US3927127A - Nitration process - Google Patents

Abstract

A process is disclosed for dinitrating 4-branched alkylchlorobenzenes predominantly in the 2- and 6-positions with a mixture of concentrated sulfuric and nitric acids as the nitrating agent. A subsequent step of amination yields 4-branched alkyl-2,6-dinitroanilines which are useful as herbicides and plant growth regulants.

Description

United States Patent Damiano 5] Dec. 16, 1975 NITRATION PROCESS 75 I to I h h D Primary ExaminerLeland A. Sebastian 1 nven r n Josep amlano Springfield Attorney, Agent, or Firm-Ernest G. Szoke; Michael E. Zall; Howard S. Katzoff [73] Assignee: Amchem Products, Inc., Ambler, Pa.

[22] Filed: Aug. 15, 1974 [21] Appl. No.: 497,802 [5 ABSTRACT q Applicauon Data A process is disclosed for dinitrating 4-branched alkyl- [63] Contmuation-m-part of Ser. No. 300,063, Oct. 24, fluorobenzenes predominantly i h 2- d 6- 1972 abandoned" positions with a mixture of concentrated sulfuric and nitric acids as the nitrating agent. A subsequent step }J-S.(il.2 260/646, 260/577 of aminafion yields 4 branched 2 [58] Flitid C07C 79/12 dinitroanilines which are useful as bi id d ie 0 are 260/646 plant growth regulanm [56] References Cited 10 Cl N D UNITED STATES PATENTS rawngs 3,077,502 2/1963 Leib 260/646 plant growth regulant mono-N-substituted-4-branched l alkyl-2,6-dinitroanilines, such as those described in US. Pat. Nos. 3,111,403; 3,257,190; 3,332,769 and 3,672,866, and more specifically the compound 4-tertbutyl-N-sec-butyl-2, 6-dinitroaniline.

The 4-branched alkyl-2,6 dinitroaniline compounds prepared by the method of this invention are represented by the formula:

wherein R is selected from the group consisting of branched chain hydrocarbons containing from 3 to 7 carbon atoms, such as iso-propyL' iso-, secand tertbutyl, iso-pentyl, etc.; and wherein R is selected from the group consisting of lower alkyl, cycle-lower alkyl,

chain other than straight chain. As used herein, with respect to R the term alkyl denotes both straight and branched chain hydrocarbons containing 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-amyl, sec-amyl, hexyl, etc.; alkyl groups of 3 to 60 carbon atoms are preferred, more preferable are the branched 3 and 4-carbon groups i-propyl, sec-butyl and t-butyl; the term cycloalkyl denotes monocyclic saturated hydrocarbons having 3 to 6 carbon atoms; such as cyclopropyl, cyclopentyl, cyclohexyl; the term cyclo-lower alkyl lower alkyl denotes groups such as cyclopropyl methyl, cyclo-hexylmethyl, etc, The term lower alkenyl denotes straight or branched chain hydrocarbons having 3 to 4 carbon atoms and at least one double bond such as allyl, 2- butenyl, 3-butenyl, pentyl, hexenyl and the like; the term lower alkynyl denotes straight or branched chain hydrocarbons having 3 to 4 carbon atoms and at least one triple bond such as propynyl, 2-butynyl, 3-butynyl, pentynyl and the like; the term lower-alkoxy-loweralkyl denotes a CH (CH ),,,O(CH group wherein m is 0 or 1 and n is an integer from 1 to 6, such as methoxymethyl, methoxyethyl, methoxypropyl, methoxyisopropyl, ethoxymethyl, ethoxyethyl, ethoxypropyl, ethoxyisopropyl, etc; the term di-lower-alkoxylower-alkyl denotes a (CH (CH ),,,O) C,,H group wherein m and n have the same meaning as above such as dimethoxymethyl, dimethoxyethyl, dimethoxypropyl, dimethoxyisopropyl, diethoxymethyl, diethoxyethyl, diethoxypropyl, diethoxyisopropyl, etc.

It is known to prepare, for example, the 4-tert-butyl 2,6 dinitroaniline compounds of this invention according to the following reaction sequence:

cyclo-lower alkyl lower alkyl, lower alkenyl, lower However, this method of preparing the 4-tert-butyl alkynyl, lower-alkoxy-loweralkyl and di-lower-alkoxylower-alkyl.

