Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
  • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D207/44—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members
  • C07D207/444—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members having two doubly-bound oxygen atoms directly attached in positions 2 and 5
  • C07D207/448—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members having two doubly-bound oxygen atoms directly attached in positions 2 and 5 with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to other ring carbon atoms, e.g. maleimide
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
  • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D207/44—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F22/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides or nitriles thereof
  • C08F22/36—Amides or imides
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
  • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
  • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
  • C23F11/14—Nitrogen-containing compounds
  • C23F11/145—Amides; N-substituted amides

Definitions

• the present invention relates to the preparation of N- substituted maleimides from the corresponding maleamic acids and/or mono-ammonium maleates.
• 654,847 describes the cyclization of the N-substituted maleamic acids in the presence of dehydrating agents, such as meta-, ortho-, pyroor polyphosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid and organic sulfonic acids, preferably with the use of an inert organic diluent which is advantageously immiscible with water and has a boiling range of from 80 to 180 C.
• dehydrating agents such as meta-, ortho-, pyroor polyphosphoric acid, phosphonic acid, phosphorous acid, phosphinic acid and organic sulfonic acids
• N-substituted maleimides can be obtained from N-substituted maleamic acids and/or the mono-ammonium salts of N-substituted maleic acids, in a simple manner in good yields, by heating the starting material in the presence of superheated steam, to a temperature within the range of from about to 400 C., and separating the corresponding N-substituted maleimide from the hot reaction mixture by the injection of water.
• the thermal treatment of the maleamic acid or ammonium maleate can be carried out either Without the addition of accessory agents or in the presence of dehydrating agents having an acid reaction.
• the maleamic acid from maleic anhydride and amine in known manner, and to isolate and dry the maleamic acid.
• the maleamic acid so obtained is then converted into the N-substituted maleimide by heating in the presence of superheated steam to a temperature preferably within the range of from about 200 to 250 C. and obtaining the N-substituted maleimide from the hot reaction mixture in a highly pure state by the injection of water.
• the mono-ammonium salts of the maleic acids are obtained in a very simple manner by placing the maleic anhydride and the amine to be introduced in an aqueous solution.
• This solution can be subjected to dehydration without isolating the mono-ammonium salt. It is, of course, also possible to isolate the mono-ammonium salt and to use it in the solid or molten state for the dehydration.
• the monoammonium salt of maleic acid is metered into the reaction vessel and heated in the presence of superheated steam, to a temperature preferably within the range of from to 250 C., and the formed maleimide is sep arated from the hot reaction mixture by the injection of water.
• the stream of steam passed into the reaction vessel continuously entrains the maleimide that has formed.
• the accruing minor amounts of impurities are removed by the water introduced through a nozzle.
• the maleimides so obtained are already in a purity above 99%, so that they can be used without further purification for polymerization reactions.
• dehydrating agents that may be used if desired are organic sulfonic acids, sulfuric acid, 0rtho-, diand polyphosphoric acids as well as the acid salts of polybasic acids, acid anhydrides, chlorides of zinc, magnesium and aluminum. These agents are added in an amount within the range of from 1 to 50 percent, preferably 5 to 20 percent, calculated on the maleamic acid applied, or the mono-ammonium salt.
• An essential advantage of the process of the present invention is that it can optionally be carried out continuously or discontinuously.
• the solution of mono-ammonium maleate is separately prepared, or the maleamic acid to be applied is separately melted in a container, in each instance either with or without dehydrating agents, and the melt or the solution is metered into a reaction vessel by means of a pump.
• mixtures or the maleamic acid itself are charged without pretreatment, in a pulverulent form, to the reactor by means of a screw conveyor.
• the yields attained by the process of the present invention amount to 50 percent to 90 percent of the theoretical yield, thus exceeding the yields of the prior art processes in most cases. This was an especially surprising observation when working in the presence of steam; in this case it was to be expected that owing to the steam the equilibrium of the reaction which proceeds with dehydration would be shifted, especially in the presence of large amounts of steam, quite considerably towards the starting materials.
