Cyclohexylamine and Dicyclohexylamine Cyclohexylamine and dicyclohexylamine, two alicyclic amines which were first described in 1893, are now being produced commercially for the first time in the United States. The physical and chemical properties of the purified amines are summarized. Numerous derivatives of these amines have been prepared and tested for possible uses. Cyclohexylamine, dicyclohexylamine, and their derivatives are finding applications in organic synthesis, as insecticides, plasticizers, corrosion inhibitors, rubber chemicals, dyestuffs, emulsifying agents, drycleaning soaps, acid gas absorbents, and for a variety of miscellaneous uses.
C
YCLOHEXYLAMINE and dicyclohexylamine are alicyclic amines which have been known in the laboratory since 1893, when Baeyer (4) reduced cyclohexanone oxime in absolute alcohol solution to cyclohexylamine by means of metallic sodium. The subsequent history of the product, as described in the literature, is as follows: In 1898 Markownikoff (29) reduced nitrocyclohexane t o cyclohexylamine with zinc dust or with zinc and hydrochloric acid. Sabatier and Senderens (24) in 1905 reduced aniline with hydrogen over a nickel catalyst, reporting as products cyclohexylamine, dicyclohexylamine, and N-phenyl cyclohexylamine. I atieff (18) hydrogenated aniline over nickel oxide in 1908. Zbatier and Mailhe (25) prepared cyclohexylamine and dicyclohexylamine in 1912 by reacting cyclohexanol with ammonia as, using thorium dioxide as a dehydrating agent. In 1919 8kita and Berendt (26) used colloidal platinum as a catalyst and hydrogenated aniline in acetic acid solution, controlling the ratio of cyclohexylamine to dicyclohexylamine by adding hydrochloric acid to the catalyst. Mailhe (21) prepared the amines in 1922 by refluxing hydrazine hydrate and cyclohexanone and hydrogenating the resulting mixture of hydrazones and ketazines. Guyot and Fournier ( 1 1 ) in 1930 hydrogenated phenol over nickel, obtaining cyclohexanol, and then reacted the cyclohexanol with ammonia gas to obtain cyclohexylamineand dicyclohexylamine. Adkins and Cramer (2) in 1930 investigated nickel as a hydrogenation catalyst for aniline and other compounds, with especial regard t o modification of the proportion of simultaneous reactions through control of the conditions of hydrogenation. Adkins, Cramer, and Connor (5)in 1931 studied the effect of hydrogen pressure on aniline hydrogenation over nickel. Diwoky and Adkins (9) studied relative rates of hydrogenation of aniline and other organic compounds and the preferential hydrogenation of two-component mixtures of reducible organic compounds, including aniline. Winans and Adkins (28) studied the alkylation of primary amines during hydrogenation, resulting in the formation of secondary and tertiary amines.
Properties and Uses T. S. CARSWELL AND H. L. MORRILL Monsanto Chemical Company, St. Louis, Mo.
Fractionation of the crude reaction product yields cyclohexylamine, unchanged aniline, and a high-boiling residue containing N-p henyl cyclohexylamine (cyclohexylaniline) a n d dicyclohexylamine. The latter two compounds areiformed by condensation reactions which take place simultaneously with the reduction of the aniline. N-phenyl cyclohexylamine is formed by the condensation of a molecule of cyclohexylamine and a molecule of aniline, splitting out ammonia; dicyclohexylamine is formed by the condensation of two molecules of cyclohexylamine. The equations for these condensations are as follows: CaHiiNHz CsHsNHz ----f C6Hn"CeH6 NHs 2C6HiiNH2 (CsHii)2NH NHa
+
+
+
Further hydrogenation of the N-phenyl cyclohexylamine converts i t quantitatively t o dicyclohexylamine. The ratio of cyclohexylamine to condensation products can be controlled b y careful regulation of the conditions of the reaction. Cyclohexylamine was not commercially produced in the United States until 1936. A number of uses have been found for this highly active compound since that time. It is the purpose of this paper to present the physical and chemical properties of cyclohexylamine and dicyclohexylamine, followed by some suggested applications for these products and their related compounds.
