrating acid consisting of nitric acid and sulfur trioxide. The melting point curve is given of mixtures of nitric acid and sulfur trioxide alm containing water and nitrous acid. In the region investigated three different crystalline compounds were distinguished. One of these was found to be HNOz.2SO1 3 y means of Raman spectra it was proved that all the nitrogen in this compound is in the form NO: and probably all the sulfur is present as HS2O?-. The second compound is believed to be 3HN0,.5S03, but this was not confirmed. The crystals are fine prismatic needles. No definite information could be derived as regards the composition of the third crystalline compound. A discussion and review summarizing the kinetics of nitration have been made by Tomlinson and Groggins (36). These authors point out that a knowledge of kinetics under ahich a nitration reaction is carried out is a valuable tool for establishing the optimum conditions, such ap, the proper propcrtions of reactants, the temperature of reaction, the best Conditions for obtaining the highest yield, the improving of safety, and the evaluation of cost. It has only recently been estzblished that nitric acid behaves aa a base toward sulfuric acid. In strong sulfuric acid, nitric acid ionizes according to the equation: HONOz
+ 2H2S04
KO:
+ H30' + 2HSO;
The reaction giving the nitronium ion presumably takes place
1989
according to the follon4ng equation through protonation of nitric acid.
HO EIOIiOz
+ H+
\
N '=O
/
W HzO
+ NO:
HO They point out also that the function of a dehydrating agent is to react with the water of reaction to yield protophylic (protonattracting) agents, which in turn accelerate the nitration. The dehydrating value of sulfuric acid has been successfully used in the industry for a number of years as a means for controlling operations based on sound research. The dehydrating value of sulfuric acid and the nitric ratio method provide a simple method for process control, and it is related to the optimum combination of NO; with HSO; a t the end of nitration. Its specification assures that the reaction ia completed a t a practical rate, and all nitrations to which it is applied proceed a t useful rates from start to finish. This is believed to be due to the decrease in NO; and the increase in HSOa throughout the reaction.
NITROPARAFFINS Stengel (33) patented a method for the nitration of saturatcd hydrocarbons, such as methane, ethane, propane, n-butane, 2methylpropane, n-pentane, cyclopropane, cyclobutane, cyclohexane, methylcyclohexane, and dimethylcyclohexane. The improved method comprises the control of the reaction tempernture by the introduction of regulated amounts of a gaseous miuture containing free oxygen, so that the temperature of reaction is maintained within the desired range of 390" to 460' C. Stengel's process permits the use of 40 to 70% nitric acid to effect the nitration of the hydrocarbon, as sufficient heat is released by the reaction of the free oxygen with portions of the hydrocarbon to vaporize the nitric acid and to maintain it and the hydrocarbon to be nitrated at the optimum reaction temperature. The nitrating apparatus is also described. A continuous nitration process for the nitration of cyclohexane with nitric acid in the liquid phase is described by Grundmann and Haldenwanger (19). Sitration is carried out by introducing definite proportions of nitric acid (about 35%) and cyclohexane into a cylindrical reaction vessel charged with pecking material, in which the temperature (about 120" to 125" C . preferred) and pressure (about 4 to 5 atmospheres gage) are those required f c r nitration. The resulting products are continuously removed and separated. The unreacted materials are recycled. Maillard and Arbogast ( S I ) describe a process for the nitration of aliphatic chain compounds comprising the introduction of nitric acid in the vapor and liquid phase into a petroleum oil and stearic acid. A review, containing 77 references, covering the manufacturc, purification, properties, and uses of the nitroalkanes and nitroalkenes and their derivatives has been prepared by Von Schickh (36). Tables giving the boiling points and freezing points of the derivatives are included. L I T E R A T U R E CITED (1) Aubertein, P., Mdm. p o u d r e s , 30, 7-42 (1948). (2) I b i d . , pp. 143-50. (3) Bachmann, W. E., Horton, \.Ti. J., Jenner, E. L., MacNaughton, N. W.. and Maxwell. C. E.. 111, J . Am. Chem. SOC..72, 31324 (1950). (4) Boivin, J. L., and Wright, G. F., Can. J . Research, 28, Sect. B, 213-24 (1950). (5) Brissaud, L., MBm. poudres, 30, 205-10 (1948). (6) Bunton, C. A., Hughes, E. D., Ingold, C. K., Jacobs, D. I. H., Jones, M. H., hlinkoff, G. J., and Reed, R. I., J . Chem. SOC., 1950, 2628-56. (7) Clarkson, C. E., Holden, I. G., and Malkin, T., Ibid., 1950, 155662. (8) Colson, R., Me'm. poudres, 30, 43-58 (1948). (9) Crater, W. deC., IND.ESG. CHEM., 40, 1627-35 (1948). (10) Ibid., 41, 1889-92 (1949). (11) I b i d . , 42, 1716-18 (1950).
