US2429493A - Process for the bromination of 2,6-nitro chlor toluene - Google Patents

Description

1947- F. SIEVENPIPER ETAL 3 PROCESS FOR THBBROMINATION 0F 2,6-NITRO CHL-OR TOLUENE 3 Sheets-:Sheet 2 Filed July 11, 1942 INVENTORS J/eI/en az aer Zan rence H F/eZZ I BY H C 5 ATTORNEY Hale/ 2 c Oct. 21, 1941 F. SIEVENPIPER ETAL.

PROCESS FOR THE BROMINATION 0F 2,6-NITRO CHLOR TOLUENE Filed July 11, 1942 3 Sheets-Sheet 3 Q ,INVENTORS Fnederzc J/el e 77 z 67' Zawrence 19 7 83 ATTORNEY pr d c .for instance, if it 2,6-;nitro.chior,benzylbromide-to the correspond- ;ing rbenzyl alcohol. Operation of this process on a commercial scale is also ineiiicient and unecc-nomica1 becauseoi the retarding efiect of the diluentuponthe rateof reaction which decreases Patented Oct. 21, 1947 UNITED STATES P PROCESS Frederic 'Sievenpiper, Alden, N. Y., assignors Flett, Hamburg FOR THE BROMINATIQN OF 2,5- NITRO CHLOE TOLUENE and Lawrence H. to Allied Application July 11, 1942, Serial No. 450,628

15 Claims. 1

invention relates to an improved process of brominating a nuclearly substituted toluene for the production of the corresponding substituted benzyl bromide.

More particularly, the invention relates to an mp vedpre ess f r q i at s 2,6-nitr hl toluene to produceZfi-nitro chlor benzyl bromide.

German Patent 197,5 01 to Janson discloses the preparation of 2,6-nitro chlor benzyl bromide by adding a quantity of bromine to somewhat less than an equimolecular amount of 2,6-nitro chlor toluene at temperatures between 160 and 180 C- I dup ic in h rmc s of t Patent a laboratory scale it was'found that the bromine.- tion is sometimes accompanied by a side reaction and a decomposition which are explosively violent. Such a side reaction is generally accompanied by excessive foamin a sharp rise in temperature; and substantially complete decomposition of the bromination charge. Such explosive reaction constitutes .a serious safety hazard which is complicated by the extremely lachrymatory characterof the bromination prod- .uct.

W en it was attempted to carry. out the aforesaid procedure on a larger scale ,in apparatus of technical size, in which the reactive materials .were more confined than in laboratory apparatus, the charge exploded violently.

Gindraux l llelvetica .Chimica Acta, 12, page 931) discloses bromination of 2,6-nitro chlor jtolueneby a method similar to that of the aforesaid German patent, but in the presence of an inert diluent, such as ortho-dichlor benzol. Althoughthe difiiculties of the Janson method are somewhat lessened by the presence of the diluent, this 1method involves-costly and time-consuming separation and recovery of the diluent, .for in stance by .vacuum distillation of the reaction Such separation was found necessary,

was desired to hydrolyze the with decreasingconcentration of 2,6-nitro chlor toluene, resulting-in excessively long time cycles. Moreover, recovery of the diluent is complicated -by' the safetyhazards resulting from the corrosive nature of the bromination products.

It is an object of this invention to provide a process for preparing 2,6-ni;tro chlor benzyl 'bromideyby directbrominaticn of 2,6-nitro chlor toluene, in which any desired quantity of the reagents may be safely employed.

It is also an object of the invention to provide a process of the aforesaid type, capable of continuous operation, characterized by economy, efficiency, and convenience, and resulting in high yields of the desired bromination product in terms of the reagents consumed.

' Another object of the invention is to provide a process for brominating 2,6-nitro chlor toluene yielding a substantially uncontaminated reaction product, suitable, without preliminary purification, for the production of 2,6-nitro chlor benzyl alcohol by hydrolysis.

Other objects will in part be obvious and will appear in part from the following description of the process of our invention.

