Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
  • C07D201/02—Preparation of lactams
  • C07D201/04—Preparation of lactams from or via oximes by Beckmann rearrangement
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
  • B01J23/42—Platinum
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B21/00—Nitrogen; Compounds thereof
  • C01B21/082—Compounds containing nitrogen and non-metals and optionally metals
  • C01B21/14—Hydroxylamine; Salts thereof
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C249/00—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton
  • C07C249/04—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton of oximes
  • C07C249/08—Preparation of compounds containing nitrogen atoms doubly-bound to a carbon skeleton of oximes by reaction of hydroxylamines with carbonyl compounds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C251/00—Compounds containing nitrogen atoms doubly-bound to a carbon skeleton
  • C07C251/32—Oximes
  • C07C251/34—Oximes with oxygen atoms of oxyimino groups bound to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals
  • C07C251/44—Oximes with oxygen atoms of oxyimino groups bound to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals with the carbon atom of at least one of the oxyimino groups being part of a ring other than a six-membered aromatic ring
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
  • C07C51/41—Preparation of salts of carboxylic acids
  • C07C51/412—Preparation of salts of carboxylic acids by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2601/00—Systems containing only non-condensed rings
  • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
  • C07C2601/14—The ring being saturated
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• the present invention relates to a process for the preparation of cyclohexanone oxime by reacting cyclohexanone with a hydroxylammonium salt.
• the invention further relates to a process for the production of caprolactam.
• DE-C 14 93 198 describes, according to claim, the preparation of cyclohexanone oxime by reacting cyclohexanone with an aqueous solution of a hydroxylamine salt of an inorganic or organic acid, wherein a residual solution containing aqueous acid obtained after the removal of the oxy is obtained Performs salt / acid separation, uses the separated amount of acid to prepare the hydroxylamine salt starting solution.
• a disadvantage of this process is the great expenditure on equipment and the use of sulfuric acid and ammonia in the workup of the acid / salt mixture when a carboxylic acid, in particular acetic acid, is used, so that ammonium sulfate or a phosphate - in smaller amounts than previously - but still has to be disposed of.
• EP-A 620 042 describes the preparation of hydroxylammonium salts by reduction of nitrogen monoxide with hydrogen in the presence of a hydrogenation catalyst in strong mineral acids or aliphatic Ci-Cs monocarboxylic acids such as formic and acetic acid, the hydrogenation catalyst being obtainable by treatment a platinum metal salt with finely divided sulfur and subsequent reduction of the platinum metal salt to metallic platinum metal.
• a hydrogenation catalyst in strong mineral acids or aliphatic Ci-Cs monocarboxylic acids such as formic and acetic acid
• cyclohexanone oxime is prepared by reacting cyclohexanone with hydroxylammonium formate in aqueous formic acid.
• the molar ratio of hydroxylammonium formate to cyclohexanone is usually chosen in the range from 1.3: 1 to 1: 1, preferably from 1.2: 1 to 1: 1.
• the hydroxylammonium formate is converted into aqueous formic acid, the concentration increasing
• Hydroxylammonium formate is generally selected in the range from 10 to 16, preferably from 12 to 14,% by weight.
• concentration on hydroxylammonium formate is generally selected in the range from 10 to 16, preferably from 12 to 14,% by weight.
• Formic acid in the aqueous formic acid solution is in the aqueous formic acid solution
• the temperature is generally chosen in the range from 70 to 90, preferably from 75 to 80 ° C.
• the pressure is generally selected in the range from 90 to 120, preferably from 100 to 120, particularly preferably from 105 to 110 kPa.
• the pH is usually selected in the range from 0.5 to 2.5, preferably from 1.2 to 1.8.
• the pH value is generally set by the buffering action of the ammonium formate / formic acid system itself, if one uses, preferably, hydroxylammonium formate solutions which come directly from the hydroxylammonium formate synthesis without further work-up.
• the reaction can be carried out batchwise or continuously, in one or more stages, preferably in two stages, particularly preferably continuously and in two stages.
• the residence time is usually 1.5 to 3 hours per stage.
• the yields are generally in the range from 94 to 98, based on the cyclohexanone used.
• hydroxylammonium formate is used, which is obtained by reducing nitrogen monoxide with hydrogen in the presence of a hydrogenation catalyst in aqueous formic acid.
• the preparation of hydroxylammonium formate is usually carried out by suspending the hydrogenation catalyst in aqueous formic acid and introducing a mixture of nitrogen monoxide and hydrogen into the suspension.
