,,boston ,,university ,,graduate ,,school ,,thesis ,,meta ,,toluene ,,sulphonic ,,acid and ,,related ,,compounds ,submitted by ,charles ,francis ,hitchcock ,allen 7,a4,b41 ,boston ,university1 #aiai7 ,in partial fulfilment of requirements for the degree of ,master of ,arts #aibj ,,table ,,of ,,contents4 ,,meta ,,toluene ,,sulphonic ,,acid and ,,related ,,compounds ,,theoretical ,,discussion ,,sulphonation ,,of ,,ortho ,,toluidine ,,sulphonation ,,of ,,para ,,toluidine ,,diazotization ,,of ,,ortho ,,toluidine ,,sulphonic ,,acid4 ,,physical ,,properties ,,of ,,the ,,diazo ,,compound ,,decomposition ,,of ,,the ,,diazo ,,compound ,a ,,study ,,of ,,the ,,solution ,,obtained ,,by ,,the ,,decomposition ,,of ,,the ,,diazo ,,compound ,,conclusion ,,bibliography ,,meta ,,toluene ,,sulphonic ,,acid and ,,related ,,compounds ,theoretically toluene should yield three isomeric mono sulphonic acids1 in which the entering sulphonic acid group occupies the positions ortho1 meta1 or para to the methyl group4 ,the action of sulphuric acid on toluene was first investigated by ,jaworsky1 7,ztschr4 ,chem4 #a1bgb71 who described one toluene sulphonic acid as the resulting compound4 ,in #ahfi ,engelhardt and ,latschinoff 7,ibid4 #fag71 heated toluene with sulphuric acid and made and studied the potassium salt of the resulting acid4 ,they obtained two forms1 and identified them by fusion with caustic potash which converted them into the ortho and para cresols1 showing that sulphonation had taken place in the positions ortho and para to the methyl group4 ,barth 7,ann4 chem4 7,liebig7 #aeb1ia71 working similarly but fusing under different conditions which also caused oxidation of the methyl group to a carboxyl group obtained para hydroxy benzoic acid and salicylic acid 7ortho hydroxy benzoic acid47 ,this also proved that the sulphonic acid group had entered in the ortho and para positions4 ,anna ,wolkow 7,ztschr4 ,chem 7#ahgj7 #cba71 confirmed this work but ascribed the meta position to the sulphonic acid that passed into salicylic acid4 ,she also made two acid chlorides and amides and recorded their melting points4 ,fittig and ,ramsay 7,ann4 chem4 7,liebig7 #afh1bdb7 studied this result of ,anna ,wolkow1 and to determine and settle the constitutions of the sulphonic acids1 carefully prepared and purified their sulphonic acids2 they proved definitely that no meta acid was formed1 and that the products were only the ortho and para toluene sulphonic acids4 ,hubner and ,post 7,ann4 chem4 7,liebig7 #afi1dg7 worked on pure para brom toluene1 and obtained two para brom toluene mono-sulphonic acids1 one of which they proved to be the ortho acid by removal of the bromine by metallic sodium1 and oxidation to salicylic acid4 ,by exclusion they decided that the other acid must be one containing the sulphonic acid group in meta position to the methyl group4 ,f4,c4,g4 ,mller 7same as ,hubner and ,post7 made the barium salt of ortho brom toluene sulphonic acid1 and then removed the bromine by treatment with sodium amalgam4 ,the excess of alkali was removed by sulphuric acid1 the sodium sulphate removed by evaporation and crystallization1 and the residue dried4 ,on treatment with phosphorus pentachloride an oily toluene sulphonchloride was obtained2 this was decomposed by heating with water1 the hydrochloric acid removed by repeated evaporations1 and the syrup thus obtained evaporated to a crystalline condition4 ,several salts were made and studied4 ,his amide melted at #ij-ia4 ,because this acid differed in properties from the two previously mentioned1 ,mller considered it to be the meta toluene sulphonic acid4 ,about this time ,f4 ,gervor 7,ann4 chem4 7,liebig7 #afi1chc71 made ortho diazo toluene sulphonic acid by subjecting ortho toluidine sulphonic acid to nitrous fumes4 ,this was decomposed with alcohol under pressure1 and a sodium salt of the acid obtained2 this was converted into the chloride and an amide which melted at #adh1 differing in this and other properties from the amides of the ortho and para toluene sulphonic acids previously known4 ,in #ahgd ,pechmann 7,ibid41 #agc1aie7 obtained a quantity of para toluidine meta sulphonic acid by heating para toluidine with sulphuric acid1 and crystallizing out the para toluidine ortho sulphonic acid and disulphonic acids1 leaving the meta acid in solution because of its greater solubility4 ,the diazo compound was made by treatment of the acid in alcoholic suspension with nitrous fumes1 and decomposed with alcohol under pressure4 ,various salts of the resulting sulphonic acid were made and studied1 also the chloride and amide which melted somewhere below #ajj4 ,in #ahge ,pagel 7,ann4 chem4 7,liebig7 #agf1big7 working on ortho toluidine sulphonic acid1 made a toluene sulphonic acid which resembled ,muller's4 ,his amide melted at #ajd4 ,in #ahgg ,beckurts 7,ber4d4che4 ,ges4 #aj1 #idc71 seeking for a good method of obtaining pure ortho toluene sulphonic acid1 heated toluene and sulphuric