IV. On Malic Acid and the Changes widergone by its Salts at Ph. D. High Temperatwes. By ROBERTHAGEN Read June 1 1841. AFTER the publication of Mr. Graham’s observation that phosphoric acid in its different states possesses the pro- perty of combining with one with two and with three atonis of base respectively it was discovered by Liebig that the same law holds good in part with many orgnnic acids; some of these acids requiring two and some three atoms of base to form neutral salts. The hydrates of each acid contain a corresponding number of atoms of basic water which cannot be removed without the decomposition of the acids them- selves. These chemists showed that though a salt of any acid with magnesia or with oxides isomorphous with it pos- sessed the power of combining with a potash salt of the same acid and forming a double salt such as the sulphate of mag-nesia and potash that is not ground for doubling the atomic weight of the acid or for viewing it as bibasic.They proved at the same time that a monobasic acid is incapable of forming a double salt with two isomorphous bases. The proportion of base which unites with a poly-basic acid is constant generally either two or three atoms. In the memoir on organic acids hy Liebig here alluded to he had made it iiot improbable that malic acid is bibasic. At his suggestion 1have made several analyses of its various salts which form the subject of this paper. Malic acid was first discovered hy Scheele in the juice of the apple; it was again discovered by Donovan in the juice of several plants and described by him RS a new acid.The identity of the acid of Donovan with nialic acid was proved by Braconnot. This acid has been most fully described by Liebig. It has also been partially examined by Pelouze Braconnot and Richardson. The malic acid used in the present investigations was pre-pared from the expressed juice of the berries of the Sorbus occupuria or Service tree in the following manner. The ex- pressed juice was mixed in a copper pan with fine!y divided is therefore somewhat too high and it contains more than one volunie of oxygen ;thus it is clear that the atomic weight of carbon as calculated from this is also too high That calciilated from his specific gravity at the pressure of one-third of an atmosphtre is 75-7.He has 1syet however only made three weighings which he considers as little more than intro- ductory experiments of practice. I shall be present tomorrow at the fourth determination.” Lh. Robert Hagen on Mdic Acid and levignted hydrate of lime care being taken not to satu-rate the fluid completely but to allow it to remain sensibly sour. Being placed on the fire it was made to boil for some hours during which time it gave off a peculiar pungent vapour which strongly affects the eyes. By degrees neutral malate of lime precipitates and may be removed with a ladle. By continued boiling more of the salt is obtained. When no more fhlls the vessel is removed from the fire arid allowed to cool when a little more is precipitated.We must take care in the beginning not to saturate the expressed juice en- tirely with lime or so much colouring matter falls with the malate of lime as to render the acid impure. The neutral malate of lime thus obtained is dissolved in dilute nitric acid (1 part acid to 10 of water) filtered and evaporated; upon cooling acid malate of lime crystallizes out in perfectly colour-less crystals. It must be well washed with cold water again dissolved in boiling water and precipitated by acetate of lead. The lead salt is decomposed by sulpliuretteti hydrogen and the malic acid obtained pure by evaporation. Malic acid forms with bases two neutral salts one of which becomes anhydrous when dried at loo3C. while the other still retains water at that temperature.It possesses decided bibasic properties and the hitherto receiwd atomic weight is necessarily doubled. The following salts have been examined :-MALATES OF LIME. a. Neutral anhydrous Mulate of Lime. C,H,O,+ ZCnO or M2uau. This salt is obtained by saturating a solution of malic acid with liine water. It is a crystalline powder perfectly insoluble hot and cold water. 