INDUSTRIAL AND ENGINEERING CHEMISTRY
1990
Dewigne, G., M h . poudres, 30,59-68 (1948). Dunning. W. J., and Nutt, C. W., Trans. Faraday SOC.,47, 15-28 (1951).
Edwards, G., J . Roy. Tech. Coll. (Glasgow), 5, 122-7 (1950). GillesDie. R. J.. Huahes. E. D., and Ingold. C. K., J . Chem. Soc., 1950, 2473-93; 2493-2503; 2532-7; 2 5 3 7 4 2 ; 2542-51.
-
2504-15;
2516-31;
Glazer, J., Hughes, E. D., Ingold, C. K., James, A. T., Jones, C. T., and Roberts, E., Ibid., 1950, 2657-78. Gold, V., Hughes, E. D., and Ingold, C. K., Ibid., 1950,2467-73. Gold, V., Hughes, E. D., Ingold, C. K., and Williams, G. H., I b X , 1950, 2452-66.
Grundmann, C., and Haldenwanger, H., Angew. Chem., 62, 5568 (1950).
Halberstadt, E. S., Hughes, E. D., and Ingold, C. K., J . Chem. SOC.,1950, 2441-52.
Heertjes, P. M., and Revallier, L. J., Research, 3, 286-8 (1950). Hodgson, H. H., Heyworth, F., and Ward, E. R., J . SOC.Dyers Colourtkts, 66, 229-31 (1950).
Hughes, E. D., Ingold, C. K., and Reed, R. I., J . Chem. SOC., 1950, 2400-40.
Hughes, E. D., and Jones, C. T., Ibid., 1950, 2678-84. Ineold. C. K.. Goddard. D. R.. and Hughes. E. D.. Ibid., i9&,2559-$5.
Ingold, C. K., Millen. D. J., and Poole, H. G., Ibid., 1950, 2576s 9 : 2589-2600: 2600-06: 2606-12: 2612-19: 2620-7. (27) Israeiashvili, S., Gature, 165,'No. 4200, 686 (1950).
Vol. 43, No. 9
(28) Jeasup, R. S., and Prosen, E. J., J . Research -Vatl. Bur. Standards, 44,387-93 (1950). Krata, B., Wasser, Vom, 17, 83-8 (1949); C ' h m . d b s . , 44, 8030 (1950). Lowen, A. M., Murray, M. A., and WiIlian~>, G . , J . Chem. SOC., 1950, 3318-22. Maillard, A., and Arbogast, R., Compt. w d , 231, 1237-8 (1950). Rosenthal, A,, and Brown, R. K., Pulp h Paper Mag. Can., 51, No. 6, 99-105 (1950). Stengel, L. A. (to Commercial Solvents C ' O Y ~ . U. ~ . S. Patent 2,512,587 (June 20, 1950). Thinius, K., Chem. Technol., 1, 101-7 (19491: Chem. Abs., 44, 4245 (1950). Todinson, W. R., Jr., and Groggins, P. H., f'h#vt. Eng., 57, No. 12, 131-3 (1950). Von Schickh, O., Angew. Chem., 62, 547-56 !1950). Vroom, A. H., and Winkler, C. A., Can. J . Rr.warch, 28, Sect. B, 701-14 (1950). Watanabe, S., J . SOC.Textile Cellulose I d w t r g , Japan, 1, 63641 (1945); Chem. Abs., 44, 6117 (1950). Williams, G., and Lowen, A. M., J . Chem. Soc., 1950, 3312-18. Willson, F. G., Aguila, F., and Roberta, E. (to Minister of Supply in His Majesty's Government of the U. K. of Great Britain and Northern Ireland), G. S. Patent 2,525,252 (Oct. 10, 1950).