We have found :that the reaction of 2,6-nitro ch-lcr toluene with bromine can be carried out in a smooth, easily controllable manner involving substantially no explosion hazards and resulting in the formation of -2,6-r1itro chlor benzyl bromide, substantially uncontaminated with tar or decomposition products, by causing a limited quantity of -2,6-nitro chlor'toluene in the liquid phase to react with bromine in the gaseous phase at temperatures within the range of from about to about 290 C. in a reaction zone promoting intimate contact between theliquid and gaseous phases of the reaction mixture, and by controlling the time during which the reactants are maintained in the reaction zone at the'aforesaid temperature so that the said time is within the rangeof from about 0.5 to about 30 minutes.

The bromination according to the invention may be advantageously carried out as a continuousprocessin which a stream of bromine which,

by interrupting the reaction between .the reactants thus separated. The apparatus employed preferably comprises, in the reaction zone,an extended surface over which the liquid phase of the reagents flows in a thin layer, i. so as to insure intimate contact with the gaseous phase. Since relatively small quantities of reagents are present in the reaction zone at any instant, the liquid phase being in the formof a thin layer, control of th'reactio'n temperature is greatly facilitated, while stimulationof side reactionsby overheating :is substantially prevented. Th re- Berl porcelain.

erated in the vaporizing tube, pass through a tube 35 into the column 20 a short distance above its base; Vapors issuing from the top of column 20' pass through a vapor exit tube 35 to a condenser 31, from which the condensate flows into the reservoir 31. A vent 38 between the condenser 31 and reservoir 3| is provided to remove uncondensed vapors and gaseous reaction products from the system and may be advantageously connected to a recovery apparatus, not shown.

The modified apparatus, illustrated diagrammatically in Fig. 3, is preferably constructed entirely of glass, except as hereinafter noted. It comprises a reaction column at, packed with saddles 4.1, and surrounded by a 42'. A delivery tube 43 from a reagent reservoir (not shown) is connected to the top of column 40 and serves to introduce a liquid reagent into the column. An inclined vaporizing tube M connected to the base of the column, slants downward therefrom to an elbow 45. From this elbow, a supply tube 46 extends upward and is connected to a second reagent reservoir (not shown). The vaporizing tube 44 is provided with a heating jacket i! extending for a portion of its length between elbow 45'and column 45!. The heat supplied from this jacket is adapted to vaporize a liquid reagent entering the vaporizing tube from supply tube 46. A chamber 48 about 2 feet long and 2 inches in diameter extends downward from the base of column 48; this chamber is packed with Berl porcelain saddles 49 and provided with a heating jacket 51!. At the lower end of the chamber- 48 a trap 51 serves as an eXitfor liquid reaction products descending through the column 40 and chamber 48; the issuing liquid flows into areoeiver 52. The upper end of column 45! is laterally connected by means of a tube 53 about 3 inchesin diameter to the upper end of a downwardly extending tubular condenser 54, which is about 2 /2 feet long and 2 inches in diameter, packed with Berl saddles 55, and surrounded by a cooling jacket 55. The lower or exit end heating jacket of condenser 54 is connected through a trap 51 with the supply tube 46. A vent 58 between this trap and the condenser provides an outlet for uncondensed vapors and gaseous reaction prodnets, and is preferably connected to a scrubbing apparatus (not shown).

it The hydrolyzing apparatus shown in Fig. 4 comprises a flask 66 equipped with an agitator El, a thermometer 62, and a vapor exit tube 63 having its upper end laterally connected to a reflux condenser 64. At the lower end of this condenser a stratifying vessel 65 is provided, having an outlet 66 at its base controlled by a stopcock. During distillation of a mixture of two immiscible liquids the condensate flows from the condenser into vessel 65 and separates into layers, the upper layer returning to flask 60 through tube 63; while the lower layer is removed through outlet 66,.

In order that the process of the invention may be more readily understood, the following examples, carried out in the apparatus shown in the accompanying drawings, are given as illustrations thereof. It will be understood, however, that the invention is not limited thereto since numerous variations will be readily apparent to those skilled in the art.