Physical Properties of Cyclohexylamine Cyclohexylamine is a water-white liquid with a strong, fishy, amine odor. The following physical properties were determined in this laboratory upon cyclohexylamine which had been highly purified by several recrystallizations of the hydrochloride, followed by liberation of the free base and refractionation under an atmosphere of nitrogen: B. p. a t 760 mm., C. Crystallizing point C. Sp. gr. a t 25'/25O 'c. Refractive index a t 2 5 O C. Flash point C. Fire point (sustained combustion),
134.6 -17.7 0.8647 1.4565 O
C.
Below 0 30
Cyclohexylamine is completely miscible with water and with all common organic solvents, including alcohols, ethers, ketones, esters, aliphatic hydrocarbons, aromatic hydrocarbons, and chlorinated aliphatic and aromatic hydrocarbons. On distillation in the presence of water, cyclohexylamine forms an azeotropic mixture, boiling at 96.4" C. at 760 mm. and containing 44.2 per cent cyclohexylamine by weight. AddiThe commercial process comprises the catalytic hydrotional data on the boiling point of cyclohexylamine are given, genation of aniline a t elevated temperatures and pressures. in Figure 1and the following table: 1247
INDUSTRIAL AND ENGINEERING CHEMISTRY
1248 Pressure 33. P. Pressure B. P. Mm. H g C. Mm. H g a C. 15 20 25 30
0 0 0 0
30 36 41 45
5 4 3 1
35 40 50 65
0 0 0 0
48 51 56 62
1
4 0 4
Pressure Mm. H Q 100 150 200 300
B. P. C. 72 0
0 0 0 0
Pressure Mm. H Q 400 500 650 760
83 0 90 9 102 5
VOL. 29, NO. 11
B. P. C. 111 6 118 9 127 9 134 5
0 0 0 0
The boiling point and composition of the azeotrope a t reduced pressures are given in Figure 2 and the following table. The composition of the'azeotrope was determined by titration of a sample distilled at each pressure. Pressure Mm. H g 40 70 100 160
B. P. C. 31 7 41.9 49 0 57.3
0 0 0 0
Compn. of Cyclohexylamine Pressure WVt. % Mm. Hg 31 34 35 38
0 0 9 0
200 300 500 760
Compn. of B. P. Cyclohexylamine ' C. Wt. % 63 72 85 96
0 0 0 0
6 7 3 4
39 40 43 44
3 9 0 2
Physical Properties of Dicyclohexylamine Dicyclohexylamine is a water-white liquid with a faint odor resembling that of cyclohexylamine. The following physical properties were determined in this laboratory upon dicyclohexylamine which had been purified by several recrystallizations of the benzoate, followed by liberation of the base and several refractionations under an atmosphere of nitrogen: B. D. at 760 mm.. C. Crystallizing point C. Sp. gr. at 25"/25O %. Refractive in$ex at 25' Flash poiht C Fire point isustained oombustion),
255 8 -0.1 0,9104 1.4823 a
100
C.
160
Dicyclohexylamine is only slightly soluble in water, but is soluble in all common organic solvents and miscible with cyclohexylamine. It does not form an azeotropic mixture on distillation with water. A boiling point-pressure curve at reduced pressures is given in Figure 1 and the following table: Pressure B. P.
Mm. Hg
OC.
0.7 2.9 3.7 6.7
81.8 93.5 99.3 109.7
Pressure B. P. Mm. H g O C. 11.2 25.0 35.0 60.0
120.9 135.4 144.4 154.3
Pressure Mm. H g
B. P.
75.0 100.0 200.0
166.9 174.4 199.0
C.
Pressure Mm. Hg 300.0 500.0 760.0
B. P. C. 214.6 236.2 255.8
Hzt!
t!Hz
When a secondary amine such as N-ethyl cyclohexylamine is reacted with 2,Z'-dichlorethyl ether, one would expect to obtain a disubstituted ether, which would have the structure: CzHr--N-CH&H2-O-CH2CH2-N-C2Hb
AH
However, t h e only identifiable products from the reaction are N-cyclohexyl morpholine and the corresponding disubstituted cyclohexylamine. The mechanism of this reaction is not clear, but it is possible that the first product is a monosubstitution product of the ether with the following structure:
.........................................