acid in the ordinary way1 and made the potassium salts of the resulting acids4 ,by treatment with phosphorus pentachloride he obtained the acid chlorides which he separated by cooling to -#ae1 and filtering off the solid para compound4 ,the remaining liquid was transformed into an amide and purified by fractional crystallization4 ,two compounds were obtained with sharp melting points of #aec and #ajd4 ,from this work he concluded that the sulphonation of toluene yielded all the three possible acids4 ,fahlberg 7,am4 ,chem4 ,j4 #a1 #agj71 doubted ,beckurts' statement1 because although his acid showed different properties he neglected to prove its constitution by converting it into the hydroxy benzoic acid4 ,he therefore repeated ,beckurts' work1 and identified the amide melting at #aed as coming from ortho toluene sulphonic acid1 by conversion into salicylic acid4 ,the other amide with a sharp1 constant melting point of #ajh was oxidized1 and the products separated and identified as para sulphamine benzoic acid1 anhydro ortho sulphamine benzoic acid1 and acid potassium ortho sulphobenzoate4 ,these were the products one would expect from an oxidation of a mixture of the ortho and para toluene sulphonamides4 ,further proof that his acid was a mixture was obtained by mixing amounts of pure ortho and para toluene sulphonic acids1 and by repeated crystallizations a form was obtained which melted at #ajh4 ,f4,h4,s4 ,muller 7,ber4 d4 chem4 ,ges4 #ac1 #acdh71 mentioned the formation of meta toluene sulphonic acid by the action of sulphurous acid upon the corresponding diazo compound1 but gave no details except the melting points of his amide1 anilide1 and toluide4 ,claesson and ,wallin in #ahgi 7,ibid4 p4 #ahdh71 claimed that they had obtained meta toluene sulphonic acid by the action of chlorsulphonic acid upon toluene4 ,they used very large quantities of materials4 ,they obtained three acids1 and identified them as the ortho and para1 and called the third the meta acid1 despite the fact that they had knowledge of ,fahlberg's work4 ,the next step was undertaken by ,r4 ,otto 7,ibid1 #ac1 #abib71 at the request of ,beckurts4 ,he examined some of the latter's supposed meta toluene sulphonamide1 and found it to be a mixture of the amides of the ortho and para acids4 ,nevile and ,winther 7,ibid4 #ac1 #aidj71 while investigating the formation of amino sulphonic acids1 obtained a toluene sulphonic acid by heating ortho diazo toluene sulphonic acid with alcohol under pressure1 and also by reducing brom toluene sulphonic acid with sodium amalgam4 ,it was converted into the chloride and amide1--the latter melting at #ajf4e-ajg4e4 ,in #ahhf1 ,valin 7,ibid4 #bieb71 convinced by the work of ,otto that ,fahlberg's views were correct1 and that he and ,klason had not obtained meta toluene sulphonic acid1 again attacked the problem2 an acid was made and salts described4 ,in #ahia1 ,metcalf 7,am4 ,che4 ,j4 #ae1cja7 7,dissertation1 #ahib71 proved that decomposition of para diazo toluene meta sulphonic acid with ethyl alcohol under pressure resulted in the formation of para ethoxy meta toluene sulphonic acid in far greater quantity4 ,consequently the toluene meta sulphonic acid could not have been obtained by either ,pechmann or ,valin4 ,griffin1 7,dissertation1 #ahie71 prepared what he thought was a solution of the meta toluene sulphonic acid from the amide1 and made and studied several salts as well as the anilide and toluide4 ,however he did not investigate his solution to find out what it contained1 but went ahead on the assumption that he had a solution of this acid4 ,it is on the basis of his lack of investigation that ,i am working4 ,the derivatives of para toluene sulphonic acid have been made and studied by ,newell1 7,dissertation1 #ahie71 and are being investigated further4 ,he prepared para tolyl phenyl sulphone by the ,friedal-,crafts reaction1 para phenyl sulphone benzoic acid by oxidation of the sulphone with chromic acid1 its salts1 chloride1 amide1 and anilide1 and para benzoyl diphenyl sulphone from the acid by the ,friedal-,crafts reaction1 and studied their reactions and properties4 ,the analogous derivatives of ortho toluene sulphonic acid were made and studied by ,canter1 7,dissertation1 #aijj74 ,he prepared ortho tolyl phenyl sulphone by the ,friedal-,crafts reaction1 ortho phenyl sulphone benzoic acid by oxidation of the sulphone by potassium permanganate1 its chloride1 amide1 and anilide1 and ortho benzoyl diphenyl sulphone from the acid by the ,friedal-,crafts reaction4 ,the analogous derivatives of the meta toluene sulphonic acid with one or two exceptions have not been made or studied1 nor has the acid itself been prepared in a form which could be recognized4 ,the following derivatives of meta toluene sulphonic acid have been made and studied2 the amide by ,mller1 ,pechmann1 ,pagel1 ,beckurts1 ,f4,h4,s4 ,muller1 ,nevile and ,winther1 ,chase ,palmer1 ,klason1 ,valin1 ,noyes and ,walker1 ,metcalf1 