Example 1 Bromination of 2,6-nitro chlor toluene by concurrent passage of a stream of the reagents through a reaction zone may be carried out in the apparatus illustrated in Fig. 1. A quantity of o-dichlor benzol is boiled in the still I1 so that its vapors, rising through jacket 14, and the reflux returning through the jacket from the air condenser, heats the column IE to a temperature of about 180 C. A mixture of 300 grams of 2,6- nitro chlor toluene (1.75 mols) and 300 grams bromine (1.87 mols), to which about 1 gram of red phosphorus is added, is placed in the funnel i0 and allowed to flow into column 12, by suitable regulation of stop-cock II, at the rate of about to 116 grams per hour. The reactants are in the liquid phase in the funnel in; the bromine is vaporized upon entry into the reaction zon l2 and the bromine vapor and liquid 2,6-nitro chlor toluene introduced at the aforesaid rate remain within the reaction zone at a temperature of about 180 C. an average of about 3 minutes. The liquid reaction product is collected in the receiver 18, and hydrogen bromide and excess bromin are removed by applying gentle suction at the outlet Hi.

In order to prepare 2,6-nitro chlor benzyl alcohol, the liquid bromination product may be advantageously mixed with about ten times its weight of 10% aqueous soda ash solution and the resulting mixture boiled for about 12 hours. Unchanged 2,6-nitro chlor toluene distills 01T, while the 2,6-nitro chlor benzyl bromide is hydrolyzed to 2,6-nitro chlor benzyl alcohol, the latter remaining in the aqueous portion of the hydrolyzing mixture. Upon completion of the hydrolysis and removal of the 2,6-nitro chlor toluene, the aqueous residue is cooled to 15 to 20 C. 2,6 nitro chlor benzyl alcohol, Which separates as a solid, may be recovered from the mixture by filtration.

The crude 2,6-nitro chlor benzyl alcohol thus obtained may be converted to the corresponding aldehyde by oxidation with chromic acid as is well known in the art.

Example 2 Countercurrent bromination of 2,6-nitro chlor toluene may be advantageously carried out in the apparatus illustrated in Fig. 2. The column 20 is heated tov about 180 C. by boiling a quantity of ortho-dichlor benzene in the still 25, so as to maintain a steady reflux in jacket 21 and con denser Bil. 450 grams of molten 2,6-nitro chlor toluene, mixed with 5 cc. of phosphorus trichloride, are placed in reservoir 23 and a quantity of bromine (about 280 grams) is placed in reservoir 3|. By regulating stop-cock 24, the 2,6-nitro chlor toluene is allowed to flow into column 20, at the rate of about 10 grams per minute, and simultaneously, the bromine is allowed to flow at the rate of about 6.3 grams per minute into the vaporizing tube 33. The latter is maintained at about C. by heat supplied from the heating bath 34, and the bromine, which is entirely vaporized, enters column 20 through tube 35. At these rates, the molar ratio of 2,6-nitro chlor toluene to bromine introduced into the column 20 is about 3 to 2. The bromine vapor rises in the column 20 and is therein admixed with the descending molten 2,6-nitro chlor toluene, the liquid phase in the column being extended in a thin film over the surfaces of the column and its packing in intimate contact with the vapor phase. The liquid reaction product is continuously removed from the base of the column 20 through trap 22 and collected in a suitable receiver. Under the foregoing reaction conditions, not all of the rising bromine vapor reacts with the descending 2,6-nitro chlor toluene, so that a mixture of hydrogen bromide and unreacted bromine issues from the top of column 20, and passes into condenser 31. The excess bromine is mainly condensed therein, and returns as a liquid to the reservoir 3 1. Hydrogen bromide, issuing from the condenser through the vent 38, may be recovered in a suitable apparatus (not shown). Bromination of the aforesaid quantity of 2,6-nitro chlor toluene requires about 45 minutes; the average time required for the flow of each particle of 2,6- nitro chlor toluene through the reaction zone is about 3 minutes.