............................
I C~HGLN-CH~CH~-O-CH~CH I :. . . . . ..: I .......
Chemical Properties of Cyclohexylamine Cyclohexylamine is a strong base; it is surpassed in this respect only by piperidine and its derivatives and some of the higher alkyl and dialkyl amines, as shown by Hall and Sprinkle ( l a ) . It is stronger than ammonia and the ethanolamines. Cyclohexylamine forms salts with all acids, including carbon dioxide which is absorbed rapidly from the air. It reacts with long-chain fatty acids to form soaps. The nitrogen atom is extremely reactive and will combine readily with organic compounds containing an active halogen atom, with acid anhydrides, or with alkylene oxides to form the corresponding N-substituted cyclohexylamines. One or both hydrogen atoms on the nitrogen may be replaced in this manner by alkyl, axblkyl, acyl, or alkyl01 groups (16). With carbon disulfide] cyclohexylamine undergoes the usual reaction of aliphatic amines to form dithiocarbamates. Cyclohexylamine reacts with aldehydes similarly to aniline, forming with the higher aldehydes alkylidene compounds with a double bond on the nitrogen, and with formaldehyde, a heterocyclic compound similar to anhydroformaldehyde ani-< line. In addition to these expected reactions of cyclohexylamine, the reaction of cyclohexylamine and certain of its derivatives with 2,2'-dichlorethyl ether should be mentioned because of the unusual course taken by this reaction. 2,2'-Dichlorethyl ether reacts with cyclohexylamine to form N-cyclohexyl morpholine, in which the ether group forms a heterocyclic ring on the cyclohexylaminenitrogen as follows:
By splitting out ethyl chloride as shown by the dotted lines, the ring is closed at the nitrogen to form the morpholine, and the ethyl chloride reacts with another molecule of N-ethyl cyclohexylamine to form N-diethyl cyclohexylamine. The same reaction has been observed with N-benzyl cyclohexylamine, the products being the morpholine and N-dibenzyl cyclohexylamine. Cyclohexylamine attacks all copper alloys and lead. When cold it has no effect on aluminum, nickel, or tin. Hot cyclohexylamine attacks aluminum very slowly. There is no effect on iron, although iron which has not previously been in contact with cyclohexylaminewill discolor it.
Chemical Properties of Dicyclohexylarnine Dicyclohexylamine is a strong base. It is slightly more basic than cyclohexylamine, but it is so water insoluble that only a very dilute solution can be made. By dissolving 0.01 equivalent of cyclohexylamine and dicyclohexylamine in ethanol, half neutralizing each with hydrochloric acid, and determining the p H of the resulting solutions, it is possible to compare the two bases. The experimental p H values were as follows : Cyclohexylamine Dicyclohexylamine
Glass Electrode
Antimony Electrode
10.30 10.40
9.60 9.75
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INDUSTRIAL AND ENGINEERING CHEMISTRY
From these results it was concluded t i a t dicyclohexylamine is approximately 0.1 p H unit more basic than cyclohexylamine. The reactions of dicyclohexylamine are similar to those of cyclohexylamine except that only monosubstitution products can be formed. It forms salts with all acids and soaps with fatty acids. N-substituted derivatives can be prepared as with cyclohexylamine. Dicyclohexylamine differs from cyclohexylamine in that it forms crystalline hydrates and alcoholates at low temperatures.
1249
Dicyclohexylamine is more toxic than cyclohexylamine. After injection in olive oil, symptoms appear sooner, and the rabbit has convulsions ending in death if the dose is one gram. A half-gram is just sublethal, causing convulsions and temporary paralysis of the hindquarters. Dicyclohexylamine is also absorbed through the skin, unlike cyclohexylamine, and will cause death if the amount is large. Dicyclohexylamine, like cyclohexylamine, will cause a dermatitis if left on the skin.
