THE SEPARATION OF THE ISOMERIC DINITRO-1,4

May 1, 2002 - C. J. SUNDE, GESTUR JOHNSON, and C. F. KADE. J. Org. Chem. , 1939, 04 (5), pp 548–554. DOI: 10.1021/jo01217a004. Publication Date: ...
1 downloads 0 Views 486KB Size
Download PDF
[CONTRIBUTION FROM THE SCHOOL OF CHEMICAL TECHNOLOGY OF TEE NORTH DAKOTA AGRICULTURAL COLLEGE]

THE SEPARATION OF THE ISOMERIC DINITRO-1,4-DIBROMOBENZENES AND THEIR REACTIONS WITH p-PHENYLENEDIAMINE* C. J. SUNDE, GESTUR JOHNSON,

AND

C. F. KADE

Received M a y 89, 19S9

1,CDibromobenzene, when treated with fuming nitric acid and concentrated sulfuric acid, gives a mixture of isomeric dinitro-1 ,4-dibromobenzenes. Austenl isolated two of these isomers and showed that the structure of the one melting a t 120" is 1,4dibrom0-2,6-dinitrobenzene, but later reported a melting point of 99-100" for this compound2. Calhane and Wheeler3 determined the structure of Austen's second isomer (m.p. 159") to be 1,4dibrom0-2,3-dinitrobenzene. Later, Jackson and Calhane4 isolated the third isomer (m.p. 127") and proved that it has the structure: 1,4-dibrom0-2,5-dinitrobenzene. Heller and Meyer6, using Austen's method, were unable to isolate 1,4-dibromo-2, gdinitrobenzene, or even to obtain evidence of its existence in the reaction mixture obtained on nitrating pdibromobenzene. In the present study it was found very difficult, using Austen's procedure, to obtain 1,4-dibromo-2,6-dinitrobenzenein sufficient quantity to study its reaction with p-phenylenediamine. As a result the method of separation has been simplified and improved so as to increase the yield of 1,4-dibrom0-2,6-dinitrobenzene from a "small amount" to a yield of 7.1 per cent., and to double the yield of 1,4-dibrom0-2,5-dinitrobenzene. Dioxan proved to be a good solvent for obtaining the 2,sdinitro compound. No 1,4-dibromo-2,6-dinitrobenzenehaving a melting point of 99-100" could be obtained. There was no change after a melting point of 119-120' was reached on crystallizing from carbon disulfide, acetic acid, or alcohol. To check further the purity of the 119-120" melting material a small amount was treated with an equal weight of potassium nitrite in dilute alcohol according to the procedure of Busten*

* This paper is taken in part from theses submitted in partial fulfilment of the M.S. degree by Gestur Johnson and C. F. Kade. 1 AUSTEN, Ber., 8, 1182-1184 (1875);ibid., 9, 621-623, 918-921 (1876). * AUSTEN,Am. J . Sei. (Silliman'a), [a]16, 46 (1878). * CALHANE AND WHEELER, Am. Chem. J . , 22, 449-458 (1899). 4 JACKSON AND CALHANE, ibid., 28, 451-474 (1902). HELLER AND MEYER, J . prakt. Chem., [2], 72, 197-200 (1905). 518