For production of 2,6-nitro chlor benzyl alcohol, the reaction product, recovered in the receiver, is boiled for about 12 hours with approximately 4 liters of an aqueous 10% solution of soda ash to hydrolyze the 2,6-nitro chlor benzyl bromide contained therein. The vapors which emanate from boiling of the aqueous mixture, consisting mainly of steam and unreacted 2,6- nitro chlor toluene, are condensed, and by separating the non-aqueous portion from the aqueous portion of the condensate, 294 grams of 2,6-nitro chlor toluene are recovered (i. e. about 65% of the amount originally employed). The aqueous hydrolysis mixture remaining in the still is cooled to about 15 C. to solidify the crude 2,6-nitro chlor benzyl alcohol contained therein, and the product is recovered b filtration. The resulting crude 2,6-nitro chlor benzyl alcohol, upon conversion to the corresponding aldehyde by a wellknown sodium dichromate oxidation procedure yields 86.5 grams of 2,6-nitro chlor benzaldehyde, corresponding to a yield of about 51% of that theoretically obtainable from the unrecovered 2,6-nitro chlor toluene (156 grams). By Way of comparison, similar preparation of 2,6-nitro chlor benzaldehyde from the bromination product obtained by the Janson process (German Patent 107,501) results in yields which rarely exceed 20 to 30% of theory.

Example 3 Countercurrent bromination of 2,6-nitro chlor toluene may be carried out alternatively in the apparatus of Fig. 3. For this purpose, column 40 and vaporizing tube 44 are maintained at a temperature of about 180 C. by passing vapors of ortho-dichlor benzene boiling at atmospheric pressure through the heating jackets 42 and 41. The chamber 58, connected to the base of the column is heated to about 170 C. by passing the ortho-dichlor benzene reflux condensate from heating jackets Q2 and 41 through jacket 50. The condenser at is cooled to about C. by passing cooling brine through jacket 55. Molten 2,6-nitro chlor toluene at 50 to 80 C. is introduced into the top of column 40 through inlet tube 43 at the rate of about 8.4 pounds per hour; the average time required for each particle of 2,6-nitro chlor toluene to flow through the reaction zone is about 3 minutes, Bromine is simultaneously fed as a liquid through supply tube 6 to vaporizer 44, is vaporized therein and enters the base of column 40 at the rate of about 3.1 pounds per hour. The liquid bromine at elbow ,5 forms a seal preventing reverse flow of the vapor. The rate of vaporization of the bromine in the vaporizing tube 44 and hence its rate of introduction into column 451, may be regulated during the procedure by adjusting the level of the liquid bromine in said vaporizing tube so that more or less of the surface surrounded by heating jacket '41 is in convaporizer through trap 57, supply tube 46, and.

elbow :5. Hydrogen bromide, issuing from column 60 through condenser 54, passes out through vent 58, and may be recovered by the scrubbing means, mentioned above, but not shown. The liquid reaction product, after reaching the lower end'" of column 40, passes downward through chamber 48, flowing out through trap 5|, and is collected in receiver 52. V

For the purpose of converting the crude bromination product to the corresponding benzyl alcohol, the apparatus illustrated diagrammatically in Fig. 4 may be used. 800 grams of the crude bromination product obtained according to the first part of this example are placed in flask 60 together with a solution of grams sodium carbonate in 1600 cc. water, and 160 cc. of a 10% aqueous solution of sodium bisulfite. The mixture is heated to reflux temperature and agitated for 16 hours. The vapor, composed mainly of 2,6-1itro chlor toluene and steam, is condensed in condenser 64 and the condensate collected and allowed to stratify in vessel 65. The lower nonaqueous layer, consisting of 2,6-nitro chlor toluene, is withdrawn through outlet 66 at suitable intervals while the upper aqueous layer is returned to the flask 60 through tube 63. 465 grams of 2,6-nitro chlor toluene are thus recovered. Assuming all of the unrecovered portion to be 2,6- nitro chlor benzyl bromide, this represents a recovery of about 57% of the 2,6-nitro chlor toluene originally employed, and indicates that approximately 33% of the toluene intermediate introduced into column 40 had reacted with the bromine. After cooling the aqueous reaction mixture in the flask to 15 to 20 C., the crude 2,6- nitro chlor benzyl alcohol, which solidifies, is separated by filtration. A yield of about 196 grams is thereby obtained, representing about 78% of theory based on the amount of 2,6-nitro chlor toluene consumed.