As used herein, the term branched chain hydrocarbon denotes any configuration of the hydrocarbon compounds suffers from two major drawbacks which prevent it from being an economically feasible method of producing the compounds. First, during the initial step of nitrating the para-t-butylphenol, the conditions of high acidity necessary to carry out this step produce a considerable loss of the tertiary butyl group from the paraor 4-position. Even carrying out this reaction at 7 reduced temperatures does not wholly overcomethe consequent loss of yield. Second, the step of converting the 4-tert-butyl-2,6-dinitrophenol to the corresponding chloro compound of Formula 111 requires the uneconomical use of a chlorinating agent such as thionyl chloride and a complexing agent such as dimethyl formamide.

The process of this invention thus provides an economical method of preparing 4-branched alkyl-2,6- dinitrochlorobenzenes, which are intermediates in the preparation of 4-branched alkyl-2,6-dinitroanilines. This process possesses distinct advantages over any other method known to the prior art for producing these compounds.

According to the process of this invention, a 4- branched alkyl-chlorobenzene is reacted with a mixture of concentrated nitric and sulfuric acids at elevated temperatures to yield 4-branched alkyl-2,6-dinitrochlorobenzene.

For example, 4-tert-butylchlorobenzene is reacted with a mixture of concentrated nitric acid and sulfuric acids at elevated temperatures to yield 4-tert-butyl 2,6 dinitro chlorobenzene:

Further, it is known that alkyl substituents on a benzene ring tend to orient further ring additions, either ortho or para, to the alkyl substituent. Thus, Boocock and Hickinbottom (Journal of the Chemical Society, pp. 2587-9, 1961) report that the nitration of 4-tertbutylchlorobenzene produced predominantly 4-chloro- Z-nitro-l-tert-butyl-benzene, i.e. mono-nitration ortho to the tert butyl group. Thus only a single nitro group was added in the ortho position to the tert-butyl group.

The method of this invention surprisingly produces dinitration in both meta positions to the branched alkyl group i.e. tert-butyl.

Still further, nitrating 4-chloroalkylbenzene is described by Nikolenko, etal. (Zhurnal Obshchei Khimii, Vol. 34, No. 12, pp. 4032-7, 1964). While a mixture of nitric and sulfuric acids is employed, the method produces only mono-nitration of the 4-butylchlorobenzene, and achieves only a 70-80% yield.

Still further, the text Methoden Der Organischen Chemie, Houben-Wehl, Vierte Auflage, Band X/ 1 Stickstoff Verbindungen 1, pp 553 to 581, in particular Table 39, describes the dinitration of a 4-branched alkyl-chlorobenzene i.e. 4-chloro-l [Z-methyl-butyl- (2)] benzene, with a large excess of fuming nitric acid (vis a vis concentrated sulfuric acid and concentrated nitric acid of this invention) to produce a compound HNO3/H2SO4 CH3 c CH3 CH3CCH3 CH3 H3 be specifically devised to meet the requirements of the compound being nitrated, and few generalizations regarding nitrating systems and the results of their use are, therefore, possible. For example, in the text, Nitration and Aromatic Reactivity by Hoggett, et a1. (Cambridge University Press 1971), the following isomer proportions for the mononitration of p-chloro-toluene were reported:

/ 58 i 42 1 Cl Thus the mono-nitration is about equally divided between the ortho position and the meta position, with respect to the alkyl substituent.

which has a nitro substituent in the ortho position and the meta position with respect to the chlorine substituent. It is well known in the art that the mere changing of acids used for nitrating will not change the orientation of substitution of the nitro substituents on the benzene ring. Yet by utilizing the acids (and reaction conditions) of the nitration method of this invention, an unexpected nitration of the two ortho positions (2,6 positions) with respect to the chlorine substituent is obtained in high yields.

Thus, the nitration process of this invention achieves surprising results in producing a 4-branched alkyl-2,6- dinitro chlorobenzene in a one step process and in accomplishing substitution of the nitro groups almost exclusively in the two ortho positions with respect to the chlorine substituent.

The results achieved by this nitration process are also surprising in that, contrary to what would be expected, the conditions of elevated temperature and high acidity prevailing during the nitration process do not cause loss of the tertiary butyl group from the 4-position of the 4-tert-butylchloro-benzene.