SEPARATION O F DINITRO-1,4-DIBROMOBENZENES

549

with the result that a 98 per cent. yield of 4-bromo-2,6dinitrophenolwas obtained. P-PHENYLENEDIAMLNE 1,4-Dibromo-2 ,3-dinitrobenzene does not react with p-phenylenediamine when an alcoholic solution containing sodium acetate is refluxed according to the method of Nietzki and Ernst6. When refluxed with an equivalent quantity of p-phenylenediamine in alcohol solution in the presence of copper bronze, potassium iodide and potassium carbonate, according to the method of Irma Goldberg’ 1,4-dibromo-2 ,3-dinitrobenzene reacts to give 3 ,6-dibromo-2-nitroanisole. The same product is obtained by omitting the p-phenylenediamine in the above reaction mixture. 3 ,6-Dibromo-2-nitroanisole was also prepared according to the method of Jackson and Calhane4 for the preparation of the phenetole. However, when 1,4dibromo-2,3dinitrobenzeneis treated with an excess of p-phenylenediamine in alcohol solution according to the procedure of Goldberg, 3 6dibromo-2-nitro4 ’-aminodiphenylamine is formed. Here also the bromine does not react, but a nitro group is replaced. 1,4-Dibromo-2 5dinitrobenzene reacts with an equivalent quantity of p-phenylenediamine in alcohol solution containing sodium acetate to give 4.-bromo-2 5dinitro-4’-aminodiphenylamine, with the loss of a molecule of hydrogen bromide. It was found impossible, however, to replace the second bromine atom. 4-Bromo-2 5-dinitro4‘-aminodiphenylamine reacts with excess p-phenylenediamine in alcohol solution containing copper bronze, potassium iodide, and potassium carbonate to give the Bandrowski base. This is analogous to Crippa’s* method of preparing the Bandrowski base by the oxidation of p-phenylenediamine with nitrobenzene. An alcohol solution of the acetyl derivative of 4-bromo-2 ,5dinitro-4’aminodiphenylamine with excess p-phenylenediamine refluxed for seven hours gives a red crystalline substance that is not readily purified. A condensation reaction takes place, but a nitro group, and not the bromine atom, is replaced. No attempt has as yet been made to determine which nitro group is replaced. 1,4-Dibromo-2 6-dinitrobenzene reacts very readily with p-phenylenediamine. In alcohol solution with excess p-phenylenediamine and sodium acetate a greenish-black crystalline compound, 4-bromo-2 ,6-dinitro-4’aminodiphenylamine melting at 193-194’, is obtained in a quantitative yield. If, however, two moles of 1,4dibrom0-2,6dinitrobenzene and REACTIONS WITH

)

)

)

)

)

NIETZKI AND ERNST,Ber., 23, 1852-1856 (1890). GOLDBERG, ibid., 40,45414546 (1907). 8 CRIPPA, BELLANI, AND MARUBINI, Gam. chim. ital., 80, 644 (1930). e

7

550

C. J. SUNDE, G. JOHNSON AND C. F. KADE

one mole of p-phenylenediamine are condensed a dark-red product melting at 276-277' after one crystallization from glacial acetic acid is obtained. The same N ,N'-bis-(2 ,6-dinitro-4-bromophenyl)-p-phenylenediamineis obtained by condensing 4-bromo-2,6-dinitro-4 '-aminodiphenylamine with 1,4-dibromo-2 ,6dinitrobenzene. In the formation of both of the above condensation products the bromine atom flanked by nitro groups in both ortho positions is replaced. The other bromine atom does not react. Neither does it react when 4-bromo2,6dinitro4'-arninodiphenylamine is acetylated and the acetyl derivative is treated with p-phenylenediamine in alcohol solution according to the method of Nietzki and ErnstBor that of Goldberg'. In both cases unchanged starting material was recovered. The N , N'-bis-(2, 6-dinitro-4-bromophenyl)-p-phenylenediamine,prepared by the condensation of 1 ,4dibromo-2 ,6dinitrobenzene is identical with the N ,N'-bis-(2,6-dinitro-4-bromophenyl)-p-phenylenediamine prepared from l-chloro-4-bromo-2,6-dinitrobenzeneand p-phenylenediamine according to the method of Joshi and Saneg, as shown by melting points and mixture melting points. Joshi and Sane reported a melting point for their product of over 300". In the present study a melting point of 276-277' was obtained after one crystallization from glacial acetic acid, and this melting point did not change after four more crystallizations alternately from nitrobenzene and glacial acetic acid. EXPERIMENTAL