Uses Methods of Analysis Cyclohexylamine and dicyclohexylamine are analyzed by indirect titration with standard hydrochloric acid. Samples of the amines weighed by difference from dropper weighing bottles are dissolved in excess acid, and the excess is determined by back-titration with standard sodium hydroxide to a bromothymol blue end point. This procedure prevents absorption of carbon dioxide from the air during the titration, as would be the case if the amines were titrated directly with acid. The end point may be determined using either a bromothymol blue indicator or a potentiometric method. The end point is very sharp in either case. The indicator method is to be preferred, however, because of its simplicity. A modification is necessary in the case of dicyclohexylamine because of the low solubility of its hydrochloride. Sufficient alcohol must be added to the standard acid before the sample of dicyclohexylamine is weighed into it to keep the hydrochloride in solution. Using 50 cc. of 0.5 N hydrochloric acid, a 2-gram sample of dicyclohexylamine will require aboutr 70 cc. of alcohol (methanol or ethanol).
Toxicity Data Toxicity data on cyclohexylamine and dicyclohexylamine were determined by F. B. Flinn of Columbia University. His report includes the following data : Cyclohexylamineis quite caustic and will produce a dermatitis if left on the skin for any length of time. It should therefore be washed off immediately, although it is not absorbed through the skin in lethal quantities. When injected in olive oil, the lethal dose to rabbits, weighing 2 kg. on the average, is 1 gram. Cyclohexylamine is a convulsant poison, acting on the motor centers of the spinal column and medulla. I n lethal doses it results in the death of the animal in 3 to 4 hours. The effects are slow in beginning, and the first symptoms may not appear for several hours after the injection. Smaller doses up to 0.5 gram have no apparent ill effects even when repeated daily for 10 days. Cyclohexylamine was also fed to rabbits, guinea pigs, and rats in sublethal doses in water solution. The daily dosage was 100 mg. per kg. of body weight. The rabbits weighed, on an average, 2 kg; the guinea pigs 500 to 600 grams, and the rats 250 grams. The dosage was therefore 200 mg. for the rabbits, 50 to 60 mg. for the guinea pigs, and 25 mg. for the rats. The animals were fed these amounts of cyclohexylamine daily for 82 days, thus receiving total doses of 16.4,4.1 to 4.9, and 2.1 grams, respectively. One rabbit and one guinea pig died during this period, but the cause of death was shown by an,autopsy to be pneumonia. Each of the animals gained weight during the period of the test. At the end of the test all the animals were killed and autopsied. I n each case the autopsy showed normal conditions of all the internal organs, with no sign of irritation. It was also noted that cyclohexylamine in these amounts made water taste so bitter that no human being would drink it, and consequently the danger of accidental intake of cyclohexylamine would seem to be slight.
The reactivity of the amine group in cyclohexylamineand dicyclohexylaminehas been noted. It naturally follows that an important use of these compounds is in the synthesis of derivatives. A rather complete list of derivatives has been prepared in this laboratory; some were previously described in the literature and some are new. The list is too lengthy to reproduce in full, but those derivatives which have shown promise in various applications will be mentioned. INSECTICIDES. A study of the patent literature, together with preliminary insecticidal tests on cyclohexylaminederivatives, indicated that these compounds possessed some merit. An exhaustive study of the derivatives of cyclohexylamine and dicyclohexylamine was begun in 1935 at Urbana, Ill., under a Crop Protection Institute Fellowship. The work included both laboratory tests and field tests, and was conducted by C. W. Kearns under the direction of W. P. Flint, state entomologist. The object of the study was to choose from the large number of derivatives which were tested, those which combined high toxicity to insects with a wide margin of safety to plants and foliage. The work soon narrowed down to the N,N-alkylacyl cyclohexylamines. The amyl group was chosen as the best alkyl group from the standpoint of both toxicity and manufacturing cost. Having fixed the alkyl group, the acyl group was varied from formyl