and ,griffin2 meta sulphamine benzoic acid by ,limpricht and ,uslar1 and ,griffin2 meta toluene sulphon anilide and toluide by ,muller and ,wiesinger1 7,ber4 d4 chem4 ,ges1 #ab1acdh71 and by ,griffin2 the latter also made and studied several metallic salts4 ,the literature on the ortho and para toluene sulphonic acids and their derivatives is voluminous1 and covers a great many derivatives which have been thoroughly studied and whose structure has been determined4 ,the literature on meta toluene sulphonic acid is very meagre1 comparatively1 and all that could be found is mentioned in this paper4 ,this would seem to indicate that investigators have avoided this series1 and apparently the reason is due to the difficulties encountered in isolating the free acid4 ,,theoretical ,,discussion ,the object of this paper is to prepare a solution of meta toluene sulphonic acid1 as probably obtained by ,griffin1 by the most promising of the investigated methods and to find an acceptable one for isolating the acid in the solid state4 ,after a solution is obtained similar to that found by ,griffin1 7loc4 cit471 the intention is to remove as much water as possible by distillation under diminished pressure and then to precipitate the acid by the method of ,kastle1 7,amer4 ,chem4 ,j41 ,vol4 #dd1 page #dhc71 namely saturate the remaining solution with gaseous hydrochloric acid4 ,it is hoped that in this way the solid acid may be obtained which can then be studied4 ,as has been proved by previous experimenters and discussed above1 no direct method of sulphonating toluene will give any of the meta sulphonic acid4 ,therefore to get a compound containing a methyl group with a sulphonic acid group in the position meta to it some compound with these already in that position and containing some other group which can be replaced by hydrogen might be used1 i4e4 a disubstituted toluene4 ,the two groups which can be readily replaced by hydrogen are the amino group and bromine1 the former by the diazo reaction and the latter by treatment with metallic sodium2 the easier of the two to prepare and replace is the amino group and this is the one made use of in this synthesis4 ,this replacement has been widely studied 7,amer4 ,chem4 ,j41 by ,palmer #h1 #bdc2 ,orndorff #i1 #chg2 ,graham #aa1 #cai2 ,dashiell #ae1 #abd2 ,metcalf #ae1 #cja2 ,parks #ae1 #cbj2 ,shober #ae1 #cgi2 ,beeson #af1 #bdd2 and ,dissertations by ,weida1 ,cameron1 and ,chamberlain1 all #ahid471 and the various conditions affecting it determined4 ,the foregoing investigators decomposed their diazo compounds with alcohols sometimes using certain substances to cause the alkoxy or hydrogen reactions to take place4 ,later investigators 7,buchka1 ,berichte #bc1 #afbh1 ,st4 ,von ,niemantowski1 ,ibid41 #cd1 #ccbe 7#aija71 ,ullman and ,bieleck1 ,ibid41 #cd1 #bagd1 and ,bigelow1 ,j4 ,amer4 ,chem4 ,soc41 ,vol4 #da1 #aeff71 have shown that this decomposition is greatly increased by the presence of copper powder4 ,as the first method has been more extensively studied it was adopted in this case4 ,the action of methyl1 ethyl1 and n-propyl alcohols on diazo compounds has been well studied by the above authors1 and it has been shown that the first two at ordinary pressures give the alkoxy reaction either in whole or in part2 n-propyl alcohol gives the hydrogen reaction only4 ,also the first two give the hydrogen reaction in the presence of zinc dust or sodium carbonate1 but in these cases form salts of the acid4 ,on account of its rarity n-propyl alcohol was not used1 but n-butyl alcohol which is available in large quantities and in a pure condition was employed4 ,recent advances in fermentation as applied to organic chemistry have made this substance easily obtainable as a byproduct in the production of acetone which was needed in large amounts during the late war4 ,its use was found to be successful2 it boils at #aag and so can be easily distilled off after decomposition has been effected without a great increase in temperature above the boiling point of water1 which increase ,griffin 7loc4 cit47 showed to cause carbonization4 ,for this reason i-amyl alcohol although available was not considered1--also higher alcohols because of this fact and because of their rarity4 ,of the four amino toluene sulphonic acids theoretically possible in which the sulphonic acid group is in the meta position in reference to the methyl group only two are commonly known1 ,no4 #a1 and ,no4 #b4 ,,ch#c ,,ch#c ,,ch#c ,,ch#c _/ _/ _/ _/ _/ _/ _/ _/ _/ ,,nh#b _/ _/ ,,nh#b _/ ,,hso#c _/ _/ ,,hso#c _/ ,,nh#b _/ ,,hso#c _/ _/ _/ _/ _/ _/ _/ _/ ,,nh#b ,methods of preparing ,no4 #a and ,no4 #b were found but without details1 so a method had to be worked out to obtain them easily and in good yield4 ,after a little experimenting ,no4 #a1 or ortho toluidine sulphonic acid was readily obtained in good yield and in a fairly pure condition4 ,no4 #b1 or para toluidine meta sulphonic acid was obtained in only a ten