0.489gramme of this salt gave 0.319 sulphate of lime or 32*1S8 per ceut. lime. This gives for the atomic weight of the salt the number 2212.40. Calculated. Found. 1 equivalent of Malic Acid 1461.39 2 equivalents of Lime . . . 712.04 67.24 32-76 67.81 32.18 b. Neutral hydrated Malate of Lime. -M ~CaO+5aq. M 2 Ca 0+ 4 aq. ( loooC.) If acid malate of lime is saturated with potash soda or ammonia and the solution evaporated at a gentle tempera- ture we obtain instead of it double salt malate of lime with 5 equivalents of water in hard shining crystals.When heated 30 Dr. Robert Hagen on Malic Acid. to loooC. this salt is converted into a porcellanous mass and is found to have lost one atom of water. At 150' C. it becomes quite anhydroiis. Of the salt in its first state of hydration 0*422gramme dried at the temperature of the atmo-sphere gave 0-2655 sulphate of lime or 26*113per cent. lime which makes the atomic weight of the salt 2725.0 and gives the following composition :-Calculated. Found. 1 eq. Malic Acid 1461.39 533.44 2 ... Lime . . . 712-04 26*03 26*113 5 ...Water . . 562*40 20*53 -I__. 2735.83 100*00 Of the salt dried at 100' :-(1). 0'6 135 grarrime gave 0.4045 sulphate of lime = 27*383 per cent. lime; and consequently the atomic weight 2600*0. (2). 0.3660 gramme gave sulph. lime 0.241 or 27-344 per cent lime. (3). 0.335 salt gave 0.353 sulphate lime and consequently the atomic weight 2598%. These give- Calculated. Found. 1. 2. 3. I Malic acid 1961.39 56.71 2 Lime . ; . 712.04 27.14 27.38 27-39 27.40 4 Water. . . 449.92 17.15 2623'85 The previous analyses of the lime salt dried without heat shows the necessity of doubling the atomic weight of the acid as otherwise we should be obliged to give it the formula C4H2O4Ca 0 + 2; aq. ; which is at variance with the atomic theory.ACIDMALATE OF LIME &f Ca 0H*0 + 6 aq. This salt is obtained when neutral malate of lime is dis- solved in nitric acid. It crystallizes in large transparent octa- hedrons. Dried at 100' C. it loses water and is converted into a viscid stringy mass. 0-706 salt gave 0*2345sulphate of lime or 13*794per cent. lime ; atomic weight 2585'8. Calculated. Found. 1 atom Malic acid 1461039 56*10 1 atom Lime . . . 356.02 13'67 13'79 7 Water . . . 787'56 30*23 2604.77 Dr. Robert Hagen on MnZic Acid. Richardson and Merydorf concluded the formula of this salt to be aCa 0 H20 + 8 aq. MALATES OF MAGNESIA. a. Neutral hydrated Malate of Magnesia. -M 2MgO + 10aq M 2 MgO + Zaq (IOO°C.). This salt is obtained by boiling magnesia in a solution of malic acid and crystallizing.It loses 8 atoms of water by 100' c. 0*5505 salt gave 0*2708sulphate of magnesia equivalent to 16.713 per cent. of magnesia; and makes the atomic weight 3091*4. Calculated. Found. 1 eq. Mslic acid 2 ... Magnesia.. 10 ... Water. . . 1124*8 146139 ,516"iO 16.66 47.09 36*55 16-713 3102.89 Of the salt dried at 100' C. 0.466 gRve 0*109 sulphate of magnesk equivalent to 23.390' per cent. magnesia. Calculated. Found. 1 at. filalic acid 1461.39 66'34 2 ... Magnesia . 516*70 23'45 23.39 2 ... 'Water . . 224.96 10'51 2209*05 This salt was also analysed by Professor Liebig with the same result. -b. Neutral anhydrous Malate of Magnesia. M 2 Mg 0. This salt is obtained by precipitating a saturated solution of the former salt (a.)with alcohol and drying at 100' C.0*344salt gave 0*0935magnesia equivalent to 26'945 per cent. ; atomic weight 1906*88. Calculated. Found. 1 atom &lic acid 2461.39 73%3 2 atoms Magnesia 5 16-70 26.12 26*94 1978'09 ACID MALATE OF MAGNESIA.-Mg 0 H20 + 3 aq M Mg 0H20 + aq (100'). Obtained by dividing and saturating one half of the malic acid with carbonate of magnesia and evaporating to crystal- 32 Dr. Robert Hagen on Malic Acid lization. It ioses 2 atoms of water by 1000C. ; at a higher temperature it melts. 