Nitration of p-dibromobenzene and separation of 1,4-dibromo-.%?,S-dinitrobenzene.Two hundred grams of p-dibromobenzene (Eastman Kodak Co.) was nitrated according to the directions of Jackson and Calhane.* The reaction product was poured on cracked ice, and after a few minutes the oil solidified. It was allowed to stand overnight, filtered, washed thoroughly with water, and dried. A yield of approximately 250 g. was obtained. The product was dissolved in 425 ml. of hot glacial acetic acid and allowed t o stand in a cool place overnight. The crystals which formed were removed by filtration, and the filtrate was concentrated by removing about 100 ml. of acid by vacuum distillation. The solution was again allowed t o stand overnight, when a second crop of crystals was obtained. Another 100 ml. of acid was removed by distillation under reduced pressure, and after standing overnight a third crop of crystals was obtained. The three crops of crystalline material were combined giving a total yield of 35 g. of product melting at 98-145". After two crystallizations from glacial acetic acid the substance melted at 159-160" (Austen, 159"). It was necessary t o remove at least 35 g. of crude 1,4-dibromo-2,3-dinitrobenzene at this point in order t o prevent its appearance after most of the 1,4dibromo-2,5-dinitrobenzenehad been removed. Separation of 1,4-dibromo-f?,Cdinitrobenzene.-To the filtrate from the third crop of l,4-dibromo-2,3-dinitrobenzene800 ml. of water was added. A yellow oil, which 9

JOSHIAND SANE,J . Ind. Chem. SOC.,10,459-463 (1933).

SEPARATION OF DINITRO-1,4-DIBROMOBENZENES

551

solidified on cooling, separated. This was filtered, washed repeatedly with water, and dried. The solid was broken into small pieces and washed thoroughly with water by decantation. The dried material, 200-215 g., was dissolved in 500 ml. hot dioxan. After standing overnight the crystals which had formed were removed by filtration, and the filtrate was concentrated by removing 160 ml. dioxan by distillation under reduced pressure. A second crop of crystals was obtained, and another 150 ml. of dioxan was removed by vacuum distillation. On standing, a third crop of crystals formed, and was combined with the two previous crops. The total yield of crude 1,4-dibromo-2,5-dinitrobenzene(m.p. 68-104") averaged 66 g. After two crystallizations from hot alcohol 30-35 g. of material, m.p. 126-127", was obtained. (Jackson and Calhane, 127"). Separation of 1,4-dibromo-2,6-dinitrobenzene.-Thedioxan filtrate after removal of the third crop of 1,4-dibrom0-2,5-dinitrobenzenewas concentrated by the removal of about 100 ml. of solvent under reduced pressure. On standing a precipitate was obtained, giving 30 g. of material, m.p. 70-80". After five crystallizations from alcohol 16 g. of material melting at 119-120" was obtained. The filtrate was brought to a syrupy consistency under reduced pressure and transferred to a beaker from which the residual dioxan was evaporated by heating on a steam plate for a few days. The oily liquid solidified on cooling. The solid was dissolved in 90-125 ml. of carbon disulfide, from which on cooling 10-15 g. of material, melting a t 93-114", was obtained. This gave, after two crystallizations, 5.5-8 g. of product, m.p. 119-120". There was no change in the melting point on further crystallizations from either glacial acetic acid, alcohol, or carbon disulfide. Conversion of 1,4-dibromo-d,G-dinitrobenzene to the phenol.-A mixture of 0.5 g. of material (m.p. 119-120"), 8 ml. of alcohol, 0.5 g. of potassium nitrite and 4 ml. of water was heated on a steam bath until all solid material was in solution. On cooling, a mass of red crystals formed. After standing overnight, 12N hydrochloric was added until the mixture was acid. On heating and shaking, the red crystals dissolved, giving a yellow solution. This was cooled in an ice-salt mixture, giving a yellow crystalline substance. A yield of 0.395 g. (98% of the theoretical) was obtained, m.p. 73-74". After one crystallization from alcohol or water, m.p. 74-75". (Austen, 71'; Fromm and Ebert, 78"). This phenol is identical with the phenol obtained by brominating (Eastman Kodak Co.) 2,6-dinitrophenol according to the method of Fromm and Ebert,lo as shown by m.p. and mixture m.p. Reactions of the Dinitro-1 ,4-Dibromobenzenes with p-Phenylenediamine

