IL26039A - Production of isatoic anhydride and certain halo derivatives thereof - Google Patents

Description

Production of isatoic anhydride and certain halo derivatives thereof DONALD WILLIAM 24805 nd or o It is a further of the Invention to provide a controlled method for reacting a compound having the formula where and can be or a tive therewith to produce a salt of the a metal and an acid to in high a substance having the formula where and have the indicated In the attached 1 a plot of maximum time after mixing phthallmide or a halo derivative water and an and before addition of a halite to the mixture versus temperature thereof In producing an acid anhydride according to the and 2 is a plot showing per cent hydrolysis of sodium phthallmide to sodium phthalamate as a function of and at different According to the a compound having the formula Z wherein and represent or and a stantially equivalent proportion of a reactive therewith to produce a salt of the compound are mixed with a quantity at a temperature not higher than about which quantity is at least cient to essentially dissolve the Not more than X minutes after the mixing of the the material and the a quantity per mole of the an oxide or hydroxide of magnesium or or a carbonate of or any of which as well as metallic equivalent to equivalents of a metal is added to the resulting X being a function of the temperature of the mixture of the the material and the and being represented by one of the curves of 1 of the attached the exothermic heat of reaction between the salt of the compound and the hypohallte has per gram of the to gram the solution adjusted to and maintained at a pH of from to assuming that the total heat when the reaction is carried out is the of the reaction mixture times the temperature rifle thereo in degrees this pH adjustment made at an Intermediate point in the when substantially all of the phthalimide or lent reacted at least as far as a particular but before more than about 20 per cent thereo has reacted as far as the sodium salt of anhydride or the adjustment is to a pH om 6 to most to one from to The following specific trates the best presently modes for practicing the instant provides a basis an explanation of the of the limitations set forth in the preceding Example 1 A one liter beaker charged with of a water solution containing grams of sodium a or or any of which is and at a of The solution the beaker was stirred by a agitator during the rapid addition of grams of and throughout the remaining steps in the temperature of the reaction mixture was held at for minutes after completion of the charging of the a 300 portion of sodium at was then added When exothermic reaction had generated 6600 gram as indicated b the reaction mixture reaching a temperature of a total of of N furic acid was added thereto as required to bring the pH thereof and to maintain it The first sulfuric acid addition was made approximately 20 seconds after the sodium hypochlorite was charged and the adjustment required several Crude anhydride was then by of the washed with and dried for hours in an oven at The total recovery amounted to or per cent of The material was light tan in color and assayed per The procedure described has also been fied by varying the time interval between the addition of phthalimlde to the sodium hydroxide solution and the addition of the sodium hypochlorite while otherwise completely reproducing the It has been found that the yield of isatolc anhydride depends upon the length of this he sodium hypochlorite solution was prepared by reacting grams of chlorine with grams of sodium hydroxide in sufficient water to produce 300 of solution at prepared from distilled water at a pH of from to sodium and The solution held at a fixed temperature for a definite time and is then poured into a solution containing one equivalent of acid per equivalent of sodium hydroxide used in the phthallmlde The resulting mixture is then titrated with standard caustic to a pH of from to The number of of sodium hydroxide required for the back titration equals the number of moles of phthallmlde and the phthallmlde remaining unhydrolyzed a precipitate which can be separated and determined Such tests have been carried on the basis of these has been determined that the hydrolysis of sodium phthallmlde to sodium phthalamate and that the rate at such hydrolysis occurs is a direct function of It has also been determined that the extent to such hydrolysis proceeds prior to the addition of sodium hypochlorite solution thereto governs the per cent yield of the crude isatoic anhydride produced by the procedures summarized in Table within the limits with respect to proportions of reactants which are feasible for use in the production of isatoic anhydride by the method of temperature is the principal factor which governs the rate at which sodium phthallmlde is hydrolyzed to sodium For a solution of sodium phthallmlde can stand for mately minutes at before 10 per cent of the sodium phthalimide hydrolyzed sodium but 10 per cent is hydrolyzed to sodium phthalamate in approximately 2 minutes at The results of these tests are summarized graphically for solution temperatures of and by the curves of 2 which are plots of mole per cent of sodium phthalamate versus time for the indicated By careful Investigation it has been determined for the production of in high by reactions of the type not more than 50 per cent of the sodium phthalimide should be hydrolyzed to sodium phthalamate before sodium hypochlorite or its lent is added thereto to the reactions by which the desired anhydride is ultimately Curve A of the plot of 1 of the attached drawings represents the as a function of required for 50 per cent of the sodium phthalimide in such a solution to hydrolyze to In accordance with the sodium hypochlorite its equivalent is added to such a solution not more than X minutes after addition of phthalimide to a sodium hydroxide solution where X is a function of the temperature of the and is represented by Curve A of the X not greater than the time represented by Curve B of the whioh is similar to Curve but shows the relationships for 30 per cent most X not greater than the time represented by Curve C of the drawin which shows the ships for 20 per cent If either heating or codling is used before the