The conditions and details of the process illustrated in the foregoing examples may be varied within suitable limits and the invention is not limited to the particular type of apparatus de-' scribed above. Devices other than those described above can be used for feeding the reagents into the reaction zone, and for maintaining the desired temperature. The maintenance of a liquid reflux in the heat exchange means for the reaction zone is advantageous in that any local tendency toward an undue increasein temperature is effectively controlled through the absorption of the excess heat by revaporization of the refluxing liquid portion of the heating medium.

It has been found that the presence of heavy metal salts, for instance those of iron, lead, mercury, silver, etc., in the reaction zone catalyze decomposition reactions and aifect the yield of the desired product adversely. In view of the corrosive nature of the reagents, the apparatus is therefore constructed from, or lined with, mate rials which are not easily attacked by the corrosive constituents of the reaction mixture, such as for instance glass, tantalum, or unreactive precious metals.

The presence of traces of moisture appear to have a beneficial effect on the rate of bromination and accordingly the reagents used need not be anhydrous if the amount of moisture therein is insufficient to form a visibly separated phase. If desired, halogenation catalysts, such as phosphorus, phosphorus trichloride, etc., or oxidizing substances such as potassium permanganate, or ascaridol (1,4-peroxido-p-methene-2) in amounts up to about 1% by weight of the 2,6-nitro chlor toluene may be introduced into the reaction zone to increase the rate of bromination.

Since variations and modifications may be made within the scope of the present invention, the foregoing illustrations and descriptions are to be interpreted as illustrative and not in 9. limiting sense, 7

We claim:

1. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises intimately contacting 2,6-nitro chlor toluene with gaseous bromine within a reaction zone at a temperature within the limits of from about 150 C. to about 200 C. for a period of time within the range of from about 0.5 to about 30 minutes, shorter periods of time within the foregoing range being employed at higher reaction temperatures and longer periods within said range being employed at lower reaction temperatures, and separating the resulting liquid phase from the gaseous phase of the reaction mixture at the end of said period.

2. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises treating 2,6-nitro chlor toluene in a thin layer with gaseous bromine at a temperature within the limits of from about 150 C. to about 200 C. for a period ranging substantially from 0.5 to 30 minutes, shorter periods of time within the foregoing range being employed at higher reaction temperatures and longer periods within said range being employed at lower reaction temperatures, and separating the resulting liquid phase from the gaseous phase of the reaction mixture at the end of said period.

3. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitr chlor toluene, which comprises intimately contacting 2,6-nitro chlor toluene with gaseous bromine at a temperature within the limits 150 C. to 200 C. for a period ranging substantially from about 0.5 to about 30 minutes all within which not substantially more than 40% of said 2,6-nitro chlor toluene reacts with the bromine, shorter periods of time within the foregoing range being employed at higher reaction temperatures and longer periods within said range being employed at lower reaction temperatures, and separating the resulting liquid phase from the gaseous phase of the reaction mixture at the end of said period.

4. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises flowing a thin stream of 2,6-nitro chlor toluene in intimate contact with gaseous bromine through a reaction zone at a temperature within the limits of from about 150 C. to about 200 C. at a rate such that the average time during which each particle of said stream is maintained within said zone is within the range of from about 0.5 to about 30 minutes, shorter periods of time within the foregoing range being employed at higher reaction temperatures and longer periods within said range being employed at lower reaction temperatures, and separating the resulting liquid phase from the gaseous phase of the reaction mixture at the end of said period.

5. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises flowing a thin layer of liquid 2,6-nitro chlor toluene in intimate contact with gaseous bromine through a reaction zone maintained at a temperature within the limits C. to 200 C. and separating the resulting liquid phase of the reaction mixture from the gaseous phase thereof at the end of a period ranging substantially from 0.5 to 30 minutes, shorter periods within the latter range being employed at higher reaction temperatures, and longer periods within said range at lower reaction temperatures.

6. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises flowing a thin layer of liquid 2,6-nitro chlor toluene in intimate contact with gaseous bromine through a reaction zone maintained at a temperature within the limits to C. and separating the resulting liquid phase of the reaction mixture from the gaseous phase thereof at the end of a period ranging substantially from 2 to 5 minutes.

'7. A process comprising flowing a thin layer of liquid 2,6-nitro chlor toluene in intimate contact with gaseous bromine through a reaction zone maintained at a temperature within the limits 150 C. to 200 C. separating the resulting liquid phase of the reaction mixture from the gaseous phase thereof at the end of a period ranging substantially from 0.5 to 30 minutes and within which the major portion of said 2,6-nitro chlor toluene remains unreacted, shorter periods within the foregoing range being employed at higher reaction temperatures, and longer periods within said range at lower reaction temperatures, subjecting the separated liquid phase of the reaction mixture to a hydrolyzing treatment, simultaneously distilling off unreacted 2,6-nitro chlor toluene contained therein, and recycling said unreacted 2,6-nitro chlor toluene for further treatment with bromine in said process.

8. A process comprising flowing a thin layer of liquid 2,6-nitro chlor toluene in intimate contact with gaseous bromine through a reaction zone maintained at a temperature within the limits 165 C. to 180 0., separating the resulting liquid phase of the reaction mixture from the gaseous phase thereof at the end of a period ranging substantially from 2 to 5 minutes and within which not substantially more than 40% of the 2,6-nitro chlor toluene reacts with the bromine, boiling the separated liquid phase of the reaction mixture with an aqueous alkaline solution to hydrolyze the bromination products contained therein, simultaneously recovering unreacted 2,6-nitro chlor toluene from the vapors of the hydrolysis mixture, and recycling the recovered 2,6-nitro chlor toluene for further treatment with bromine in said process.

'9. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises progressively introducing, as reagents, bromine and 2,6-nitro chlor toluene, into a reaction zone maintained at a temperature within the limits of from about 150 C. to about 200 C., intimately contacting the gaseous phase of the reaction mixture with the liquid phase thereof in said zone, and progressively removing the liquid and gaseous reaction products separately from said zone, the proportions of said reagents, the extent of said zone, and the rate of said introduction and removal being such that each portion of said 2,6-nitro chlor toluene remains in said reaction zone for a limited period ranging substantially from 0.5 to 30 minutes, shorter periods within the latter range being employed at higher reaction temperatures, and longer periods Within said range at lower reaction temperatures.

10. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,5-nitro chlor toluene, which comprises progressively introducing, as reagents, bromine and 2,6-nitro chlor toluene, into a reaction zone maintained at a temperature Within the limits of from about 150 C. to about 200 C., intimately contacting the gaseous phase of the reaction mixture with the liquid phase thereof in said zone, and progressively removing the liquid and gaseous reaction products separately from said zone, the proportions of said reagents, the extent of said zone, and the rate of said introduction and removal being such that an excess of bromine remains in the exit gases, and each portion of the substituted toluene remains in said zone for a period ranging substantially from 2 to 5 minutes.

11. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises progressively introducing, as reagents, bromine and 2,6-nitro chlor toluene into a reaction zone heated to a temperature within the limits 150 C. to 200 C., intimately contacting the gaseous phase of the reaction mixture with the liquid phase thereof in said zone, and progressively removing the liquid and gaseous reaction products separately from said zone, the proportions of said reagents, the extent of said zone, and the rate of said introduction and removal being such that each portion of the 2,6-nitro chlor toluene remains in said zone for a period ranging substantially from 2 to 5 minutes, and that the major portion of said 2,6-nitro chlor toluene remains unreacted.