per cent yield and by means of a much more difficult method of procedure4 ,the preparation of this acid was undertaken first and consumed a long time2 ,griffin did his work starting with this acid and ,i hoped to get as far as he did earlier4 ,it was then available in the market as was the ortho toluidine sulphonic acid1 but now neither are available4 ,the methods employed by earlier investigators when they wished to isolate their diazo compounds was to suspend the substance to be diazotized in alcohol1 and then pass in nitrous fumes generated by dropping concentrated nitric acid onto arsenious oxide4 ,the diazo compound from ortho toluidine sulphonic acid is so nearly insoluble in water that it was found possible to diazotize it in water suspension1 and generate the nitrous fumes in the solution itself by adding a solution of sodium nitrite to the water suspension containing hydrochloric acid4 ,after a short time the diazo compound separates out and can be filtered off1 washed and dried4 ,it is a very stable substance as compared with other diazo compounds4 ,this method was worked out1 there being no mention of it in the literature4 ,,sulphonation ,,of ,,ortho ,,toluidine ,of the possible sulphonic acids of ortho toluidine the commercial product of former days was the one in which the sulphonic acid group was in the para position to the amino group1 and meta to the methyl group2 thus this acid could find use in preparing the toluene meta sulphonic acid if a method of replacing the amino group by hydrogen could be found4 ,this acid is not now on the market in ,america because of its limited use in dyestuffs4 ,it is mentioned in ,schultz and ,julius1 78,farbestoff ,tabellen01 #ahid ,edition1 ,trans4 by ,f4 ,c4 ,green71 ,cain1 78,the ,manufacture of ,intermediate ,products for ,dyes07 and ,nevile and ,winther1 7,ber4 d4 chem4 ,ges4 #ac1 #aidj471 which latter give a method of preparation which was used industrially1--the baking of ortho toluidine sulphate4 ,their description is rather indefinite but after a few preliminary trials a suitable method was found4 ,i will describe all the experiments attempted1 and include the one finally adopted4 ,the ortho toluidine used was 78,practical407 obtained from ,eastman ,kodak ,co4 ,experiment #a4 ,ortho toluidine was suspended in water and conc4 sulphuric acid added with vigorous stirring until all the amine had dissolved4 ,the solution was heated to boiling until the sulphate had dissolved1 and then cooled and the crystals thus obtained filtered off and dried4 ,this was then powdered and ground with some powdered oxalic acid4 ,these mixtures with and without oxalic acid were then baked until a sample was completely soluble in sodium hydroxide4 ,the mass had become a deep grayish purple4 ,it dissolved in water to give a deep red solution4 ,nothing satisfactory was obtained from any of these bakes1 the formation of a red dyestuff as mentioned by ,nevile and ,winther seeming to be formed in a great quantity and very easily4 ,hence this method was discarded4 ,experiment #b4 ,in this case an excess of sulphuric acid was used4 ,after the oxalic acid had all been decomposed or driven off the mass turned black and became very pitchy4 ,nothing could be done with it so it was thrown away4 ,experiment #c4 ,in this case an excess of ortho toluidine was used4 ,the red dyestuff was formed in great amount and very easily4 ,the temperature was kept below #aie to lose none of the toluidine which boiled at #aii4 ,experiment #d4 ,this method gave the best results and is the one employed in the preparation of all the material used in the thesis4 ,equal weights of ortho toluidine and sulphuric acid 7#ajj;gms4 of each were used2 #ajj;gms4 of ortho toluidine is #ajh;cc41 and #ajj;gms4 of sulphuric acid 7s4 g4 #a4hd7 are #ef;cc471 were mixed and baked at #aij-aie until a sample would dissolve in ten per cent sodium hydroxide solution to give a clear solution2 this took one and a half hours4 ,the mixture at first melts in the solution of the sulphate and sulphuric acid formed by the heat of combination2 as heating is continued it gradually becomes solid and finally very hard2 it has become gray in color4 ,when it is perfectly dry a test is made to see if it dissolves in sodium hydroxide giving a clear solution4 ,if so1 sulphonation is complete4 ,by using an oven with a glass door the reaction mixture can be watched and the completion of the baking observed4 ,however the test for complete solubility should always be made4 ,the addition of powdered oxalic acid to the reaction mixture did not seem to be of advantage1 because no visible reaction commenced until this had been driven off or decomposed4 ,it is usually added in producing sulphonic acids by baking the sulphates of the amines to increase the porosity of the mass and thus facilitate removal of the product4 ,however here the only effect seemed to be to retard the reaction1 as the product was the sane hard grayish mass as without