A . Reactions of 1,.6-dibromo-S,8-dinitrobenzene.(a) Preparation of 8,G-dibromo2-nitroanisole.-An equimolar mixture of 1,4-dibromo-2,3-dinitrobenzene(1 g.) and p-phenylenediamine (0.330 g.) was refluxed for two hours with 0.44 g. of potassium carbonate, 0.10 g. of potassium iodide and 0.05 g. of copper bronze in 40 ml. of methyl alcohol. The mixture was filtered while hot and 100 ml. of water added t o the filtrate. The product was crystallized three times from methyl alcohol with the aid of a little Norite. A colorless, crystalline substance melting a t 82.5-83' was obtained. The yield was 5% of the theoretical. The same product was obtained without the presence of p-phenylenediamine in the above reaction as shown by a mixture melting point. 3,6-Dibromo-2-nitroanisole(m.p. 82.5-83", mixture m.p. with material from the above reaction 82.5-83") was also prepared by the action of sodium methoxide on lf4-dibromo-2, 3-dinitrobenzene in benzene solution according 10

FROMM AND EBERT, J . p d t . Chem., 108,75-87 (1924).

552

C. J. SUNDE, G. JOHNSON AND C. F. KADE

to the method of Jackson and Calhane4 for the preparation of the corresponding phenetole. AnaE. Calc'd for CrHsBrZNO,: N, 4.50;Br, 51.44; mol. wt., 311. Found: N, 4.56;Br, 51.46; mol. wt. (Rast camphor method), 306. ( b ) Preparation of J,6-dibromo-6-nitro-4'-am~nodiphenylamine.-A mixture of 1 g. of 1 ,4-dibromo-2,3-dinitrobenzene, 3 g. (excess) of p-phenylenediamine, 0.44 g. of anhydrous potassium carbonate, 0.10 g. of potassium iodide and 0.05 g. of copper bronze was refluxed for five or six minutes. The reaction mixture was filtered hot and to the filtrate was added 100 ml. of water. A chocolate-brown product precipitated, and was purified by crystallization from methyl alcohol with the aid of Norite. After one crystallization i t melted at 146-147". There was no change in m.p. on further crystallizations. Anal. Calc'd for C l ~ H ~ B r & a O zC,: 37.20;H, 2.34; mol. wt., 387. Found: C, 37.04;H, 2.19; mol. wt. (Raat camphor method), 365. B. Reactions of 1,4-dibromo-6,b-dinitrobenzene.(a) Preparation of 4-bromo6,b-dinitro-~'-aminodiphenyEamine.-To 1 g. of the dibromodinitrobenzene and 0.330 g. of p-phenylenediamine dissolved in 40 ml. of alcohol was added 0.1 g. of sodium acetate, and the mixture was refluxed for one hour on a steam bath. The colorless reaction mixture soon developed a characteristic dark red color which gradually deepened. The reaction mixture on addition of water and cooling gave a dark-brown crystalline product. The residue, after filtration, was dissolved in hot alcohol, a little Norite was added, and after a few minutes the suspension was filtered. A few ml. of water was added to the filtrate, and on standing a small amount of an amorphous dark-brown solid precipitated. This was removed by filtration, and more water was added to the filtrate. Crystals formed immediately and more water was added t o complete the precipitation. Three-tenths of a gram of a dark-blue crystalline substance melting a t 167-170" was obtained after one crystallization from dilute alcohol. After being recrystallized twice from dilute alcohol, once from chloroform, and finally from 95% alcohol i t melted a t 180-181°. There was no change in m.p. on further crystallizations. The substance is sparingly soluble in alcohol, soluble in chloroform but insoluble in petroleum ether (b.p. 30-60'). Anal. Calc'd for CleHoBrN404: C, 40.79; H, 2.57. Found: C, 40.99; H, 3.02. The acetyl derivative, a dark-red substance, prepared in the usual manner, was crystallized once from dilute alcohol, and once from 95% alcohol, m.p. 227-228'. Anal. Calc'd for C14HlrBrNd06:C, 42.53; R, 2.80. Found: C, 42.31; H, 2.73. (a) 1. Attempted condensation of 4-bromo-d,b-dinitro-4'-aminodiphenylaminewith p-phenylenediamine.-Five-tenths of a gram of the substituted diphenylamine and 2 g. (excess) of p-phenylenediamine were dissolved in 40 ml. of alcohol. One-tenth of a gram of copper bronze, 0.2 g. of potassium iodide and 0.2 g. of anhydrous potassium carbonate were added, and the mixture was refluxed for eighteen hours on a steam bath. The hot reaction mixture was filtered, and, on cooling, a dark-red precipitate formed, (m.p. 235-237"). The crude reaction product was acetylated b y heating with excess acetic anhydride on a steam bath for two hours. On pouring into excess water a red solid was obtained. Crystallized twice from acetic acid, Mixture m.p. and once from nitrobenzene, the compound had the m.p. 293-294'. with a known specimen of the tetraacetyl derivative of the Bandrowski base 293-294'. 6. Condensation of 4-bromo-d ,b-dinitr0-4'-acetaminodiphenylamine with p-phenylenediamine.-Three-tenths of a gram of the acetyl derivative of the bromo-substituted dipbnylamine and 3 g. (excess) of p-phenylenediamine were dissolved in