FIGURE1. BOILINGPOINTSOF CYCLOHEXYLAMINE AND DICYCLOHEXYLAMINE AT VARIOUS PRESSURES through acetyl, propionyl, butyryl, benzoyl, phthalyl, ptoluene sulfonyl, and stearyl. This study led to the choice of N,N-amylacetyl cyclohexylamine and N,N-amylbenzoyl cyclohexylamineas the best insecticides for use against aphids and the greenhouse red spider (19). Kearns and Flint (20) reported after further work that these compounds were exceptionally effective against apple and grape leaf hoppers and against thrips. The benzoyl compound was about 25 per cent more toxic to insects than the acetyl derivative and a t the same time was safer to plants. The plant safety factor, however, was still not large enough to allow the safe use of
INDUSTRIAL AND ENGINEERING CHEMISTRY
1250
sufficiently high concentrations to effect satisfactory control of red spider on certain greenhouse crops. A study of the relationship of molecular structure to plant injury led to the belief that the carbonyl group of the acyl radical was causing the injury. N-alkyl cyclohexylamines were safe on plants, although insufficiently toxic to insects, and the injury experienced with N,N-allrylacyl derivatives seemed to decrease as the acyl group became larger (and the carbonyl group correspondingly less significant in the molecule). Accordingly, derivatives of N-amyl cyclohexylamine were prepared in which the acyl group was replaced by hydrocarbon radicals. Although the work in this field is not
VOL. 29, NO. 11
N-p-toluenesulfonyl cyclohexylamine is at present on the market under the trade name of Santicizer 1-H as a lightstable, nontoxic, solid plasticizer imparting moisture resistance to nitrocellulose and acetyl cellulose compositions. N,N'-diacetyldicyclohexyl ethylenediamine is prepared from cyclohexylamine and ethylene dichloride; this product is then acetylated to form the disubstituted amine which is light stable and a good plasticizer in nitrocellulose, Cyclohexylamine and monosubstituted cyclohexylamines such as N-ethyl cyclohexylamine and dicyclohexylamine can be used to replace hexamethylene tetramine as a hardening agent for soybean molding powders; the residual amine serves as a plasticizing agent in the final product. Cyclohexylamine can also be used as a condensing agent for the original phenol-formaldehyde-soybean meal reaction in place of ammonia. It is considerably more effective than ammonia as a condensing agent for these one-step, thermosetting, phenolic resins. CORROSION INHIBITORS. Cyclohexylamine and soap mixtures are effective inhibitors of ferrous corrosion in automobile radiator alcohol solutions (27). An uninhibited 50 ' per cent alcohol solution will rust steel wool when heated a t reflux for 2 to 3 hours. When 0.1 per cent cyclohexylamine plus 0.3 per cent soap based on the alcohol are added, the ,' steel wool remains bright for 60 to 200 days. Dicyclohexylamine, mixtures of cyclohexylamine and dicyclohexylamine, or N-ethyl cyclohexylamine, all in admixture with soap, are also effective. Cyclohexylamine alone or soap alone has some corrosion inhibiting value, but the mixture is far superior to either constituent. This mixture has given satisfactory commercial use for several years, and no damage to the metal I 1 parts of the engine has been noted during that time. zh PRESSU.Q€- m m Of H j RUBBER CHEMICALS. According to the patent literature, the cyclohexylamine, dicyclohexylamine,and N-alkyl cyclohexylFICXJRE 2. BOILINGPOINTAND COMPOSITION OF QYCLOHEXYLAMINE-WATER AZEOTROPEAT VARIOUSPRESSURES amine salts of the mercaptoaryl thiazoles are good vulcanization accelerators (7, 25), giving compounds of great tensile strength, elasticity, and durability. Other compounds of complete, Compton and Kearns (6) reported that one of these cyclohexylamine, dicyclohexylamine, and their derivatives modified products is more toxic to red spider and possesses a with sulfur-containing organic materials are also good acgreater margin of safety to plants than any of the acylated celerators or activators for other organic accelerators. derivatives. Field tests have so far confirmed the laboratory DYESTUFFS.Substituted N-phenyl cyclohexylamines conresults