The method of this invention employs as a nitrating agent concentrated nitric acid together with concentrated sulfuric acid. The concentrated nitric acid should be greater than concentration by weight and preferably by weight. However, good results have been achieved using 80% concentrated nitric acid and red fuming nitric acid at a concentration of nearly The concentrated sulfuric acid is preferably' 98% concentration by weight with a specific gravity of 1.84, although fuming sulfuric acid may also be employed.

The use of the more concentrated nitric acid repreof these methods, it would be preferred to add the 4-tert-butylchlorobenzene slowly to the nitric acid, rather than reversing the sequence by adding the nitric acid to the starting material. It is considered that the sents a departure from the conventional use of 70% 5 latter sequence 'would produce a significant amount of nitric ac1d as a n1trat1ng agent. Moreover, the use of the the unwanted mononitro-4-tert-butylchlorobenzene. stronger n1tr1c acid is a significant departure in view of Since both of the concentrated acids employed in the the fact that, contrary to expectation and unlike nitramethod of this invention contain a certain amount of non of the corresponding t-butylphenol, the stronger water, the mixture of these acids used as the nitrating ac1d does not produce any significant loss of the teragent may be regarded as an aqueous solution. It is tlary butyl group from the 4-position. The materially preferred to use the mixture of the acids alone, without higher yield of the desired 2,6-dinitrot-butylchloroadditional solvents or media, and thus it may be seen benzene obtainable with 90% nitric acid, as compared that the nitration process of this invention, in its prewith 70% min C ac1d, employed under the same set of ferred form, takes place in an aqueous medium, essennltratmg conditlons, is shown in the following Table i. tially. However, it is possible to conduct the nitration process in an inert solvent medium. Useful solvents for TABLE I 1/ V-lt. chloro .1 Crude Crude benzene (Conc. HNO; H2504 T t Prod. Yield (moles) by Wt.) (moles) (moles) (C.) (hrs) (g) 7 (7d I Pure 2.6-D1n1tro- Mononitro- 2,6-Dinitrot-butylt-butylt-butyL chlorochlorochlorobenzene benzene Unbenzene knowns (71) (7:1 (7:1 7) M. P.

95 0 5 85 91-101 72 24 4 61 Gummy As the data contained in t u f u 7 he above Table llh'istrates th1s purpose include chlormated and unchlormated se 0 1e 0% nitric ac1d produces a substantlal proion of th al1phat1c hydrocarbons containing from 5 to 10 carbon P e mononltro t utylchlorobenzene, with a f d Conse uentu bl atoms, aromatic hydrocarbons, chloro orm an carq naccepta y ow y1eld of the d1n1troform.

Without intending that the scope of this invention be bontetrach-limde limited thereby it is theorized that the conce t t d The addition the 4 ten butylchlombenzene start Sulfu n ra 6 ing material to the mixture of nitric and sulfuric acids,

me am component of the nitrating agent em- 40 h bl k 10 ed in th th d f w en done on a laboratory scale, prefera y ta es P y e me o o t is invention reacts w1th the l nitric acid c v p ace, dropwlse, and w1th coolmg of the react1on m1xomponent to greatly increase the concenf tration of nitronium ions which are the immediate ture' These Rrecautlons are Simply a conseguenc? 0 ma t t the exotherm1c nature of the nitration react1on. Since c an s responsible for nltratlon. Nitric ac1d alone yields nitronium ions in accordance with the f ll there IS apparently no danger from potentially exploequation O Owmg sive reaction products, addition of the reactants may N03 H120 take place rapidly provided that steps are taken to However, th ddi i f ffi i t lf ic acid will assure cooling of the reaction mixture sufficient to yield the sa nitronium i concentration from only prevent degradation of the final product. However, as one-half of th i i l molar amount f nitric acid in the results obta ned wlth the procedure followed 1n accordance ith h f n i equation; Example 4 hereinafter indicate, where the temperature t! H2SOt 2 N0 1-1 0 +2Hso; of the reaction mixture is permitted to rise quickly, by It wlllbe observed that, as a consequence of the above means of the exotherm being generated, to the temperequatlon, 2 moles of nitrlc acid are required to dinitrate ature at which the reaction is to be conducted, a signifiaslngle mole of 4-tert-butylchlorobenzene. However, cant loss of yield appears to result. It is, therefore, in the method of this invention, it has been found necpreferred to maintain the reaction mixture at an interessary to employ about twice this stoichiometric mediate temperature in the range of 2040C. until amount. On the other hand, it has not been found necsuch time as the exotherm has subsided. The reaction essary to employ the concentrated sulfuric acid in a 2:1 mixture is then slowly brought to the higher temperamolar who to the nitric acid, as set out in the above ture at which the reaction is completed. equation. Rather, the hlghest observed yields resulted As exemplified hereinbelow, in order to prevent from usmg a m1xture of the two acids in approximately overheating of the reaction mixture, the reaction was a l.3:l to 15:1 range of molar ratios (sulfuric to niinitiated with chilled teactiants, and at below room temperature. While the exothermic reaction pro- Wh1le it is preferred to add the 4-tert-butylchloroceeded, cooling was effected sufficient to maintain the benzene to a m1xture of the nitric and sulfuric acids, it reaction mixture at a temperature of about 30C.

