ORGANIC ANALYSIS 145 ORGANIC ANALYSIS. Interpretation of Coal Analysis. E. G. Bailey. (Ann. Meeting, Inter- national Railway Fuel Assoc.; through J . Inst. Brewing, 1917, 23, 133-138.)-The usual analysis of coal gives the percentage of moisture, volatile matter, fixed carbon, ash, and sulphur, in addition to the calorific value. The calorific value is perhaps the most important factor, but if the others are not taken into account erroneous conclusions may be dmwn. The non-combustible matters present have such it modifying influence that not infrequently the better of two coals, judged only by their calorific values, proves the worse in practice.The author discusses the influence of various factors, determined by analysis, on the actual stoking value of coal. The real basic impurities in coal, from the point of view of generation of heat, are oxygen, nitrogen, and ash.Sulphur is generally classed as an impurity because its heating value is so low that it does not compensate for the detrimental qualities of this constituent. In the accompanying table the amounts of the constituent elements present in the volatile matter are shown. The percentage of volatile matter in a coal is not a measure of the value of the coal, for much depends on the nature of the volatile matter and how much of it is combustible. Moreover, in the combustible matter itself the proportion of available hydrogen to carbon affects the heating value.ANALYSIS or A TYPICAL WEST VIRGINIA COAL. - aonstituents per Cent, of Coal. Moisture 2.01 { Y:~;}Z.O~ water .. H 4.86 5.38 water . . 0 4*78}4-26 available H 37.31 C 26.65 . . .. .. N 0.23 . . .. .. S 0.79 . . .. .. C 49.18 . . .. .. S 1.75 . . .. .. Ash 8-55 .. .. .. .. Volatile Fixed carbon 52.13 .. . . i .. .. .. .. .. . . .. .. .. .. B.T.U. by calorimeter B.T.U., per Pound. None None 62,000 14,500 None 4,050 14,500 Xone 4,050 None .. .. Calculated B.T.U., per Pound of Coal.- - 2,641 3,464 32 7,131 71 - - 13,339 13,811 The percentage of moisture in coals varies widely according to their character. It is much higher in lignite and sub-bituminous coals than in bituminous or semi-146 ABSTRACTS OF CHEMICAL PAPERS bituminous kinds. Anthracite coal, on the other h a d , has a sLightly higher per- centage of moisture than semi-bituminous coals. Many people have considered that the percentage of moisture was such a variable quantity, depending on weather con- ditions, etc., that true comparison could only be obtained on a dry basis, and they therefore reduce all analyses to this basis.This is Skely to lead to very erroneous conclusions. For instance, if Illinois coal, which normally contains about 12 per cent. of moisture, is compared on a dry baais with bituminous coal from the Pittsburg or West Virginia district, which contains usually about 3 per cent.of moisture, the former will appear about 9 per cent. better than it should do. In order to get a uniform basis of comparison, it is right to compare qifferent shipments of coal from the same region on a dry basis, but coals from Merent districts and of different characters should be compared on a basis which takes into account the normal, moisture-contents fairly representative of the different districts.A coal which normally has a high moisture-content usually has a relatively large proportion of its volatile matter in the form of combined water, and this water is as unproductive of heat as the ordinary moisture of the coal.The only practical meam of allowing for the effect of this combined water is to determine the calorific value of the coal, for such coals have low calorific values per pound of matter other than moisture and ash. It almost invariably contains alumina, silica, iron, lime, magnesia, titanium, alkalis, etc. The relative proportions of these constituents may vary widely in different coaJs, and their effect upon the behaviour of the coal is determined by such complex laws that it is practically impossible to use the analytical data as a trustworthy means of determining the character of the ash for comparative purposes.An ash which does not clinker gives little trouble, and is not much, if any, more detrimental than so much moisture. It is merely an inert substance that produces no heat.It does not seriously obstruct air-passages, and can easily be shaken through the grate. But an ash which melts into a clinker is more difficult to get rid of, and it may adhere firmly to the bars and obstruct the air so completely that the heat of the fuel-bed causes the bars to burn. Hitherto practically the only .method of ascertaining how the ash of coal would behave was by an actual trial; but such trials do not always afford trustworthy means of comparison, for some stokers make more clinkers than others from the same coal.A study of this phase of the fuel problem some years ago led the author to conclude that everything depends on the ternperatur;! at which the ash fuses and the temperature to which it is actually subjected in practice.Some coal ash haa such a high temperature of fusion that, there are prtlctically no fuel-bed con- ditions which will produce troublesome clinker from it. Another ash with a slightly lower fusing temperature will form a porous, spongy clinker which does not seriously obstruct the flow of a x and is not difficult to remove. An ash of still'lower fusing temperature-e.g ., 2100" 'F .