12. An improved process for the production or 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises progressively introducing, as reagents, bromine and 2,6-nitro chlor toluene into a reaction zone heated to a temperature Within the limits 150 C. to 200 C., intimately contacting the gaseous phase of the reaction mixture with the liquid phase thereof in said zone, and progressively removing the liquid and gaseous reaction products separately from said zone, the proportions of said reagents, the extent of said zone, and the rate of said introduction and removal being such that each portion of the 2,6-nitro chlor toluene remains in said zone for a period ranging substantially from 0.5 to 30 minutes, shorter periods within the latter range being employed at higher reaction temperatures, and longer periods within said range at lower reaction temperatures, and such that an excess of bromine remains in the exit gases, and that from about 20% to about 40% of the 2,6-nitro chlor toluene reacts with the bromine.

13. An improved process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises progressively introducing, as reagents, bromine and 2,6-nitro chlor toluene into a reaction zone heated to a 12 temperature within the limits 165 C. to 180 C., intimately contacting the gaseous phase of the reaction mixture with the liquid phase thereof in said zone, and progressively removing the liquid and gaseous reaction products separately from said zone, the proportions of said reagents, the extent of said zone and the rate of said introduction and removal being such that each portion of the 2,6nitro chlor toluene remains in said zone for a period ranging substantially from 2 to 5 minutes.

14. A continuous process for the production of 2,6nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which comprises continuously introducing, as reagents, bromine and 2,6-nitro chlor toluene into a reaction zone heated to a temperature within the limits to 200 C., intimately contacting the gaseous phase of the reaction mixture with the liquid phase thereof in said zone is maintained, and continuously removing the liquid and gaseous reaction products separately from said reaction zone, the proportions of said reagents, the extent of said zone, and the rate of said introduction and removal being such that eachportion of the 2,6-nitro chlor toluene remains in said zone for a period ranging substantially from 0.5 to 30 minutes, shorter periods within the latter range being employed at higher reaction temperatures, and longer periods within said range at lower reaction temperatures, and such that'the major portion of the 2,6-nitro chlor toluene remains unreacted.

15. A continuous process for the production of 2,6-nitro chlor benzyl bromide from 2,6-nitro chlor toluene, which consists in continuously introducing, as reagents, bromine and 2,6-nitro chlor toluene into a reaction zone heated to a temperature within the limits C. to 180 C., intimately contacting the gaseous phase of the reaction mixture with the liquid phase thereof in said zone is maintained, and continuously removing the liquid and gaseous reaction products separately from said zone, the proportions of said reagents, the extent of said zone, and the rate of said introduction and removal being such that an excess of bromine remains in the exit gases, that each portion of the 2,6-nitro chlor toluene remains in said zone for a period ranging substantially from 2 to 5 minutes, and that from about 20% to about 40% of the 2,6-nitro chlor toluene reacts with the bromine.

FREDERIC SIEVENPIPER.

LAWRENCE H. FLETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Trans), pp. 411.

Certificate of Correction Patent N 0. 2,429,493.

read and within; col 12, line 20, claim 14, and line 41, claim 15, strike out the words is maintain and that the said Letters Patent should be read 'th these corrections therein the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 27th day of January, A. D 1948.

THOMAS F. MURPHY,

Assistant G'ommz'ssioner of Patents Oct. 21, 1947. c TROTTER AMMUNITION MAGAZINE Filed Aug. 10, 1945 2 Sheets-Sheet 1 III INVENTOR TQOTTER JOHN ATTORNEYS-1 Certificate of Correction Patent No. 2,429,493. October 21, 1947,

FREDERIO SIEVENPIPER ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 8, line 58, for tempera? ture read temperatures; column 9, line 52, for all Within read and within; column 12, line 20, claim 14, and line 41, claim 15, strike out the words is maintained; andthat the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 27th day of January, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

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