1.1755 salt gave 0-1405 magnesia equivalent to 11*952 per cent.; and for the atomic weight 2161*.5. Calculated. Found. 1 atom Malic acid 1461039 6$*36 I ...Magnesia "LS*35 11*91 11.952 4 atoms Water ... 449.91 20.74 21 Gg466 Of the salt dried at 100' C. 0.698 gave 0-0795magnesia or 13.294 per cent.; atomic weight 1943.0. Calculated. Found. 1 eq. Malic acid 1461.39 75'147 1 ... &Iagnesia 258.35 I W85 13*294 2 ... water . . 224.96 1 1 *.56S ~ ~~ 1944-70 MALATES OF ZINC. a.Neutral Salt. --M 2ZO+6aq &I 2 2 0 + -(1000 C.). Is prepared by digesting carbonate of zinc with malic acid at a temperature not above 3OoC. Dried at looo C. it be-comes anhydrous. Of this salt O*4570 gave 0'2935 sulphate of zinc or 32.179 oxide of zinc making the atomic weight 3127%; the calcu- lated one being 3142.77. 0.695 of the salt dried at 100' C. gave 0.566 sulphate of zinc or 40'302 oxide of zinc; making the atomic weight 2463.6; the calculated is 2467.6.ACIDMALATE OF ZINC. a.2 0H 0+ 2aq. Prepared by adding excess of malic acid to the neutral salt. 0.190 of this salt gave 0.082 sulphate of zinc or 21*343 per cent. of oxide of zinc; the atomic weight deduced from which is 2351-7. The coniposition of the salt is therefore -CalcuI ated. Found. 1 eq. Maiic acid . 1461*4 63'480 1 ... Oxide of zinc 5039 21.861 21'349 3 ... Water . . 337*4 14*659 2302*0 Braconnot analysed this salt with the same results. Dr. Robert Hagen on Ma& Acid. BASIC OF ZINC. MALATE If malic acid is long boiled with excess of carbonate of zinc there falls down a sandy powder; of this salt dried at IOOO (1.) 0.3935 gave 0.178 or 44-66 per cent.of oxide of zinc ; atomic weight 22595. (2.) 0.255 gave 0.224 sulphate of zinc or 44.015 per cent. of oxide of zinc ; atomic weighl 2286.8. (I.) 0'474 burnt with oxide of copper gave O*lOf5water and 0*329carbonic acid. (2.) 0.5510 gave water 0'1335 and 0.3835 carbonic acid. This salt is therefore composed of Calculated. Found. 12 at. Carbon . . . 917.22 20.19 19'191 19'24 9 ... Hydrogen. . 112.32 2.47 2.52 2.69 15 ... Oxygen. . . 1500*00 33.03 33'62 84.04 4 ... Oxide of zinc 2012.9 44.31 44-66 44'015 4542*4$ Heated to 100' C. it lost 4 atoms of water; and 0*420 gave 0*411 sulphate of zinc or 49'052 per cent. oxide of zinc; atomic weight 205Z09. 0.4225 gave 0'0715 water and 0'334 carbonic acid which gives the formula C12 H5 0" + 4 2 0.This salt however is then essentially altered part of its malic acid being converted into fumaric acid as will be shown in the sequel. L Acrn MALATE OF COPPEE. M Cu 0H20 + 2 aq -M Cu 0 H20 (100' C.). Prepared by dissolving hydrated oxide of copper in malic acid and evaporating at a temperature of 30' to 40' C. as a sinall blue crystalline body. 0*690of this salt gave 0.149 oxide or 21.521 per cent. of oxide of copper; atomic weight 2302*17. The composition calculated from this is as follows :-Calculated. I Found. 1 atom Malic acid . . . . 1461'39 63.69 1 ... Oxide ofcopper 3 atoms Water . . . . . 495'70 337*44 21.60 14.71 21'821 2294.53 Dried at 100' it loses 2 atoms of water and its atomic weight becomes 2069.57.~ MALATE OF SILVER.M 2 Ag 0. 0*2877salt gave 0-1777 silver or 66.339 per cent. of'oxide of' silver. Hence Chtwt.Soc. Mem VOL I F Dr. Eobert Hagen or&Malic Acid. Calculated. Found. 1 eq. Malic acid. . . 1461039 33.48 33-66 2 ... Oxide of silver 29W21 66.52 66.33 4361060 MALATE OF BARYTES.M 2 Ba 0 + 2 aq -M 2 BaO (~oo'C.). A solution of malic acid is ssturated with barytes water and evaporated at a very moderate temperature. The salt found crystallizes At 30' C. it loses one atom of water; at 100' C. it becomes quite anhydrous. Of the salt 0'5575 dried at the ordinary temperature gave 0*452 sulphate of baryta or 53'207 per cent. of barytes; which makes the atomic weight 3956*8 the calculated one being 3600.10.The salt dried by 30' C. gave 54'426 per cent. barytes. That dried at 100' C. is