hypochlorite a mean time X not longer than should be Preventing hydrolysis of sodium phthalimide by adding sodium hypochlorite quickly to the reaction mix duced from phthalimide and sodium hydroxide does not necessarily assure a good yield of This point has been demonstrated by still another series of tests which the procedure described in Example was except that the sulfuric acid was added to the action products a a different either earlier or Data concerning this series of tests summarized in Table Table II Heat of Reaction fore Addition Per Cent Yield Isatoic Anhydride Reaction product not isatoic anhydride of reaction in times temperature rise in degrees mineral acid was added in this pH was lowered by an acid formed in the reaction It be appreciated that the procedure which has been described above Is adlabatlo in provided that Incidental heat transfer between the reaction mixture and the surroundings in an adlabatlo the final reaotlon temperature Is a direct function of the amount of heat evolved by an exothermic Is the production of lsatolc anhydride or the in accordance the certain conclusions can be drawn from the data presented in Table or a salt an intermediate product in a series of reactions which commences when sodium hypochlorite is added to a solution f sodium Adding furic acid to the reaction to control pH as cated the procedure of Example causes the series of reactions to so that lsatolc anhydride can be recovered in a hig By correlating the conditions employed the reactions with the time at which sulfuric or an equivalent added to the reaction an optimum yield of anhydride can be Carefully controlled tests have been carried out to demonstrate that a pH adjustment of the reaction mixture with sulfuric acid or an equivalent commenced when exothermic heat of reaction between sodium hypochlorite and the water solution of sodium phthalimide and sodium phthalamate controlled in accordance with the data shown has per gram mole of phthalimide from to Preferably the acid is added to the reaction mixture when the exothermic heat of It has ascertained that when a made as discussed above only a not than about 20 per of the or equivalent has reacted as far as the sodium of isatoic anhydride or the adjustment is not to stop the but to control the part of the the pH adjustment should be only after substantially all of the phthalimide or equivalent has been reacted at least as far as phthalamic and should to a sufficiently high to maintain therein both the salt and the disodium salt of suf low to convert substantially of the sodium salt of isatoic anhydride in the reaction mixture to isatoic It will be appreciated that an of a reaction to a of about the cedure described above in requires several and that a reaction which releases 6600 gram calories in about twenty and by the reaction of proximately portions of is ceeding at an extremely rapid It has been ascertained that the reaction can be controlled more readily by adding about per cent of the acid theoretically required to neutralise the hydroxide or equivalent in the action and by making such addition slightly later in the and substantially For substantially the or slightly results can be achieved if the procedure of 1 is except that 75 cent of the sulfuric acid theoretically required to neutralise the hydroxide in the reaction mixture is added thirty seconds after the hypochlorite further adjustments are made as required to maintain a pH of approximately The experimental procedure has been carried out to demonstrate the by which isatoic anhydride or an equivalent therefor is produced according to the method of the Example 2 The procedure described in 1 was except thirty seconds after the sodium hypochlorite a cc portion of sulfuric acid was added substantially instantaneously to the reaction followed immediately by about 300 grans of chopped The beaker was then surrounded with chopped and the reaction vigorously to effect rapid cooling to A small quantity of a white cipitate was observed in the reaction and was subsequently identified as isatoic This cipitate was separated from the mother liquor by dried and The recovery amounted to about 4 or slightly less tha 10 per cent of Care during filtration of the isatoic anhydride to prevent warming of the mother the liquor was allowed to to a temperature in the range of 15 to and periodic additions of sulfuric acid were as to maintain a pH of about During a period of a few a further precipitate This which was subsequently identified as isatoic was separated by and combined with the first The bined isatoic anhydride fractions were then and found to amount to or 93 per cent of The procedure described in the preceding paragraph has also been repeated except after filtration of the first isatoic anhydride fraction the mother liquor was acidified to a pH of about A substantial precipitate and was identified as acid after and A portion of the phthalamic acid was subsequently mixed with and the water was adjusted and at a pH of approximately at about The acid and white isatoic anhydride then It will be apparent from Example as has been previously the pH adjustment which is made according to the process of the instant invention is for the purpose of controlling the major part of a molecular which ultimately produces isatoic anhydride rather than for the purpose of stopping It has been determined from appropriate titration curves that both the and salts of acid in at below the minimum at which sodium isatoic anhydride Since isatoic anhydride itself is substantially insoluble in the pH adjustment according to the made as previously causes neutralization of the sodium isatoic anhydride which had formed prior to the pH as well as precipitation of the isatoic anhydride and maintaining the pH within such range as reaction proceeds causes precipitation of subsequently formed isatoic This precipitation effectively prevents undesired side reactions which occur if the pH adjustment is not or if the pH is not maintained within the operable range subsequent to the It has also been determined that the disodium salt of acid will undergo molecular to form the sodium salt of isatoic anhydride but that the salt of acid will not undergo such the effectiveness of the instant method depends upon the previously unknown facts that the sodium salt