SEPARATION OF DINITRO-1,4-DIBROMOBENZENES

553

50 mi. of alcohol, and refluxed for seven hours. Three-tenths of a gram of crude reaction product, a dark red crystalline substance, was obtained. This melts at 245-246", and no change in m.p. was obtained on crystallization from alcohol. The Beilstein test for halogen on this substance was positive. The filtrate from the original reaction mixture gave a negative test for halogen with silver nitrate and a positive test for nitrous acid with starch iodide paper. Anal. Calc'd for CloHlsBrN60a: C, 52.60;H, 3.95;N, 15.3. Found: C, 52.27; H, 4.47; N, 15.11. C . Reactions of 1 ,I-dibromo-%,6-dinitrobenzenewith p-phenyleaediamine. (a) 6-dinitro-4'-aminodiphenylamine.-One gram of 1 ,4Preparation of .&bromo-%, dibromo-2 ,6-dinitrobenzene1 0.60 g. (excess) of p-phenylenediamine and 0.3 g. of sodium acetate were added t o 40 ml. of alcohol. The solution turned dark-red immediately. After refluxing for fifteen minutes, water was added t o complete precipitation. A yield of 1.060 g. (98% of the theoretical) of a dark-green crystalline substance, m.p. 192-194", was obtained. Crystallized once from alcohol, m.p. 193-194". Anal. Calc'd for ClzHgBrN404: C, 40.79;H, 2.57;mol. wt., 353. Found: C, 40.70;H, 2.63;mol. wt. (Rast camphor method), 364. The acetyl derivative was prepared in the usual manner. Melting point of the crude material, a red crystalline substance, 270-271". Crystallized once from glacial acetic acid and once from nitrobenzene, m.p. 271-272". Anal. Calc'd for ClrH11BrN40s:C, 42.58;H, 2.78. Found: C, 42.56;H, 2.90. The acetyl derivative, when treated with p-phenylenediamine in alcohol solution, does not react. A mixture of 2,6-dinitro-4-bromo-4'-acetaminodiphenylamineand p-phenylenediamine in alcohol was refluxed for eight hours. On cooling, a quantitative yield of unchanged starting material was recovered. I n a second trial the reaction was attempted in the presence of potassium carbonate, potassium iodide, and copper bronze in alcohol as the solvent, but here also unchanged starting material was recovered. ( b ) Preparation of N , N'-bis-(%,6-dinitroJ-bromophenyl)-p-phenylenediamine.(1) From two moles of 1,4-dibromo-%,6-dinitrobenzene and one mole of p-phenylenediamine. -One gram of 1,4-dibromo-2, 6-dinitrobenzene1 0.150 g. of p-phenylenediamine and 1 g. of sodium acetate were placed in 40 ml. of alcohol. A dark mahogany color developed immediately. After refluxing for one hour, water was added to complete the precipitation of the dark-red substance. Eight-tenths of a gram of material m.p. 274-277" was obtained. After crystallization from glacial acetic acid, nitrobenzene, and again from glacial acetic acid, m.p. 276-277". There was no change in m.p. on further crystallizations. Anal. Calc'd for ClsHloBr2NBOs: C, 36.12;H, 1.69;Br, 26.73;mol. wt., 598. Found: C, 36.19;H, 1.75;Br, 26.70;mol. wt. (Rast camphor method), 621. (2) Preparation from /i-bromo-d,6-dinitro-4'-aminodiphenylamine and 1 ,4-dibromo2,8-dinitrobenzene.-A mixture of 0.2 g. of 4-bromo-2,6-dinitro-4'-aminodiphenylamine, 0.4 g. of 1,4-dibrom0-2,6-dinitrobenzeneand 0.2 g. of sodium acetate in 25 ml. of alcohol was refluxed for two hours giving 0.22 g. of material, m.p. 273-276". After one crystallization from glacial acetic acid, m.p. 276-277". Mixture m.p. with material from the previous preparation 276-277". Preparations Using 1-Chloro-4-Bromo-8,6-Dinitrobenzene A. Preparation of 4-bromo-%,6-dinitro-4'-amimdiphenylamine.--One gram of l-chloro-4-bromo-2,6-dinitrobenzene(prepared according t o the method of Joshi