composed of 1 atom of malic acid and 2 atonis of barytes. L MALATE M 2 St 0 + 3 acj OF STRONTIAN. -M 2 St 0 f 2 aq (10o"C.). FUMARATE OF ZTHYL. OF OXIDE This ether is formed whenever malic acid is brought into contact with muriatic ether. Malic acid also when long mixed with absolute alcohol or with strong fuming hydro- chloric acid is converted into fumaric acid. This combination or fumaric Ether is heavier than water and has a grateful odour like that of fruit. It is slightly soluble in water and is therefore better separated from mu- riatic ether when mixed with the latter by distillation than by means of water.By potash fumaric aether is converted into alcoho1 and the fumarate of potash. Kept long in con- tact with ammonia it is converted into f'umaramide. Purified by being distilled over chloride of calcium 0.3515 ether gave 0*268 water and 0.669 carbonic acid. Hence Calculated. Found. 8 atoms Carbon . . 61 1'48 56*29 55'803 6 4 ... ... Hydrogen Oxygen.. 74%7 400*00 6.89 36'82 6.97 37-22 1086% C4H 02,N H2. FUMARAMIDE. This amide is obtained when funiarie ether is left a long time in contact with an excess of caustic ammonia. Its forma-tion is quite analogous to that ofoxarriideand the other coin- Dr. Robert Bagen OH Mutic Acid. pounds of amide. In cold water and absolute alcohol it is quite insoluble. It is soluble in boiling water and again precipitates as the water cools.Left long in contact with water it is completely converted into. fumarate of ammonia. Ammonia is disengaged by the fixed alkalies and a fumarate formed. By distillation it is decomposed into ammonia; a white body probably maleinic acid and a residue of charcoal are left. 0.426 of funiaramide gave 0'1335 water and 0'2780 car-bonic acid. By a qualitative determination of the nitrogen the latter was found to be to the carbonic acid in volume as 1 to 4. Carbon . . . . 42.37 Hydrogen . . . 5.53 Nitrogen . . . 24-53 Oxygen . . . . 27-77 100-00 This gives-Calculated. 4 atoms Carbon . . . . 305'74 42.46 s ... Hydrogen . . . 37'11.4 5.19 1 ... Nitrogen . . . 197-04 24*59 2 ... Oxygen .. . . 200*00 27-76 720-22 1OO*OO MALATES AT HIGHTEMPERATURES. If malates of the earths or alkalies are kept for some time at a temperature varying eorn 250' to 300' C. they are changed into fumarates water being the only other product. The changes produced are best observed in the following manner. The f'umarate produced is dissolved in as small a quantity of boiling water as possible and a small excess of nitric acid is added to it. The fumaric acid crystallizes fi-om the solution in its peculiar form possessing all the properties ascribed to it by Pelouze. I have prepared its silver salt to identify it with certainty. 0.2726 acid gave 0*0585water and 0.4115 carbonic acid. This gives the following formula for its coni- position :-Calculated.Found. 4 atoms Carbon. . -305*74 91-84 91-73 ct 4 ... ... Hydrogen 24*95 Oxygen . . 400*00 3'4 1 54.75 3.60 54.683 730.69 0'373.5 of the silver salt gave 0*320.5chloride of silver or F2 Dr. Ure on Pyroz-ylic Spirit. 69-422 oxide of silver; and 0.4270 gave W029 water and 0.224 carbonic acid. 4 atoms Carbon . . . 305.74 Calculated. 14.77 Found 14-50 3 atoms Oxygen . . . . 300*00 1 atom Hydrogen . . . 12-48 14.49 0'60 15.31 0.75 1 atom Oxide of silver 1451*6 70.14 69.42 2069-82 This remarkable change of malic acid saits into those of faniaric acid appears to me to bear a strong anabgy to the formation of the pyro-and metsphosphates but this is as yet not sufficiently proved by experiment. 1 have kept a satu-rated solution of fumaric acid at a boiling temperature for several days without the slightest change in it.And I have also kept a like solutim in a tube hermetically sealed for a considerable time at it temperature of 250° under a pressure therefore of nearly 15 atmospheres without its being altered in any of its properties. Hence fumaric acid does not appear to he reconvertible into malic acid.