RECEIVED June 13, 1951.
OXIDATION E0c
L. F. MAREK
ARTHUR D. LITTLE, INC., CAMBRIDGE, MASS.
O x i d a t i o n processes, both destructive and constructive, are of enormous importance in industry. Destructive oxidation, evidenced by corrosion of metals, deterioration of paint, rubber, a n d plastics, burning of forests and structures, and the various objectionable effects noted in chemical processing, represents a force to be combatted. Constructive oxidation plays an important role i n the conversion of hydrocarbons to useful chemicals, the transformation of chemical intermediates to more desirable compounds and the controlled utilization of combustion energy. I t represents a force to be directed and controlled for economic purposes. If any area of oxidative processing were to b e singled out for attention, i t would b e that represented by conversion of hydrocarbons to useful organic chemicals both because of the scale of present exploitation and the enormous prospects for the future. Products such as phthalic anhydride, maleic anhydride, ethylene oxide, adipic acid, acrolein, aliphatic aldehydes and acids, certain hydroperoxides, gas mixtures for synthesis of hydrocarbons, oxygenated organic compounds, and ammonia, and others are currently produced by oxidation of hydrocarbons, some on a very large scale. Since there is always room for improvement in yield and reduction of cost, a steady stream of research and development effort i s being poured into this segment of the chemical process industry. Future prospects lie in the adaptation of processing t o new raw materials for products currently made from raw example, oxidation of aromatic hydrocarbons other than materials of limited supply-for naphthalene to phthalic anhydride) oxidation of hydrocarbons for production of chemicals example, oxidation of propylene to acrolein) manufacusually made by other routes-for ture of hydrogen peroxide and other peroxides via hydrogen or hydrocarbon oxidation, formation of ethylene and acetylene from hydrocarbons by oxidative dehydrogenation or autothermal heating) and brand-new areas of development not yet described in the technical literature.
R
EVIEWS of the progress made by petrochemicals in recent
years disclose that upwards of 40% of our organic chemicals production stems from crude oil and natural gas hydrocarbons. Of the primary processes for conversion of hydrocarbons to chemicals @4), oxidation continues to hold a n important place.
ALIPHATIC HYDROCARBONS
chemicals would beerected in Canada. It has also been reported that the corporation will erect a similar plant in the Texas Panhandle to increase its sup;dy of the cheniicals used in manufacture of cellulose acetate. Up to this writing, the McCarthy Chemical Co. plant a t Winnie, Tex., has not been reactivated for use in oxidation of natural gas hydrocarbons, although considerable interest has been shown by various companies in the prospects for conversion of the facility to some process modification that had better earning possibilities. Although the commercial outcome of the major scale Fischer-Tropsch synthesis plant operated by Carthage Hydrocol, Inc., a t Brownsville, Tex., is still uncertain, considerable interest continues to be shown in development of processes for conversion of natural gas hydrocarbons to synthesis gas. One direction taken in such development has been to make use of metal oxides, capable of regeneration by air, as the oxidizing reagent to avoid the need of a n oxygen plant or to avoid the nitrogen dilution introduced when air is used directly. Of course, where the synthesis gas is to be used for ammonia synthesis, introduction of nitrogen dilution is acceptable. Among the met.al oxides that havebeen considered suitable for such a process are the oxides of iron, cobalt, chromium, nickel. molvbdenum. manganese, vanadium, and titanium, alone or in mixtures: Titania is claimed tQ be superior to iron oxides because of less carbon dioxide formation but requires the admixture of certain I
During the year, Celanese Corp. of America announced that a plant based on a process similar to t h a t employed by the corporation at Bishop, Tex., for the air oxidation of propane to a group of
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