and indicate that this material is superior to any now taining one or two nitro, amino, or sulfonic acid groups on the on the market for control of these common greenhouse and phenyl ring are mentioned in the patent literature as dye orchard tests. intermediates and dyestuffs (14, 17). A blue to blue-green Comparison of the insecticidal properties of the rather light-fast wool dye can be prepared from anthraquinone and complete list of derivatives which have been prepared has cyclohexylamine (16);the dyestuff should be applied in the enabled Kearns and Flint (19) to deduce relationships bepresence of cyclohexylamine or N-alkyl cyclohexylamines. tween molecular structure and toxicity to insects. ConCYCLOHEXYLAMINE SOAPS. Cyclohexylamine and dicycloto be a basic toxic radical, the subsidering ammonia ("8) hexylamine soaps are good emulsifying agents. Cyclohexylstitution of one of its hydrogen atoms with a cyclohexyl group amine oleate can be used when a large amount of oil is to be to form cyclohexylamine results in a primary amine more emulsified in a small amount of water, as in insecticidal uses toxic than most primary aliphatic and aromatic amines. N where kerosene containing a toxic ingredient such as pyrethalkylation of cyplohexylamine produces even more toxic comrum extract is to be emulsified with water for application pounds, the toxicity increasing with the length of the alkyl in mosquito control. It has the advantage of compatibility chain. Acyl or hydrocarbon groups substituted for the third with pyrethrum extract in oil. Cyclohexylamine stearate is and last hydrogen atom again increase toxicity markedly. not suitable for emulsifying oils of this type but can be used It should be mentioned that N-cyclohexyl morpholine has a with waxes. marked anesthetic effect on insects. Insects sprayed with Cyclohexylaminecan be used as such or in the form of soaps this material are completely paralyzed and remain quiescent with fatty acids, resin acids, or naphthenic acids as wettingfor 3 hours, following which they recover co out, cleansing, washing, emulsifying, or dispersing agents in no apparent ill effects. textile dyeing, steeping, scouring, or mercerization baths (8). Cyclohexylamine.and its derivatives in combination with Cyclohexylamine or dicyclohexylamine stearate can be cresylic acid in petroleum oil have been used as a bedbug used as dry-cleaning soai)s, since they are oil soluble. The spray, having the advantage of freedom from odor and high latter is preferable, since, when the solvent is distilled, CYkilling power. The lower N-alkyl cyclohexylamines are clohexylamine stearate decomposes and allows free cyclotoxic to the American roach in the form of a 5 per cent dust. hexylamine to distill over with the recovered solvent. DicyPLASTICIZERS. The N,N-alkylacyl cyclohexylamineshave clohexylamine, having a higher boiling point, w ill not distill shown promise as plasticizers for cellulose esters, phenolic over under these conditions. resins, soybean resins, vinyl resins, and alkyd resins.
'
4 ,L
L
L L II I
\ 1 ~
NOVEMBER, 1937
,
INDUSTRIAL AND ENGINEERIYG CHEMISTRY
MISCELLANEOUS USES.Other uses mentioned in the literature for cyclohexylamine, dicyclohexylamine, or their derivatives include absorption of acidic gases such as carbon dioxide, hydrogen sulfide, and sulfur dioxide, preservation of latex (IS),plasticization of casein (la), prevention of static charge on cellulose derivatives ( I ) , neutralization of plant and insect poisons (IO),and use as a solvent for dyestuffs in the printing and dyeing industry (6).
Literature Cited (1) Aceta G. m. b. H., French Patent 689,984(1931). (2) Adkins, H.,and Cramer, H. I., S.Am. Chem. SOC.,52,4349-58 (1930). (3) Adkina, H., Cramer, H. I., and Connor, R., Ibid., 53, 1402-5 (1931). 14) Baeyer, A., Ann., 278, 103 (1893). (5) Chemical Age (London), Feb. 20, 1937,166. (6) Compton, C. C., and Kearns, C. W., J . Econ. Entomot., 30 (3), 512-21 (1937). (7) Cramer, H.I. (to Goodyear Tire and Rubber Co.), Canadian Patents 357,049and 361,541 (1936). (8) Deutsche Hydrierwerke A.-G., British Patent 413,357 (1934). (9) Diwoky, F. F., and Adkins, H., J . Am. Chem. SOC.,53, 1868-75 (1931). (10) Graves, G. D., U. S. Patent 1,913,631(1933). (11) Guyot, A., and Fournier, M., Bull. SOC. chim., 47, 203-10 (1930).