is also possible to dissolve the 4-tert-butylchlorobenzene starting material in the sulfuric acid and then proceed to add th1s mixture to the nitric acid. in either After the exotherm has substantially subsided (simply measured by a drop in temperature), the reaction is carried to completion by slowly elevating the tempera ture of the reaction mixture to 100C. or higher, and maintaining the reaction mixture at this temperature for a period of at least 1 hour, and preferably 2 hours. While temperatures in excess of 100C. for conducting the reaction should be approached with caution, the results as set out in Table IV hereinbelow, obtained with such temperatures, specifically llC., indicate that yields obtained with the higher temperatures will be approximately the same as those obtained using 100C.

When the reaction has been essentially completed, it has been found easiest to effect separation of the final product from the reaction mixture by utilizing phase separation, since the final product is solid at room temperature while the reaction remains liquid. This separation is thus simply accomplished by pouring the reaction mixture, after completion of the reaction, over cracked ice, and then proceeding to separate the solid final product from the reaction mixture by means of a Buchner funnel. Of course, it would also be possible to accomplish separation of the final product by means of solvent extraction. Suitable solvents are, for example, chlorinated and unchlorinated aliphatic hydrocarbons containing from 5 to carbon atoms, aromatic hydrocarbons, ethers, chloroform and carbontetrachloride. This method was employed in Example 1 hereinbelow because of the gummy nature of the final reaction product, which contained a substantial proportion of mononitro-4-tert-butylchlorobenzene.

The final reaction product, once recovered, is washed with water and a basic material, such as sodium bicarbonate, to remove any traces of acid which may have carried over with it during the recovering process.

The nitration process of this invention is preferably carried out at atmospheric pressure. although the process may be carried out at either elevated or reduced pressures as well.

As shown in Table IV hereinbelow, the crude yields obtained by the nitration process of this invention are very nearly quantitative. Gas chromatographic analysis of this crude product gives the percent of crude prod uct, which is 2,6-dinitro-4-tert-butylchlorobenzene.

The values under the column headed Pure Dinitro (percent) in Table IV, were derived by multiplication of the crude yield percentage and the percentage 2,6- dinitro calculated from gas chromatographic analysis. The percentage mononitro-4-tert-butylchlorobenzene and percentage unknowns were also calculated from gas chromatographic analysis.

Using 4-tert-buty1ch1orobenzene as the starting material, the nitration process of this invention will produce 4-tert-butyl-2,o-dinitrochlorobenzene in excellent yields. In order to prepare the herbicidally active and plant growth regulant compounds of Formula I, it is necessary to react the chlorobenzene intermediate with a primary amine. Such an amine is generally liquid and soluble in the organic solvents, such as toluene, xylene, alcohol, and the like, usually employed as the reaction medium. Where the amine is water soluble, there can be conveniently employed an aqueous medium, such as an alcohol-water solvent. The reaction is readily effected by adding a solution of the primary amine reactant, dropwise, to the chlorobenzene intermediate, both reactants being contained in the same solvent. The amine is ordinarily employed in an excess amount on a molar basis. Upon completion of the addition, the mixture is refluxed until the reaction is completed. The course of the reaction can be followed by the formation of the hydrochloride salt of the unreacted amine, which usually separates out as a solid precipitate. This precipitate is separated by filtering and the filtrate is evaporated to dryness. The solid residue obtained is recrystallized from an organic solvent, such as methanol, ethanol, or the like, to give a pure product.

The primary amine reactant is chosen on the basis of the mono-N-substituent which is desired in the resultant compound of Formula I. Thus, following the gen eral procedure as described hereinabove and as will be more specifically shown in the examples which follow, 4-tert-butyland 4-sec-butyl-2,6-dinitrochlorobenzene was reacted with inter alia the amines shown in Table II to give the corresponding compounds of Formula I as shown.

