THE JOURNAL of INDUSTRIAL the Residual Oil Distilled at Zoo

4.58 THE JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY Vol. 11, No. 5 the residual oil distilled at zoo mm. pressure. Un- We therefore undertook a systematic study of the changed aniline remaining in the distillate is removed synthesis of the quaternary iodides with a view to by diazotizing' in hydrochloric acid and heating establishing the simplest conditions which would the solution. The acid solution is then rendered give satisfactory yields of the pure compounds. Our alkaline, the supernatant quinoline extracted with many experiments need not be described in detail. ether, the ether solution dried, the ether removed, After carrying out the addition reaction under varying and the residual oil distilled at atmospheric pressure. conditions-in pressure flasks, in flasks under reflux Quinoline thus obtained boils at 238' (uncorrected). condensers, with and without the use of various The yield is 65 per cent of the calculated amount, solvents, and with varying amounts of the components based upon the weight of aniline taken. -we find that it is best to use equimolecular amounts Calculated for COHIN:N = 10.86 per cent Found: N = 10.73 of the alkyl iodide and the base and to carry out per cent, 10.69 per cent the reaction in a round bottom flask surmounted by a worm condenser. The flask should never be filled 0CT33 beyond one-third1 of its capacity. 2,4-DIMETHYLQUINOLINE, 1 - A mix- Depending on the nature of the base used, the re- O-C& v action may proceed spontaneously and violently N (as in the case of quinoline methiodide) or it may ture of 120 g. of paraldehyde and 200 g. of acetone require external heating (as in the case of quinaldine is saturated with dry hydrochloric acid and allowed ethiodide). The presence of an a-methyl group in to stand for 24 hrs., care being taken to exclude moisture. the molecule appears to decrease the rate of reaction. The mixture is then slowly added to 200 g. of aniline The product is usually obtained in the form of a dissolved in 400 g. of hydrochloric acid, and the syrup solid cake, which may be gradually dissolved by treat- finally heated during I hr. (in a water bath) under a ment with hot alcohol. The iodide crystallizes from return condenser. On rendering alkaline, a yellow the alcoholic solution on cooling. In general, the separates from the solution. The oil is extracted oil yields of the quaternary halide are satisfactory, with ether, and the ether evaporated. The residue, varying from 60 to 80 per cent of the theoretical. without further purification, is dissolved in an equal We have found, however, that small amounts of im- weight of hydrochloric acid and diazotized. Here purities in the reagents may decrease these yields very again precautions are taken to remove nitroso com- materially. pounds by extraction of the cold acid solution with All the quaternary halides are crystalline compounds ether. The aqueous solution is rendered alkaline of a more or less pronounced yellow color. Many and the yellow oil extracted with ether. The usual of them melt with decomposition. All of them are procedure is followed in the final purification of the water-soluble and ionize in solution. The iodine 2,4-dimethylquinoline. The compound, which is ob- content of any quaternary base may be rapidly and tained in 25 to 30 per cent yield, based upon the weight accurately determined by a slight modification of of aniline taken, boils at 260-264 (uncorrected) the Volhard method. This method served a useful under ordinary pressure. purpose in permitting us to judge the purity of our Calculated for CiiHnN: N = 8.92 per cent. Found. N 8.78 per cent, 8.73 per cent.2 products. The above procedure is very much simpler and far From the standpoint of the producer of photo- more rapid than that outlined by v. Be~er.~ sensitizing dyes the following quaternary halides are perhaps the most important : quinoline methiodide COLORLABORATORY BUREAUOB CHEMISTRY and ethiodide, quinaldine ethiodide, toluquinaldine WASHINOTON,D. C. methiodide, and ~,4-dimethylquinolineethiodide. We have prepared relatively large amounts of these com- INTERMEDIATES USED IN THE PFtEPARATION OF pounds and small amounts of a few other analogous PHOTOSENSITIZING DYES. 11-QUATERNARY iodides, all of which are described in the experimental HALIDES part. By CARL H. LVNDAND LOUISE. WISE EXPERIMENTAL Received February 24, 1919 The second step in the synthesis of photosensitizing QUINOLINE METHIODIDE--.When small amounts of dyes is the formation of quaternary iodides from the this product-less than IOO g.