1251
(12) Hall, N. F., and Sprinkle, M. R., S.Am. Chem. SOC., 54,3469-86 (1932). (13) I. G.Farbenindustrie A.-G., British Patent 271,863 (1927). (14) I. G. Farbenindustrie A.-G., Ibid., 340,495 (1929); German Patent 507,831 (1928); French Patent 684,417 (1929); U.S . Patent 1,836,295(1931). (15) I. G. Farbenindustrie A.-G., French Patent 032,490(1927). (16) I. G. Farbenindustrie A.-G., German Patent 482,930 (1926); French Patent 638,023(1928); British Patent 297,484(1928); U.S. Patent 1,775,175(1930). (17) I. G. Farbenindustrie A.-G., German Patent 512,404 (1928); U. S. Patent 1,944,514(1934). (18) Ipatieff, V.,Ber., 41, 991-3 (1908). (19) Kearns, C. W., and Flint, W. P., J . Econ. Entomol., 30 (I), 158-66 (1937). (20) Kearns, C. W., and Flint, W. P., private communication. (21) Mailhe, A,, Compt. rend., 174, 465-7 (1922). (22) Markownikoff, W., Ann., 302, 22 (1898). (23) Sabatier, P., and Mailhe, A,, Compt. rend., 153, 1204-8 (1912). (24) Sabatier, P.,and Senderens, J. B., Ibid., 138,457 (1905). (25) Sebrell, L. B. (to Wingfoot Corp.), U. 8. Patents 2,050,195and 2,050,199(1936). (26) Skita, A., and Berendt, W., Ber., 52, 1519-35 (1919). (27) Taylor, M. H. (to Merrimac Chemical Co.), U. S. Patent 2,060,138(1936). (28) Winans, C. F., and Adkina, H., J . Am. Chem. Soc., 54, 306-12 (1932). RECEIVED September 8, 1937.
Presented before the Division of Industrial and Engineering Chemistry a t the 94th Meeting of the American Chemical Society, Rochester, N. Y . , September 6 to 10, 1937.
Welded Equipment in the Gas Industry C. V. MIDDAUGH The Koppers Company, Western Gas Division, Fort Wayne, Ind.
Illustrations on two following pages presented thr'ough courtesy of The Koppers Company.
APID adoption of welding (both electrical and acetylene) by the gas industry has followed the development of technic and of designs of equipment to utilize this method of equipment fabrication. The story of the development and the results effected by it are best illustrated by the photographs on the two following pages. These show more graphically than description could, the contrast between old methods of fabrication and modern welding practice. One of the very difficult as well as expensive pieces of apparatus fabricated today is the large coke-oven collecting main. This main requires considerable layout along with the incorporation of many irregular steel castings in its design. During the past few years the design of this main has been radically changed, resulting in the present type of collecting main. This design utilizes all welded parts wherever possible, and clumsy steel castings have been replaced with welded steel plate. An illustration of this is the heavy cast-steel offtake tee of former years which is now supplanted with the modern design made of arc-welded steel plates. One of the most important advantages of welding over riveted construction is that a welded joint will remain wateror gas-tight indefinitely; with riveted joints, on the other hand, the continual use or vibration of the equipment often jars the rivets loosgt% the extent that the seam must be tool-caulked. Since the advent of welding, many small purifiers, gas holders, and small water-gas sets are completely fabricated in the shops and then shipped, ready to be set on the foundation. As a result of the progress that welding has made during the past few years and the popularity that it is rapidly gaining, within only a few years riveted construction will undoubtedly be almost entirely replaced by all-welded structures.
R
RECEIVBD August 30, 1937.