TABLE II Bu HR Melting No. Amino reactant Bu R Point. C.

1 Methylamine t-Butyl Methyl 129-130 2 Ethylumine Ethyl -73 3 i-Propylamine i-Propyl 71-73 4 n-Butylamine n-Butyl 63-65 5 sec-Butylamine s-Butyl 60-62 6 t-Butylamine t-Butyl 81-83 7 t-Pentylamine t-Pentyl 49-56 8 lsopentylamine i-pentyl 38-405 9 Allylamine Allyl 56-58 10 3-methoxy- Methoxy propyl 41-45 propylamine. 1 l 2,2-dimethoxy- B.,Bdimethoxyethyl l) ethylamine. 12 Cyclohexyl- Cyclohexyl 89-90 amine. 13 n-Hexylamine n-Hexyl Liquid l4 Cyclopropyl Cyclopropyl -1265 amine. 15 Cyclopropyl- Cyclopropylmethyl methylamine.

Melting N0. Amino reactant Bu R Point. C.

16 Methylamine sec-Butyl Methyl l l 17 Ethylamine Ethyl 44-45 18 Isop ropylamine i-Propyl Semisolid l9 sec-Butylamine s-Butyl l l 20 n-Butylamine n-Butyl Liquid 21 t Bu tylamine t- Butyl 3338 22 Cyclohexyl- Cyclohexyl 65-67 amine. 23 2,2-dimethoxy- Dimethoxyethyl Liquid ethylamine. 24 3-methoxy- S-methoxypropyl Liquid propylamine.

( 1) Dark organic liquid.

The invention will be more fully understood from the examples which follow, which examples are given by way of illustration and are not to be considered as limiting.

A. NITRATION Example 1 16.9 g. (0.10 mole) of 4-tert-butylchlorobenzene was added, dropwise, over a period of 10-15 minutes to a mixture of 18.5 ml. of 90% by weight nitric acid (sp.gr. 1.49) and concentrated sulfuric acid (sp. gr. 1.84), with stirring and with a temperature of 1520C. The reaction was slightly exothermic and after the addition was complete, the mixture was allowed to come to C. and was maintained at that temperature until the reaction was complete, cooling when necessary. When the liberation of heat from the reaction had ceased, the temperature was raised slowly to 6065C. and held at that level for 2 hours. The mixture was then cooled to room temperature and poured over cracked ice. The yellowish, semisolid reaction product was extracted with ether and this ether solution was then washed with portions of water, dilute sodium bicarbonate and again water. The ether solution was evaporated to dryness, leaving a residue of 18 g. of yellow, semisolid reaction product. The results of the nitration process just described are set out below in Table III.

reaction was allowed to raise the temperature to 30C. and completion of the reaction was noted by the subsequent drop in temperature. After the reaction was complete, the mixture was heated slowly to 7075C. and maintained at that level for 1 hour. The mixture was then cooled to room temperature and poured over cracked ice. The resultant reaction product was collected on a Buchner funnel and, after drying. gave 22 g. of a dark yellow, somewhat gummy, solid with a melting point of 8698C. Recrystallization from ethanol gave 20.5 g. of light yellow solid with a melting point of 1091l1C. The results are summarized in Table III hereinbelow.

Example 3 16.9 g. (0.10 mole) of 4-tert-butylchlorobenzene was added, dropwise, over a period of 10-15 minutes to a mixture of 28 ml. of 90% by weight nitric acid (sp.gr. 1.49) and 84 -g. of concentrated sulfuric acid (sp.gr. 1.84), with stirring and with the temperature at 15-20C. After complete addition, the temperature was allowed to come to 30C. where it was maintained until completion of the reaction. The mixture was then heated slowly to 95l00C. and maintained at this level for 45 minutes. The reaction mixture was next cooled to room temperature. poured over cracked ice and collected on a" Buchner funnel. The result was 23 g. of light yellow reaction product with a melting point of Example 2 9l-lOlC. The results are summarized in Table III 16.9 g. (0.10 mole) of 4-tert-butylchlorobenzene, herembelow TABLE 111 Yield 4-tert-Butyl- 90% lllvo, H250, Final Wt. Yield l u re Example Chlorobenzene (moles) (moles) TC Crude Crude Mono DI bn Dlnltro knowns l .10 mo]. .40 .50 -65 l8g 69.5% 86.5 13.5 60.0% 2 .10 mol. .60 .82 7045 22g 85.5% 5.6 90.6 3.7 77.0% 3 .10 mol. .60 .82 95-100 23g 89.0% 3.8 94.7 l.5 84.5%