• N-substituted maleimides obtained by the process of the present invention have a wide range of application for known industrial uses without further pretreatment or after-treatments. They may be used, for example, as monomers or 'comonomers for polymerization reactions. Moreover, they may be applied as fungicides, insecticides or f'ungistatic agents, as anti-oxidants, vulcanizers and rust preventives.
• EXAMPLE 1 In the course of one hour, 1000 grams of molten N-cyclohexyl maleamic acid were slowly metered, in the liquid state, by means of a pump into a round-bottomed flask heated at 230 C., while simultaneously passing through superheated steam (5000 grams per hour). Into the hot reaction gases pre-cooled to approximately 150 C., water was introduced through a nozzle for condensing the steam, whereon N-cyclohexyl maleimide was obtained in a nonacid and finely crystalline form (melting point: 87 to 90 C.).
• EXAMPLE 2 In a series-connected apparatus, a mixture of maleic anhydride was reacted with cyclohexyl amine to give N- cyclohexyl maleamic acid. 85 kg. of this reaction product were mixed, per hour, with 15 kg. of ortho-phosphoric acid of 85 percent strength and passed, with the admixture of 200 kg. per hour of superheated steam, through a tubular reactor at a temperature ranging from 220 to 240 C. Via an indirect cooling apparatus in which the reaction mixture was cooled to approximately 120 C., the reaction mixture travelled to another cooling chamher in which the steam was condensed by introducing water by means of a nozzle. The corresponding N-cyclohexyl maleimide simultaneously separated out in a pulverulent form so that, after filtration from the aqueous condensate, it could be used without additional purification for the copolymerization with vinyl chloride.
• EXAMPLE 3 200 grams of para-toluene sulfonic acid were added to 800 grams of N-phenyl maleic amide and treated, as described in Example 1, at a temperature of 280 C. in the presence of eight times the amount of superheated steam. A yellow N-phenyl maleimide of a melting point of 89 C. was obtained in a yield of 82 percent of the theoretical.
• EXAMPLE 4 750 grams of N(9,10-ethylene-9,10-dihydr0-1l-anthrylmethyD-maleamic acid were mixed with 250 grams of potassium hydrogen sulfate and charged in the solid state by means of a screw conveyor to the apparatus described in Example 1. At a temperature of 250 C., approximately 2000 grams of steam were passed in during the course of one hour.
• EXAMPLE 5 16 kg. of an aqueous solution of monocyclohexylammonium maleate of 62% strength, which contains 15% by weight of phosphoric acid (calculated on the amine salt), were metered in the course of one hour, while simultaneously passing in 20 kg. of steam having a temperature of 230 C., into the reaction vessel which was maintained at a temperature of 180 to 200 C. Water was introduced through a nozzle into the hot reaction gases, which had been pre-cooled to 150 C., for condensing the steam whereupon N-cyclohexyl maleimide was obtained free from acid in a pulverulent form in a yield amounting to 87% of the theoretical amount by weight. The product could be used without further afterpurification for copolymerizations.
• EXAMPLE 6 1000 grams of an aqueous solution of mono-tert.butylammonium maleate of 62% strength were metered into a cyclization vessel and treated as described in Example 5. Yield of N-tert.buty1 maleimide: 47% of the theoretical amount.
• EXAMPLE 7 90 parts of monoethyl-ammonium maleate were dissolved in 60 parts of water, 10 parts of concentrated H SO were added thereto, and the whole was treated in the manner as described in Example 5. N-ethyl maleimide was obtained in a yield amounting to 60% of the theoretical amount.
• EXAMPLE 8 200 grams of para-toluene sulfonic acid were stirred into 1400 grams of an aqueous solution of mono-phenylammonium maleate, and the solution was treated in the manner as described in Example 5. The N-phenyl maleimide was obtained in the form of yellow crystals in a yield amounting to 75% of the theoretical yield.
• EXAMPLE 9 750 grams of mono-N-(9,10-dihydro-9,IO-ethano-anthryl-(l1)-methyl)ammonium maleate were mixed with 250 grams of potassium hydrogen sulfate, the mixture was charged in the solid state to the reaction vessel by means of a screw conveyor and treated in the manner described in Example 5. N-(9',10-dihydro-9,IO-ethanoanthryl-(11)-methy1)-maleimide was obtained in a yield of 47 of the theoretical amount.
• N-substituted maleimides from a correspondingly N-substituted starting material selected from the group consisting of maleamic acids and monoammonium salts of maleic acids, wherein the formed N-substituted maleimide is separated from the hot reaction mixture by the injection of water, the improvement which comprises heating the said starting material in the presence of superheated steam to a temperature within the range of from C. to 400 C.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Pyrrole Compounds (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Cited By (5)

• 1967
  • 1967-09-09 DE DE1670923A patent/DE1670923C3/de not_active Expired
• 1968
  • 1968-09-04 NL NL6812562A patent/NL6812562A/xx unknown
  • 1968-09-06 AT AT868968A patent/AT285562B/de not_active IP Right Cessation
  • 1968-09-09 BE BE720560D patent/BE720560A/xx unknown
  • 1968-09-09 FR FR165512A patent/FR95593E/fr not_active Expired
  • 1968-09-09 GB GB42805/68A patent/GB1187167A/en not_active Expired
• 1971
  • 1971-03-22 US US00126990A patent/US3758498A/en not_active Expired - Lifetime

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