-will not only become melted under average conditions, but will be heated several hundred degrees above its melting-point, in which case it runs down and spreads out in a thin sheet over the grate bars.When a coal is burned the ash is not entirely liberated until it reaches the lower The most important impurity in coal is the ash.ORGANIC ANALYSIS 147 part of the fuel-bed, where the incoming air maintains a lower temperature than obtains in the zone 4 to 6 inches above the grate.So it is often possible to get satis- factory results from a coal of which the ash fuses a t 2300" P., although the tempera- ture of the fuel bed may be 2500" F. Some clinker will, of course, be formed, but it is not of an extremely objectionable character if the firing is properly done; it accumulates gradually, and is more or less open and does not obstruct the air beyond the critical limit.But if another stoker should handle the same coal, differently slicing or working the fire and causing the ash, which has already been liberated from the coal in the lower and cooler part of the fuel-bed, to be thrown up again into the hotter zone, it will melt into a very fluid mass and spread out over the grates in a thin sheet, obstructing the air to a serious extent.It is frequently considered that the percentage of sulphur is a true indication of the clinkering property of a coal. The estimation of sulphur in coal originated with the steel-works chemist, for in his case sulphur is extremely detrimental, but for steam coal it is of minor importance. It is true that in some coalfields the clinker- ing property of coal from different mines does vary to some extent with the sulphur- content, but the constituent which really affects the clinkering property is iron, and this usually increases or decreases with the sulphur.There are so many excep- tions to the rule connecting with sulphur-content, or even the iron-content, with the clinkering property of coal, that dependence upon either is apt to lead to erroneous conclusions.One of the worst clinkering coals in the United States has a sulphur- content below 0.25 per cent. Several of the largest stationary power plants in America make determinations of the fusing temperature of the ash, in addition to the regular analysis of each shipment of coal.This determination has not yet been standardised. in the laboratory to the same extent as the determination of calorific value and other factors. In the author's opinion the method which will ultimately prove most suitable for this determination will be one that adheres most closely to practical conditions by reproducing, as far as possible, the conditions which obtain in the fuel-bed.Colour Reactions of Aromatic Aldehydes. P. Pooth. (Xchweix. Apoih. Zeit., 1916,541,377-382 ; through J. Chem. Soc., 1917,112, ii., 52.)-The condensation of aromatic aldehydes with sulphonated aromatic amino-compounds leads to the formation of characteristic, distinctly coloured azomethines, which can be employed in the identification of aldehydes.Aromatic aldehydes yield more distinct colora- tions with naphthionic than with sulphanilic acid; in most cases the azomethine separates directly on cooling. The test is performed as follows: 3 to 4 G.C. of an aqueous solution of sodium sulphanilate or naphthionate (10 per cent .) are heated in a porcelain dish on the boiling-water bath; a boiling alcoholic solution of the aldehyde is added, which causes the appearance of a pale yellow t o red coloration, and the solution is evaporated to dryness, the colour generally being deepened thereby.Before evaporation, a few drops of the solution are removed, diluted with water, cooled, and treated with a few drops of dilute sulphuric acid; in many cases the colour is deepened, in others completely changed. Certain of the reaction products, parti-148 ABSTRACTS OF CHEMICAL PAPERS cularly those derived from nitro-aldehydes, are sensitive to light.obtained from substituted aldehydes are less stable. The products Spontaneous ignition Temper- atures of Liquid Fuels for In- ternal Combustion Engines. H. p l ~ c Moore. ( J . Soc. Chem. Id., 1917, 36,109-112.)