the acid1 and it was just as difficult to dig it out4 ,it took an hour longer to complete the reaction with the addition of the oxalic acid4 ,the best results were obtained when the temperature of the oven was kept at #aic1 although five degrees variation did not appreciably affect the product4 ,a lower temperature gives little or no action1 while a higher one drives off the ortho toluidine and also seems to favor the formation of the red dyestuff4 ,as stated above1 complete sulphonation is shown by the solubility of the acid in ten per cent sodium hydroxide solution4 ,if any unchanged amine is present as sulphate the solution will become milky due to liberation of the insoluble amine4 ,on boiling a solution of the acid a slight hydrolysis takes place so that the smell of ortho toluidine is present1 yet the solution is always perfectly clear4 ,the product or 8bake0 appears as a hard grayish mass1 slightly porous4 ,it is dug out1 pulverized1 boiled up in a large evaporating dish1 containing water and a little 7#aj;cc47 hydrochloric acid1 with animal charcoal and filtered4 ,the solution should be almost colorless4 ,the effect of the slight amount of hydrochloric acid was accidental2 the first solutions were always a deep red color due to some of the red dyestuff seeming to be present1 and the longer the solution was boiled the redder it got4 ,a little acid seems to prevent this entirely4 ,the solution is evaporated on a water bath until a scum has formed on the surface when it is allowed to cool and crystallize4 ,it crystallizes in small almost white needles1 which appear to fill the entire liquid2 this is deceptive as on filtering the bulk is considerably reduced4 ,they fall to a powder when they are dry4 ,if they are colored red or pink they are washed while still on the filter with water2 alcohol does not remove this color4 ,the acid as formed has no melting point1 but chars and decomposes on heating4 ,a sample was tested for nitrogen and sulphur with very good positive results4 ,on fusion with caustic soda and acidification of the product a positive reaction was obtained on the addition of bromine water as is customary with phenols4 ,it was identified as identical with the acid of ,nevile and ,winther 7loc4 cit47 by conversion thru the diazo compound into dinitro ortho cresol1 melting at #he4h as described under the description of the diazo compound4 ,,sulphonation ,,of ,,para ,,toluidine ,metcalf1 7loc4 cit471 gives a method for the preparation of the sulphonic acids of para toluidine1 and states that both the possible acids are formed1 with the meta position 7referred to the methyl group7 in good yield4 ,schultz and ,julius1 78,farbestoff ,tabellen01 #ahid ,edition1 ,trans1 by ,f4 ,c4 ,green71 and ,nevile and ,winther1 7loc4 cit471 say that the sulphonation of para toluidine gives a mixture of the sulphonic acids1 with the ortho 7referred to the methyl group7 sulphonic acid in a much greater yield4 ,as the sulphonation of para nitro toluene gives 7,dissertation1 ,r4 ,s4 ,norris1 ,,bpl4 #eigf4aji7 a ninety-five per cent yield of the ortho sulphonic acid1 it would seem as though the amino compound should give a large yield of the acid 7sulphonic acid group ortho to the methyl group17 and such was found to be the case4 ,i followed ,metcalf's directions as follows3 in an apparatus fitted with an automatic stirrer and a thermometer ,i placed #bjj grams 7#aaj;cc47 of twenty per cent fuming sulphuric acid4 ,i then slowly added with rapid stirring #ajj;grams of powdered para toluidine which was obtained from the ,newport ,chemical ,works4 ,the addition took thirteen minutes4 ,the initial temperature of the solution was #ah;,c4 ,the maximum was obtained when about half the toluidine had been added and was #adh;,c4 ,the final temperature was #acj;,c4 ,after addition was complete ,i stirred for five minutes1 and then slowly heated the mixture to #ahj;,c4 and kept it there for an hour4 ,sulphonation was then complete4 ,i then poured it into an equal volume of cold water 7#bbj;cc47 in an evaporating dish and allowed it to stand over night4 ,the next day the dish seemed filled with grayish crystals2 these were filtered off4 ,the solution was allowed to stand for four weeks with no results4 7,metcalf says that the disulphonic acid separated in three weeks from his solution47 ,i dissolved the crude acid obtained as above in ten liters of water 7,metcalf's directions7 and precipitated the excess of sulphuric acid with barium hydroxide1 and then filtered the solution4 ,it was a clear brownish color4 ,i then evaporated to #ajj;cc4 ,a smell of para toluidine was always present in the vapor indicating a probable hydrolysis of the acid4 7,nevile and ,winther 7loc4 cit47 say that this sulphonic acid can be hydrolyzed by heating with water71 ,a test after sulphonation and before evaporation showed a sample to be completely soluble in water1 and no cloudiness was produced when a sample was dissolved in sodium