Example 4 which is liquid at room temperature, was added, dropwise, over a l015 minute period to a mixture of 28 ml. of by weight nitric acid (sp.gr. 1.49) and 84 g. of concentrated sulfuric acid (sp.gr. 1.84.), with stirring and with the temperature at l520C. The exothermic 16.9 g. (0.10 mole) of 4-tert-butylchlorobenzene was added, dropwise, over a period of 10-15 minutes to a mixture of 28 ml. of 90% nitric acid (sp.gr. 1.49) and 84 g. of concentrated sulfuric acid (sp.gr. 1.84), with 11 stirring and with the temperature at l20C. The exotherm which occurred as a result of the addition was permitted to raise the temperature of the reaction mixture to about 100C. This required approximatly 5 12 solution of methylamine in 50 ml. of ethanol. The temperature was slowly increased as follows: C. for 1 hour, C. for 1 hour, C. for 1 hour, then 80C. for 5 hours. When the reaction was complete, about 100 minutes. The reaction mixture was maintained at this 5 ml. of water was added, which precipitated the reaction temperature by the addition of heat for another 1 hour product. This product was filtered, washed w1th porand 45 minutes. The reaction mixture was next cooled tions of water, and upon recrystallization from ethanol to room temperature, poured over cracked ice and yielded 2.5 g. of 4-tert-butyl-N-methyl-2,6-d1n1troan1- collected on a Buchner funnel. The result was 23.3 g. of line as orange needles melting at 129l 30C. light yellow reaction product. 10 By using a method similar to those described in the The reaction process, specifically described in the preceding examples, additional 4-tert-butyl-N-monoexamples above, was repeated with varying proportions substituted-2,6-dinitroanilines derivatives were preof nitric and sulfuric acids, different reaction times, and pared by reacting 4-tert-butyl-2.6-dinitrochlorobenunder different temperature conditions. The results are zene with the appropriate primary amine. These comsummarized in Table IV hereinbelow. 15 pounds, together with those mentioned in the preced- TABLE IV (7c) (7d t-Butyl- Dinitro Mononitro- 7!) chloro- HNO;X HNO, Wt. '71 t-Butylt-Butyl- (71) PUre benzene Con. H. -SOI T t Crude Crude chlorochloroun- Di. (moles) by wt.) (moles) (moles) (C.) (Hrsl Prod. Yield benzene* benzene** knowns nitro* M.P.

.10 90% .40 .56 -65 2 18 g. 87 13.5 60 .10 90% .60 .82 70-75 1 22 g. 86 91 9 78 86-98 .10 90% .60 .82 100 1 23 g. 89 95 5 91-101 .10 .60 8.2 100 1 251 g. 97 93 7 90 94-99 .10 90% .30 .50 100 1 22.2 g. 86 85 10 4.4 73 gummy .10 90% .40 .60 100 1 24.8 g. 96 90 0 10 87 85-100 .10 90% .50 .70 100 1 24.1 g. 93 94 0 6 87 88-98 .10 90% .60 .80 100 1 23.0 g. 89 95 0 5 85 91-101 .10 90% .30 .50 2 22.5 87 84 10 6 73 gummy .10 90% .40 .40 100 2 25.8 100 82 6.5 7 82 gummy .10 90% .40 .50 100 2 4.5 95 90 0 10 85 85-95 .10 90% .40 .60 100 2 24.8 96 94 0 4 90 85-95 .10 90% .50 .70 100 2 25.0 97 92 0 8 89 90-104 .10 90% .60 .80 100 2 25.4 98 92 0 8 90 80-95 .10 90% .40 .50 100 3 24.0 93 90 0 10 84 85-90 .10 90% .50 .50 100 3 22.9 89 83-92 .10 |00%*** .40 .60 100 2 25.5 99 88 2.3 9.7 87