-The determination of this constant is important, both for engines which receive the fuel and air before the compression stroke (petrol engines) and for engines which compress the air alone and inject the fuel into the cylinder about the end of compression (Diesel engines). For use with the first t,ype of engine, the constant should not be too low, or pre-ignition can only be avoided by the use of relatively low compression T H E R M ~ : PLUG pressures and consequent loss of effi- ciency.Diesel engines, on the other hand, depend on spontaneous igni- tion of the charge, and this should take place at a reasonably low temperature, or the necessary pres- sures may be so high as to intro- duce mechanical difficulties. Holm has described an apparatus (Zeitsch. angew. Cfiem., 1913, 273) for deter- mining spontaneous ignition temperatures, but the author found this insufficiently delicate for his researches with Diesel engines, and in consequence he designed the apparatus now described.It consists of a diffusion block of mild steel bar of 4 inches diameter, 3) inches deep, the base being turned as illustrated to afford greater heating surface. The upper end of the bar is machined t o fit exactly the platinum crucible, which is 35 mm.in diameter at the top. A screwed-on cover protects the upper end of the crucible from draughts. The cover is provided with two holes, one for air inlet and one for oil inlet. The air is preheated to the temperature of the experiment, passing through a, thin copper coil situated in a chamber inside the block. A ther- mometer and a thermo-couple pyrometer are fitted into the diffusion block as close as possible to the base of the crucible, and show the temperature of the experiment.Air is passed through the apparatus at the rate of three bubbles a second, a sulphuric acid wash-bottle enabling one t o count the bubbles. When the temperature of the block is constant a t a desired temperature one drop of the fuel under examination is allowed to fall through the hole in the centre of the cover of the instrument. If the temperature is higher than the ignition point an explosion occurs one second after the introduction of the oil.By repeating the experiment the lowest ternpera-ORGANIC ANALYSIS 149 ture at which ignition takes place is rapidly determined. The results obtained by different experimenters, using the same instrument, agree within 3” C .G . C. J. Impure Picric Acid as a Source of Error in Creatine and Creatinine Estima- tions. 0. Folin and E. A. Doisy. ( J . Bi02. Chem., 1917, 28, 349-356; through J . 806. Ohem. I d . , 1917, 36,.235.)-Attention is directed t o the fact that certain specimens of picric acid, particularly those sold in the wet condition, contain some impurity, and, owing to the more or less intense coloration they give when neutralised with sodium hydroxide, are quite unsuitable for use in the colorimetric determination of creatinine.When20 C.C. of saturated picric acid solution are treated with 1 C.C. of 10 per cent. sodium hydroxide solution, the coloration ob’tained and observed after fifteen minutes should be not more thanabout twice as deep as the colour of the saturated picric acid solution.Method of Steam Distillation for the Determination of Volatile Fatty Acids, including a Series of Colorimetric Qualitative Reactions for their Identification. D. C. Dyer, { J . Biol. Chem., 1917, 28, 445-473; through J . SOC. Chem. Id., 1917, 36, 236.) -In the steam distillation method described, the volume of the solution from which the acids are distilled is maintained constant at 150 c .c.throughout the distillation. Under these circumstances the distilling con- stants (proportions distilling over in succeeding fractions) me indicated by straight lines when plotted on a simple logarithmic chart, whilst the distilling variables of mixtures of these acids are indicated on the same chart by curved hex.With neighbouring acids the curves are very flat, and the further the acids comprising the mixture are removed from each other (in the series) the greater will be the curvature of the graph. The lowest acid of the series in a mixture may be identified with certainty, since the line representing the distilling constant will eventually reach a point where it will begin to run parallel to some straight line on the chart which represents that acid.This same point indicates where the other acid of the mixture has run out, and the probable nature of this second acid may be found by reference to a table which is given. The qualitative tests described for the identification of the volatile acids depend on the different solubilities of the iron and copper salts of the acids in smyl alcohol, ether, and petroleum spirit.Duclaux’s Method for the Estimation of Volatile Fatty Acids. F. W. J. Boekhout and J. J. 0. de Vries. (Centr. Bakt. Par., 1916, ii., 46,505-513; through J . Chem. Soc., 1917,112, ii., 60.)