hydroxide1 as is the case if a solution of para toluidine sulphate is dissolved in the same reagent4 ,when the volume had reached #ajj;cc4 a light brown crust had formed on top of the liquid and on cooling and filtering two products were obtained2 a light brown powdery substance in larger amount 7#dg4e grams471 and a small amount of hard square brown crystals4 ,on evaporating the filtrate nearly to dryness more material separated which did not look like either of the above substances2 it weighed twenty grams4 ,this has not been investigated as yet4 ,as the brownish powdery substance was mixed with the flat crystals produced above1 a method had to be found to separate them and purify each4 ,i screened them as much as possible with good results4 ,i removed the last of the fine powder by dissolving it off with hot water4 ,metcalf said that they could be separated by their difference in specific gravity in fifty per cent alcohol but this method was unsuccessful4 ,i boiled up the aqueous solution of the powdery substance with animal charcoal1 filtered and evaporated to crystallization4 ,square1 flat1 white crystals were obtained identical in all but color with those mentioned above4 ,they are soluble with difficulty in cold water1 readily in hot1 and insoluble in alcohol4 ,in these properties and in appearance they compare to the ortho sulphonic acid of para toluidine as made and described by ,parks1 7,dissertation1 #ahib74 ,metcalf and ,nevile and ,winther say that the meta sulphonic acid of para toluidine forms needles1 but ,i obtained nothing that could in any way be called needles4 ,this sulphonic acid had no melting point1 but charred and decomposed4 ,a test for elements showed nitrogen and sulphur to be present4 ,the aqueous solution had a strong acid reaction to litmus4 ,in order to see if this might be the desired acid ,i tried to prepare an acid chloride with phosphorus pentachloride in the usual way1 and then intended to convert it into the amide and get a melting point for identification4 ,i used equal weights of the acid and phosphorus pentachloride4 ,i ground them together at ordinary temperature in a mortar3 no result4 ,i heated it on a water bath3 no result4 ,i heated it on a gauze over a flame3 no result except decomposition and carbonization4 ,however ,i poured water into the mixture and decomposed the excess of phosphorus pentachloride1 and filtered4 ,a gummy brownish mass remained which was insoluble in all reagents tried1 7methyl and ethyl alcohol1 benzine1 petroleum ether1 7#dj-fj71 water1 carbon tetrachloride1 dilute hydrochloric acid1 acetone1 and acetic acid47 ,ethyl ether extracted a very small amount1 just enough to color it yellow1 and leave a yellow color on porcelain on evaporation1 but not enough to make a study of the properties4 ,on shaking up with concentrated ammonia the mass became very finely divided1 but no solution appeared to take place2 on filtering and evaporating to dryness there was no residue4 ,the material mentioned above as being the final product from the sulphonation of para toluidine1 obtained in a yield of twenty grams or ten per cent yield and then uninvestigated1 has since been identified as the acid ,i was looking for1 or para toluidine meta sulphonic acid4 ,a small amount was cooled and diazotized in the usual manner2 the diazo compound seemed to be insoluble in the amount of water used1 for a white crystalline needle-like precipitate appeared4 ,this was decomposed by boiling with dilute nitric acid 7,nevile and ,winther1 loc4 cit471 and on cooling small tufts of yellow needles separated4 ,these were filtered off and dried1 then recrystallized from alcohol4 ,the best portions of these were then recrystallized from ether and the melting point determined4 ,they melted at #gi4e-gi4h 7uncorr474 ,nevile and ,winther gave #gi-hj1 showing that they did not purify their compound4 ,the product is dinitro para cresol1 or #c-nitro1 #d-;hydroxy1 #e-nitro toluene4 ,,diazotization ,,of ,,ortho ,,toluidine ,,sulphonic ,,acid4 ,nevile and ,winther 7loc4 cit471 stated that they obtained a diazo compound from their ortho toluidine sulphonic acid and described a few properties1 but gave no details of manipulation1 so ,i made several trials to determine the best acceptable method4 ,experiment #a4 ,i suspended some ortho toluidine sulphonic acid in denatured alcohol1 and passed in a rapid current of nitrous fumes1 generated by dropping concentrated nitric acid into a saturated solution of sodium nitrite1 for fifteen minutes4 ,the suspension became slightly warm1 and rather pasty at the end4 ,i allowed it to stand a half hour1 and at the end of that time it had become very thick and pasty4 ,i then filtered it off by suction1 washed with ether1 and dried4 ,experiment #b4 ,the procedure used was the same as above using ethyl alcohol in place of denatured alcohol1 but for some reason no diazotization appeared to take place4 ,the acid was filtered off and used again4 ,experiment #c4 ,a saturated water solution of the acid was made by boiling some of it up with water1 cooling and filtering4 ,no precipitate appeared on passing in nitrous fumes4 ,experiment #d4 ,some of the acid was dissolved in sodium carbonate solution1 sodium nitrite solution added1 and after cooling1 concentrated hydrochloric acid added drop by drop4 ,nitrous fumes were given off1 but no precipitate appeared4 ,experiment #e4 ,this seems to be the best method and the one employed hereafter in the preparation of all the material subsequently used4 ,the solid ortho toluidine sulphonic acid is suspended in concentrated hydrochloric acid and vigorously stirred4 ,the solution becomes warm and the crystals change in appearance1 probably due to the formation of the hydrochloride4 ,the mass is then cooled to #e1 and sodium nitrite solution added slowly with stirring4 ,immediate reaction takes place1 and the mass becomes very pasty as in the first experiment4 ,after obtaining a reaction with starch iodide paper the mixture was allowed to stand a half hour1 then filtered by suction1 washed with ether and dried4 ,in appearance it was identical with the diazo compound obtained in experiment #a1 and can be kept in the same way4 ,that it was a diazo compound was shown as follows3 ,it was spotted on a piece of filter paper with an alkaline solution of ,h acid--a red coloration indicates the formation of a red azo dyestuff4 ,some of the diazo compound was boiled with dilute nitric acid as described by ,nevile and ,winther1 and a yellowish precipitate of needles obtained1 which on recrystallization from denatured alcohol gave light yellow needles of dinitro ortho cresol1 7#c-;hydroxy #c1e-;dinitro toluene71 melting at #hc4e-hd uncorr4 7,nevile and ,winther gave #he for the pure substance47 ,this dinitro compound was obtained in nearly quantitative yield indicating that the diazo compound was presumably pure4 ,,physical ,,properties ,,of ,,the ,,diazo ,,compound ,it is almost insoluble in water1 and is insoluble in denatured alcohol and ether4 ,it is a white solid which can be dried and kept without apparent decomposition2 it gradually turns pink when exposed to the light for several days1 so is kept in a brown bottle if not required for immediate use4 ,it does not explode when struck with a hammer1 but deflagrates violently if a flame is brought near or if heated on porcelain4 ,,decomposition ,,of ,,the ,,diazo ,,compound 7#a7 ,with n-,butyl alcohol in the presence of sodium carbonate4 ,a portion of the dry diazo compound was placed in a flask connected with a reflux condenser1 and solid sodium carbonate and n-butyl alcohol added4 ,no reaction took place at ordinary temperature so heat was applied4 ,decomposition started at #fe and evolution of hydrogen proceeded evenly and smoothly until all the diazo compound had disappeared4 ,the alcohol1 at first colorless1 became an orange and finally a brown color4 ,the solution was then refluxed an hour to ensure complete decomposition of the diazo compound4 ,the smell of an aldehyde was evident indicating that the hydrogen reaction was taking place2 the solution was tested with ,schiff's reagent and with ammoniacal silver nitrate with distinct positive results in both cases1 showing aldehyde was present4 ,the alcoholic solution was filtered from the sodium carbonate remaining1 and the alcohol distilled off on an oil bath4 ,a yellowish-orange porous solid was left in such a small amount that no derivatives could be made and studied4 ,it was free from the diazo compound1 shown by its giving no color with an alkaline solution of ,h acid4 7#b7 ,with n-,butyl ,alcohol alone4 ,the previous experiment showed that n-butyl alcohol would decompose the diazo compound in the presence of sodium carbonate and replace the amino group by hydrogen1 so this time a decomposition with the alcohol alone was tried4 ,decomposition took place evenly and smoothly as before at the same temperature1 and the solution became a clear brownish-orange4 ,aldehyde was given off and tested for as before with positive results4 ,the alcohol was removed by distillation and a thick brownish syrupy liquid was left4 ,this was easily soluble in water1 so was dissolved1 filtered1 and the solution used in the following experiments4 ,at this point it is similar in every way to the solution obtained by ,griffin 7loc4 cit47 from the diazo compound of para toluidine meta sulphonic acid4 ,subsequent preparations of this syrup were made in the above way with similar results in every case4 ,the only precaution to be observed is that no part of the flask containing the reaction mixture be allowed to become too hot as the diazo compound is then decomposed violently leaving a grayish ash4 ,a ,,study ,,of ,,the ,,solution ,,obtained ,,by ,,the ,,decomposition ,,of ,,the ,,diazo ,,compound ,the syrup which remained after distilling off the n-butyl alcohol was a thick brown viscous fluid in all cases4 ,it has an acid reaction and