of isatoic anhydride does not exist at within the previously indicated that the and salts of acid do exist within such that the disodium salt of acid will molecular rearrangement to the sodium salt of isatoic at within such and in undergoing such each molecule of the disodium salt of phthalamic acid releases a sodium cation which converts a molecule of the monosodium salt of acid to the disodium salt The production of isatoic anhydride the in accordance with the has heretofore been cussed reference to an essentially adiabatic Such a reaction is preferred some particularly because the course thereof can be folloxved by simple temperature so that control is comparatively the reaction mixture can be either or if throughout all or any portion as has been strated the extent to which sodium phthalimide or the like is hydrolyzed to sodium phthalamate or the like should be minimized in order to obtain an optimum yield of acid and since elevated tures favor such there is ordinarily no reason to supply heat to the solution from phthalimid a halogenated sodium hydroxide or an equivalent and In a compara low temperature is so that any heat transfer is preferably from the but high temperatures can be after addition of sodium hypochlorite or an comparatively low temperatures would be expected to favor the progression of the exothermic and any heat transfer is preferably from the reaction but comparatively high temperatures can be and heat can actually be supplied to the reaction provided that the reactions are stopped at the proper s indicated The following example the production of a chloro isatolc anhydride from the corresponding chloro Example 3 A 200 milliliter beaker charged with 79 of water at a temperature of and of sodium The water in the beaker was stirred by a agitator during the rapid addition of a portion of monochloro phthalimide and throughout the remaining steps in the The temperature of the reaction mixture held at for minutes after completion of the charging of the chloro phthalimide portion of the sodium chlorite solution described in Example 1 then added When gram calories were released as indicated by the reaction reaching a of a 40 portion of hydrochloric acid was added as required to bring the thereof and maintain it at and crude chloro isatoic anhydride 0 H was recovered by filtration of the slurry which The crude anhydride was washed with water and dried for 15 hours in an oven at The recovery amounted to or 102 per cent of The material was light tan in and had a melting with of and was indicated by infra red absorption to be The procedure described in Example can be substituting equivalent amounts of a carbonate of or a hydroxide of or or an oxide of or or Ha or Ca for the tuting equivalent of a hypochlorite of Mg or Ca or of a hypobromite of or Ca for the sodium In all results substantially equivalent with those of the example can be It is that any reactive with phthalimlde or a halo derivative thereof to proauce a salt can be used in place of sodium and that any metal preferably any can be used in place of the sodium chlorite in producing an acid anhydride according to the A substantially equivalent proportion of the material which is reactive with phthalimlde or a halo phthalimlde should be used to produce the salt from equivalent thereof to equivalents per mole of the or chlo o from equivalent to equivalents of the metal should be used per mole of or its The function of the sulfuric acid in the foregoing procedures is merely to reduce the pH of the reaction whereby high yields of isatoic anhydride or its equivalent are The chemical Identity of the acid is in no way using any desired provided that the pH is adjusted to and maintained within of Alkali metal most desirably sodium alkali metal most desirably sodium hypochloritej and sulfuric as used in the procedure of Example are preferred reactants because of their ready availability and comparatively low Isatoic anhydride or any of certain halo rivatives as defined can be produced in accordance with the invention by either continuous or batchwise As will be apparent to one skilled in the various changes and modifications can be made from the specific procedures set above without parting the spirit and scope of the attached using any desired provided that the pH is adjusted to and maintained within range of Alkali metal most desirably sodium alkali metal most desirably sodium and sulfuric as used in the procedure of Example are preferred reactants because of their ready availability and comparatively low Isatoic anhydride or any of certain halo rivatives as defined can be produced in accordance with the by either continuous or batchwise As will be apparent to one skilled the various changes and modifications can be made from the specific procedures set above without parting the spirit and scope of the attached insufficientOCRQuality

Claims (1)

1. 21 A method for producing am acid anhydride hich comprises mixing a compound having the wherein each of the symbols and represents a hydrogen or halogen atom and a substantially equivalent proportion a material reactive therewith to produce a salt of the compound with a quantity of water at leas sufficient to dissolve the per mole of the and at time when at least 50 per cent of the salt in an unhydrolized condition and not been converted to the corresponding equivalent to equivalents of a metal hypohalite to the resulting and the solution and taining it at a between and sufficiently low convert substantially all of the salt of the anhydride therein to free anhydride but sufficiently high to maintain therein both the the of an having the in which is a halogen when substantially all of the compound in the reaction mixture has been reacted at least as 22 far as the hut more than about per cent thereof has been reacted as far as the anhydride A according 1 said compound is for the production of isatoic a A method according to Claim 1 or 2 wherein said material is sodium hydroxide and said metal hypohalite is sodium method according to Claim 2 or wherein the temperature of mixture of the the material and the is not higher than preferably not higher than A method according to any preceding modified i that the addition of hypohalite ie made at time when at least 70 per cent of the salt remains in an insufficientOCRQuality