-The authors have investigated Duclaux’s method (Ann. de Z’lnst. Pastew, lS95), and confirm the figures given in his tables for formic, acetic, and propionic acids; in the case of butyric and valeric acids, the results obtained were somewhat different from those recorded by Duclaux.It is shown that if the differences between the quantities of acid found in each successive fraction of the distillate are calculated into percentages of the acid remaining in the flask at the commencement of the distillation of each fraction (this quantity of residual acid being first calculated into 110 C.C.of the solution), a constant number is obtained for each fraction, and is the same for each individual acid. This number is 3.5 for150 ABSTRACTS OF CHEMICAL PAPERS formic acid, 5-9 for acetic acid, 11.8 for propionic acid, 19-1 for butyric acid, andl 26.0 for valeric acid. This method may be applied to the analysis of mixtures of the acids.Gasometrie Estimation of Amino-Nitrogen in Worts, Extracts, etc. R. Emslander. (Zeitsch. ges. Brauw., 1916, 39, 265-267; through J . Inst. of' Brewing, 1917,23, 116.)-The method described, like that of van Slyke, is based on the measurement of the volume of nitrogen produced by the action of nitrous acid on the liquid under investigation, the reaction involved being represented by the equation- R*NH, + HNO, = R-OH + q0 + N,.The apparatus consists of a gas burette having alternative connections by a three-way cock a t its upper end with a gas-evolution bottle on the one hand and a Hempel gas pipette containing a 2-5 per cent. solution of caustic soda saturated with potassium permanganate on the other. The burette itself is filled with a.concentrated solution of ferrous sulphate, and is provided with a levelling vesseL in the usual way. The gas-evolution bottle, 50 C.C. capacity, has a stopper fitted with (1) a capillary tube for connection with the burette, (2) it smell tap-funnel con- taining octyl alcohol (to prevent frothing), (3) a large tap-funnel, and (4) a burette containing the liquid to be analysed.The bottle is first filled with 40 C.C. of sodium nitrite solution (3 parts of sodium nitrite to 10 parts of water) and 10 C.C. of glacial acetic acid. Oxides of nitrogen are evolved, and the stopper is a t once fixed in the bottle, the cock of the large tap-funnel being left open so that the evolved gas forces.the liquid up into this funnel. When the bottle is about half full of gas, communica- tion is opened with the gas burette, and the nitrite mixture is allowed to flow from the tap-funnel into the bottle until the latter is again quite full. The displaced gas,. thus transferred to the burette, is afterwards ejected from the latter by raising the level of the ferrous sulphate solution until the burette is again filled with liquid..In this way all air is swept out of the apparatus. All connections except that between the bottle and the gas burette having been closed, the liquid to be analysed is run into the bottle from the burette containing it. If frothing occurs, a little octyl alcohol is also run in. The evolution of gas, assisted by frequent shaking, is allowed to proceed for five minutes, in which period all the nitrogen is evolved.The whole of the gas in the bottle is then driven over into the burette by running nitrite mixture into the bottle from the tap-funnel, The greater part of the oxides of nitrogen present in the gas mixture in the burette is absorbed by shaking with the ferrous sulphate solution. The residual gas is then driven over into the Hempel pipette and shaken vigorously with the alkaline per- manganate solution, and the pure nitrogen remaining is again transferred to the burette and measured with the usual precautions; 1 C.C.of nitrogen (corrected or the tension of aqueous vapour) at 0" C. and 760 mm. pressure corresponds to 0.6253 mgrm. of amino-nitrogen. Estimation of Total Nitrogen. E.Justin-Mueller. (Bull. Sci. Pharmacol., 1916, 23, 167-169; through J . Chem. Xoc., 1917, 112, ii., 39-40.)-When organic substances are destroyed in the presence of mercury according to Kjeldahl's method,ORGANIC! ANALYSIS 1.51 a portion of the ammonia remains combined in the form of mercury ammonium compounds, and is not estimated by the method of Ronchhse (ANALYST, 1907,32, 303).Low results are also obtained after addition of sodium sulphide or hypo- phosphite, but, according to the author, the results are accurate when potassium arsenite is used to decompose the mercury-ammonium compounds. The estima- tion is performed in the following manner : Urine (10 c.c.) is heated with con- centrated sulphuric acid (5 c.c.) and mercury (about 0.1 grm.).If the urine contains sugar the quantity of acid is increased in the ratio of 10 per cent. of the sugar content. As soon as the solution becomes colourless the heating is discontinued, the solution cooled, and diluted to 50 C.C. with water. Five C.C. of the dilute solution are mixed with 10 C.C. of the arsenite solution and 5 drops of phenolphthalein, and neutralised by sodium hydroxide (10 per cent.) ; the precipitate is allowed to settle for a few seconds, filtered, the residue washed three times with water, and the ammonia estimated in the filtrate by the formaldehyde method of RonchAse.The potassium arsenite solution is prepared by dissolving arsenioug oxide (5 grms.) with the help of potassium hydroxide (11-20 grms.) or N/l potassium hydroxide (200 c.c.), and making up the,solution with water to 1,000 C.C.Estimation of Total Sulphur in Leather. L. E. Levi and A, C. Orthmann. (Chem. News, 1917, 115, 55-56.)