is completely soluble in water4 ,on testing it showed the presence of sulphur in quantity and the absence of nitrogen4 ,some was dissolved in water1 filtered1 and evaporated on the water bath4 ,after its volume had been considerably reduced it turned a very dark brown1 then blackish1 and smelled very tarry4 ,it did not crystallize at all1 finally becoming very black4 ,to a drop on a watch glass1 a drop and then an excess of concentrated hydrochloric acid was added but with no apparent result4 ,another portion of the syrup was dissolved in water1 boiled with purified animal charcoal1 and filtered4 ,the filtrate was colorless4 ,it was then evaporated on the water bath and solidified completely4 ,some of this solid was ignited and a white ash was left2 had it been a sulphonic acid there would have been no residue4 ,a qualitative analysis of the ash was made and much phosphate and calcium found present2 therefore this solid was presumed to be a mixture of calcium phosphate from the animal charcoal and perhaps the calcium salt of the sulphonic acid4 ,this showed that animal charcoal could not be used for purposes of purification4 8,activated charcoal0 has been advocated for decolorizing solutions as well as for absorbing toxic gases2 the author had become acquainted with this material while in the ,chemical ,warfare ,service1 and had obtained small samples of 8,dorsite0 and 8,carbonite04 ,some of this was powdered and the brown solution boiled with it until most of the color was removed4 ,the solution was then filtered and evaporated on the water bath2 a white crystalline solid was again left4 ,investigation of the activated charcoal showed that concentrated acids extracted some substance which was thrown down in a flocculent white precipitate on making alkaline with ammonia4 ,therefore another sample of the activated charcoal was boiled with concentrated nitric acid1 filtered1 and the charcoal washed free from acid2 this sample did not decolorize well4 ,a sample of a specially prepared charcoal for decolorizing purposes manufactured by the ,barneby-,cheney ,co4 was obtained and tried1 but was unsuccessful2 the color was not removed4 ,infusorial earth1 kiesel guhr1 and 8,sil-o-cel0 were also tried unsuccessfully2 ,fullers ,earth made a very clear solution but no color was removed4 ,some of the brown viscous solution was dissolved in water1 the solution filtered and evaporated to a constant volume 7estimated when no more vapor could be seen to condense7 under diminished pressure 7water pump7 until it became more brown4 ,it was then allowed to cool1 and dry hydrochloric acid gas passed in1 first to expel all air or other vapor present1 and then under pressure4 ,the solution became slightly warm4 ,a few fine crystals formed on the interior surface of the flask where some of the solution had spattered during distillation1 which however were quite indistinct and seemed to be in the center of a drop of water or solution4 ,on allowing the flask to stand over night the whole of the solution seemed to be filled with crystals4 ,they were too indistinct to enable their crystalline form to be determined so an attempt was made to remove some for examination4 ,as soon as they came into contact with the air they disappeared and left a very viscous solution1 indicating that they are very hygroscopic4 ,a small amount was removed and placed in a dish in a vacuum desiccator which was evacuated and left for a month1 with periodical examinations4 ,no solid appeared at any time4 ,this is as far as the investigation has been carried at the present time1 ,april twenty-fifth1 but its study is being continued4 ,,conclusion ,the results of this investigation may be briefly summarized as follows3 7#a7 ,ortho toluidine may be easily converted into its sulphonic acid in which the sulphonic acid group is in the position meta to the methyl group4 7#b7 ,para toluidine is converted into a mixture of two isomeric sulphonic acids of which the one with the sulphonic acid group in the position meta to the methyl group is obtained in a ten per cent yield4 7#c7 ,ortho toluidine sulphonic acid may be easily diazotized using sodium nitrite and concentrated hydrochloric acid4 7#d7 ,the diazo compound is very stable4 7#e7 ,the diazo compound is easily decomposed with n-butyl alcohol1 the hydrogen reaction taking place4 ,,bibliography ,in addition to the references made in the thesis itself the following authorities have been consulted for the theoretical discussion3 ,beilstein1 ,f4 ,c41 8,handbuch der organischen ,chemie0 #ahhf-ahij4 ,voss1 ,hamburg4 ,victor von ,richter1 8,organic ,chemistry0 ,trans4 #ahii-aijj4 ,p4 ,blakiston's1 ,philadelphia1 ,pa4 ,b4,p4,l4 #cigd4afj ,meyer and ,jacobson1 8,lehrbuch der organischen ,chemie0 #ahic4 ,veit ,co41 ,leipzig4 ,b4,p4,l4 #cigc4adc ,transcriber's ,note3 ,table of contents added by transcriber4 ,obvious printer errors corrected silently4 ,inconsistent spelling and hyphenation are as in the original4