semi- .10 100%*** .30 .50 100 2 23.9 92 63 29 7 58 SOlld .10 80% .40 .60 100 2 23.9 92 88 0 12 89 .10 90% .40 .60 2 24.2 94 90 0 10 85 .10 90% .40 .60 100 2 23.3 90 90 0 10 81 *lh-dinitru-t-hutylchlorohenzene *Z-nilro-t-butylchlorohenzenc *Red fuming sp.gr. 1.60 This run followed the procedure detailed in Example 4 The 4.tert'buty12*6'dmltrqchlqobenzene whlqh ls ing examples. are listed in Table II hereinabove. the react1on product of the n1trat1on process described I claim. m l q li l i g g 8?? f g 45 l. A process for preparing 4-R2,6-dinitrochlorobenf l .5 e er u y p S I u e zene compounds of the formula: d1n1troan1l1nes of Formula I. Th1s am1nat1on process 1s specifically described in the examples which follow: NO

2 B. AMINATION 50 Example 5 R Cl 1 g. of 4-tert-butyl-2,6-dinitrochlorobenzene was allowed to react with l g. of sec-butylamine by adding N02 the amine, dropwise. to a refluxing mixture of 50 ml. dry toluene and the 4-tert-butyl-2,6-dinitrochloroben- 55 zene. After complete addition, the refluxing was conwherein R is selected from the group consisting of tinued for 8 hours. The mixture was then cooled to branched chain hydrocarbons containing from 3 to 7 room temperature, the hydrochloride salt of the amine carbon atoms, comprising the step of treating a comfiltered off, and the toluene and unreacted amine repound of the formula: moved under reduced pressure. The thick material that 60 resulted was dissolved in hot ethanol. The reaction product. which was then crystallized by cooling, was R c1 4-tert-butyl-N-sec-butyl-Z,6-dinitroaniline with a melting point of 6072C.

Example 6 2.6 g. (0.10 mole) of 4-tert-butyl-2,6-dinitrochlorobenzene was reacted with 3.1 g. of a 40% aqueous with a mixture of concentrated sulfuric acid of at least 98% concentration by weight. and concentrated nitric acid of greater than 70 percent concentration by 13 weight at a temperature of from about 15C to about 1 15C for at least 1 hour, whereby the reaction is carried to substantial completion.

2. The process of claim 1, wherein the temperature is maintained at about C to about 40C until an exotherm, which is produced by the reaction, has substantially subsided; then slowly raising the temperature to about 60C to about 1 15C, and maintaining the temperature for a sufficient period of time to allow the reaction to be carried to substantial completion.

3. The process of claim 1, wherein the concentration of the nitric acid is at least 90 percent by weight.

4. The process of claim 1, wherein the step of treating in a mixture of concentrated sulfuric and nitric acids is conducted at a temperature of about l0OC. for a period of about 2 hours.

5. The process of claim 1, wherein the concentrated sulfuric acid is fuming sulfuric acid.

6. The process of claim 1, wherein R is tert-butyl.

7. The process of claim 2, wherein the concentrated sulfuric acid is fuming sulfuric acid.

8. The process of claim 2, wherein the concentrated nitric acid is at least 90 percent concentration.

9. The process of claim 8, wherein the concentrated nitric acid is about 98 percent concentration.

10. The process of claim 2, in the step of slowly raising the temperature, the temperature is raised to about to C.

Claims (10)

1. A PROCESS FOR PREPARING 4-R-2,6-DINITROCHLOROBENZENE COMPOUND OF THE FORMULA:

2. The process of claim 1, wherein the temperature is maintained at about 20*C to about 40*C until an exotherm, which is produced by the reaction, has substantially subsided; then slowly raising the temperature to about 60*C to about 115*C, and maintaining the temperature for a sufficient period of time to allow the reaction to be carried to substantial completion.

3. The process of claim 1, wherein the concentration of the nitric acid is at least 90 percent by weight.

4. The process of claim 1, wherein the step of treating in a mixture of concentrated sulfuric and nitric acids is conducted at a temperature of about 100* C. for a period of about 2 hours.

5. The process of claim 1, wherein the concentrated sulfuric acid is fuming sulfuric acid.

6. The process of claim 1, wherein R is tert-butyl.

7. The process of claim 2, wherein the concentrated sulfuric acid is fuming sulfuric acid.

8. The process of claim 2, wherein the concentrated nitric acid is at least 90 percent concentration.

9. The process of claim 8, wherein the concentrated nitric acid is about 98 percent concentration.

10. The process of claim 2, in the step of slowly raising the temperature, the temperature is raised to about 60* to 65*C.