554

C. J. SUNDE, G. JOHNSON AND C. F. KADE

and Saneg), 0.68 g. (excess) of p-phenylenediamine, and 0.5 g. of sodium acetate were refluxed in 30 ml. of alcohol for fifteen minutes. On cooling and addition of water, 1g. of a dark-green crystalline product, m.p. 192-194", was obtained. Crystallized once from alcohol m.p. 193-194'. Mixture m.p. with 4-bromo-2,6-dinitro4'-aminodiphenylamine, made from 1,4-dibromo-2,6-dinitrobenzene, 193-194'. Acetyl derivative, m.p. 271-272". Mixture m.p. with acetyl derivative of 4-bromo2,6-dinitro-4'-aminodiphenylamine, made from the dibromo compound, 271-272'. B . Preparation of N , N'-bis-(l,6-dinitro-~-bromophenyl)-p-phenylenediamine from the chloro compound.-(a) Two-tenths of a gram of the above 4-bromo-2,6-dinitro4'-aminodiphenylamine, 0.4 g. of l-chloro-4-bromo-2,6-dinitrobenzene,and 0.2 g. of sodium acetate in 25 ml. of alcohol were refluxed for two hours. On addition of water and cooling a quantitative yield of product was obtained. Crystallized once from glacial acetic acid, m.p. 276-277". Mixture m.p. with material made, starting with the dibromo compound, 276-277". (b) Five-tenths of a gram (0.00176 mole) of l-chloro-4-bromo-2,6-dinitrobensene, 0.095 g. (0.00088 mole) of p-phenylenediamine and 0.3 g. of sodium acetate in 25 ml. of alcohol were refluxed for forty-five minutes. On addition of water and cooling, 0.48 g. of product (91% of the theoretical), m.p. 268-271" was obtained. Crystallized from glacial acetic acid, nitrobenzene, and again from glacial acetic acid, m.p. No change in m.p. on further crystallizations. Mixture m.p. with mate276-277'. rial made from the dibromo compound, 276-277". SUMMARY

1. A simplified and improved method for the separation of the three isomeric &nitro-1 ,4dibromobenzenes, produced on nitrating pdibromobenzene, has been described. 2. The reactions of the dinitro-1 ,4-dibromobenzeneswith p-phenylenediamine have been studied.