-are required, the follow- bases described in the preceding paper. These com- ing procedure is convenient: Equimolecular amounts pounds result from the direct addition of methyl, of methyl iodide and quinoline are mixed in a round ethyl or other alkyl iodide to the quinoline base. bottom flask, and allowed to stand at room temperature Many of these addition products have been described under a reflux condenser. The mixture gradually in the literature, but there is too little available in- becomes warm and crystals begin to appear in the formation on the best conditions for the preparation flask. Since the reaction is exothermic, the mixture of these compounds. finally reaches a temperature at which the methyl- iodide boils vigorously. When this point is reached 1 No special precautions are necessary. Tetrahydroquinoline is not present. the flask must be cooled in an ice bath to keep the * Our thanks are due to Messrs. Jenkins and Ellis, of the Nitrogen reaction from proceeding too violently. After a Laboratory of the Bureau of Chemistry, for the analytical data given in this paper. 1 This simple precaution is necessary. Well-annealed flasks filled * Loc. cit. half full frequently cracked during the course of the reaction. May, 1919 THE JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY 459 yellow cake of the methiodide has formed, the flask from 95 per cent alcohol is obtained in the form of is immersed in a hot water bath and heated for several lemon-colored needles which melt at I 90 O (uncorrected). hours to insure a complete reaction. The solid cake Dbbner and Miller' give a melting point of 195'. in the flask is then covered with 95 per cent alcohol Calculated for CloHeN.CHs1. I = 44.53 per cent. Found: I = 4440 and the heating continued until the methiodide has per cent. dissolved, On cooling and stirring, a crop of small, QUINALDINE ETHIODIDE-EqUimOkCUlar amounts Of bright yellow crystals is obtained which are shown to quinaldine and ethyl iodide are mixed in a flask which be quinoline methiodide, monohydrate, CsH?.CHJ. is then connected with a reflux condenser. The H20. In the recrystallization of the crude methiodide mixture is heated on a steam bath for 18 to 20 hrs. it is necessary to use enough 95 per cent alcohol to The crude cake thus obtained is then heated under insure the presence of sufficient water to form this a reflux condenser with just enough 95 per cent alcohol monohydp-ate, otherwise a mixture of the monohy- to cause complete solution. (This requires about drate and anhydrous methiodide (melting 90' to 8 parts by weight of alcohol to I part of the crude I 20 ") is obtained and recrystallization is required. ethiodide.) On cooling, the alcoholic solution deposits The monohydrate melts at 70' to 71 ' (uncorrected). quinaldine ethiodide in the form of coarse, straw-colored The melting point recorded by Marckwald and Meyer' or brown needles, decomposing at 23 I O to 234' (uncor- is 72'. The yield varies from 70 to 80 per cent of rected). Miethe and Book2 who previously prepared the theoretical. this compound give the melting point as z34"-z35O. Calculated for CsH7.CHaI.HzO: I = 43.91 per cent. Found: Calculated for ClaHsN CZHII I = 42 44 per cent. Found: I = 42.30 I = 43 93 per cent. per cent, 42.20 per cent. By allowing the monohydrate to stand for several The yield of ethiodide was 70 to 80 per cent of the days over sulfuric acid in vacuo, complete dehydra- theoretical. When the alcoholic mother liquors from tion takes place. The melting point of the dehydrated the first crop of crystals are concentrated to one- tenth of their initial volume, a second crop of the ethio- compound is 131 ' to 133 O (uncorrected). Marckwald and Meyer2 give 133" as the melting point of the dide is obtained. This represents only about 5 per anhydrous compound. cent of the theoretical yield, and the crystals are so Calculated for CPHIN.CH~I:I = 46.82 per cent. Found: I = 46 66 impure that they require further purification. per cent. The procedure outlined above proved very satis- In the preparation of larger amounts of quinoline factory, and we found no difficulty in preparing several methiodide, it is expedient to modify the above method kilograms of the ethiodide by this method. since it, becomes almost impossible to control the re- Attempts to shorten the procedure met with little action by cooling with an ice bath (as described). success. When the initial time of heating on the The following modification is used: Methyl iodide steam bath was decreased to IO hrs., the reaction did is heated to boiling in a flask connected by means not go to completion, and yield of ethiodide was ma- of a two-hole stopper, with a reflux worm condenser terially decreased. Similarly no advantage was gained and with a dropping funnel. The source of heat by carrying out the reaction at a higher temperature is then removed and the quinoline added through (150"). In this case we also obtained a 70 to 80 per the dropping funnel at such a rate that moderate cent yield.

Load more