-The sulphuric acid is precipitated as barium sulphate after the organic matter has been destroyed by boiling the leather with a mixture consisting of potassium dichromate 50 grms., water 150 c.c., and concentrated hydrochloric acid 50 C.C.One grm. of the fat-free leather is heated to boiling with 20 C.C. of the dichromate mixture, 10 C.C. of hydrochloric acid are then added, and the heating continued until all organic matter has been destroyed. The solution is now boiled for three minutes, 50 C.C. of water and 5 C.C. of alcohol are added, the mixture is boiled until the dichromate is reduced and the alcohol and aldehyde ex- pelled, and the sulphate then precipitated by the addition of barium chloride solution.If the leather contains talc or other insoluble substance the solution must be filtered before the barium chloride is added. The results obtained by the method agree with those found by the bomb, the nitric acid, and the sodium carbonate methods. w. P. s. Identification of Phenols.E. E. Reid. (J. Amer. CAem. XOC., 1917, 39, 304.)-An improvement on the Schotten-Baumann reaction as a means for identify- ing the phenols is the formation of their p-nitrobenzyl ethers, which crystallise readily and have convenient melting-points ; p-nitrobenzyl bromide reacts readily with salts of many acids to form esters, and this same reagent combines with the sodium or potassium phenolates to form the ether- pNO,C,H,CH,Br + NaOC,H, = pNO2C,H4CH2OC,H, + NaBr.The reaction is a very clean one, and a pure product is obtained directly; the chloride should work in most cases as well as the bromide. Into a 100 C.C. flask are measured 25 C.C. of N/5 alkali in 95 per cent. alcohol, and to this is added a moderate excess of the phenol; usually this will be about 1 grm.152 ABSTRACTS OF CHEMICAL PAPERS for phenols of molecular weight under 200.To this solution is added 1.0 grm. of p-nitrobenzyl bromide, and the whole is heated on the steam-bath under a reflux condenser for one hour, the progress of the reaction being shown b'y the precipitation of sodium or potassium bromide. About 5 or 10 C.C. of water are then added, which dissolves the bromide, and the solution is quickly cooled whilst vigorously shaken t o cause the formation of small crystals.The solution should be made just alkaline with caustic soda during the separation of the crystals, to prevent the separation of the excess of phenol, which might con- taminate the p-nitrobenzy ether; this is filtered off, dissolved in boiling 95 per cent.alcohol, and again thrown out by the cautious addition of water, The following ethers have been made: Phenyl p-nitrobenzyl ether [C6H,0CH,C,H,N0,], m.-pt. 91" C. 0-Cresyl p-nitrobenzyl ether [o-CH3C,H,0CH,C,H4X02], m.-pt . 89.7" C. m-Cresyl p-nitrobenzyl ether [rn-CH,C,H,OCH,C,H,NO,], m.-pt. 51.0" C. p-Cresyl p-nitrobenzyl ether ~-CH,C,H,0CH2C,H4N02~, m.-pt. 88" C.Thymyl p-nitrobenzyl ether [CH,(C,H,)C,H, OCH,C,H,NO,], m.-pt. 85-5" C. Eugenyl p-nitrobenzyl ether [C,H,(OCH,)C,H,OCH,C,H,NO,], m.-pt. 53.6" C. Vanillyl p-nitrobenzyl ether [CH30(CHO)C,H,0CH,C,H,N0,~, m.-pt. 124-5" C. H. F. E. H. Analysis of Acetate of Lime. S. H. Collins. ( J . SOC. Chem. I d . , 1917,36, 68-7O.)-This process is described in connection with a portable apparatus for the distillation of wood. Two grms. of the acetate are distilled with 15 C.C. of syrupy phosphoric acid in a large flask into which water is admitted from a Marriott dripping-bottle at, the rate of about 4 drops per second. Both the distillation flask and the receiving flask are provided with soda-lime tubes to prevent any admission of carbon dioxide from the air. The liquid is distilled a t such a speed that about 50 C.C. are always present in the distilling flask, and the distillate is received in 25 C.C. of N/1 sodium hydroxide solution, which is subsequently titrated with N/5 sulphuric acid, with phenolphthalein as indicator. In the c&se of pure acetates the whole of the acid distils in 300 c.c., but for very crude products, which contain a larger pro- portion of =ids of higher boiling-point, it may be necessary to distil as much as 1,200 C.C. In any case it is advisable to continue the distillation until an extra 100 C.C. has been obtained, after all acid has apparently been driven over. An addition of 1 C.C. to the amount of sulphuric acid used in the titration is made as a oorrection for the alkali neutralised by.the carbonic acid in the distilled water introduced into the flask. C. A. M.