• the formic acid content is generally chosen in the range from 20 50 to 500, preferably from 100 to 250 g of formic acid per liter of formic acid / water mixture. According to previous observations, hydrogenation at concentrations of more than 60% by weight of formic acid is no longer possible.
• the hydrogenation of nitrogen monoxide is generally carried out at a temperature in the range from 30 to 80, preferably from 35 to 60 ° C. Furthermore, the pressure during the hydrogenation is usually chosen in the range from 100 to 3000, preferably from 150 to 2000 kPa.
• the ratio of formic acid to catalyst is usually chosen in the range from 10 to 100, preferably from 30 to 80, g of platinum-graphite catalyst per liter of the aqueous formic acid.
• catalyst is treated
• the usual hydrogenation catalysts known for the preparation of hydroxylammonium salts can be used as the catalyst.
• a hydrogenation catalyst is particularly preferred, produced by the process described in DE-A 4,311,420. According to this process, platinum is treated with finely divided sulfur and then the platinum thus treated is reduced to metallic platinum.
• Suitable platinum salts are, in particular, the water-soluble salts such as the halides, nitrates and sulfates. Examples include:
• Platinum (IV) compounds such as hexachloroplatinic acid and its alkali metal and ammonium salts, tetrachloroplatinate or tetrachlorodihydroxyplatinic acid; and
• Platinum (II) compounds such as tetrachloroplatinic acid and its alkali metal salts or plati (II) chloride;
• mixtures of essentially salts with other metal salts for example arsenic, antimony, selenium or tellurium salts, can also be used.
• finely divided sulfur for example the commercially available "sulfur bloom" is used as the sulfur used for partial poisoning. It is preferred to use sulfur with a particle size of less than 500 ⁇ m, preferably less than 50 ⁇ m, particularly preferably one
• Suitable sulfur is commercially available, for example, as "Kumulus WG®” network sulfur (BASF) or using methods known per se, in particular sieves, from, for example, sulfur bloom or finely ground sulfur.
• the platinum salt is treated with the finely divided sulfur in aqueous solution by bringing the aqueous platinum salt solution into contact with the finely divided sulfur.
• the sulfur can also be used as a colloidal sulfur solution.
• the sulfur is preferably added in the form of an aqueous suspension.
• Suitable surfactants which are also referred to as dispersants, can be found, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 4th edition, volume 23, Verlag Chemie, Weinheim, 1983, pp. 31-39. Examples include:
• Polyacrylates polyvinyl sulfonates, polyvinyl pyrrolidone, TAMOL ® (BASF), Schaeffer salt and lignin sulfonates.
• the surfactant used is lignin sulfonates (known, for example, from Ulimann, Encyclopedia of Industrial Chemistry, 4th edition, vol. 16, pp. 253 ff., Verlag Chemie, 1978), preferably alkali metal lignosulfonates such as sodium and potassium lignin sulfonate , since they can be easily removed with the washing water when washing the finished catalyst and because of their easy degradability they do not represent an environmental burden.
• lignin sulfonates known, for example, from Ulimann, Encyclopedia of Industrial Chemistry, 4th edition, vol. 16, pp. 253 ff., Verlag Chemie, 1978
• alkali metal lignosulfonates such as sodium and potassium lignin sulfonate
• the surfactants are generally added to the reaction mixture before the sulfur is added to the platinum salt or advantageously to the aqueous sulfur suspension.
• the weight ratio of surfactant to sulfur is generally chosen in the range from 0.1 to 50, preferably from 1 to 15,% by weight.
• the temperature during the treatment of the platinum salt with the finely divided sulfur is usually chosen in the range from 20 to 95 ° C., preferably from 40 to 95 ° C., particularly preferably from 50 to 85 ° C.
• the pH during the treatment of the platinum salt with the finely divided sulfur is generally chosen in the range from 1.5 to 11.5, preferably from 2.5 to 8.5, particularly preferably 4.5 to 8.5 , very particularly preferably from 7.0 to 7.5.
• the duration of treatment of the platinum salt with the finely divided sulfur i.e. the period from the addition of the finely divided sulfur to the addition of the reducing agent is generally chosen in the range from 0.5 to 60 min, preferably from 2 to 15 min.
• the molar ratio of platinum to sulfur is generally selected in the range from 90 to 10, preferably from 75 to 35, mol%.
• the platinum salt is reduced to metallic platinum by expediently adding a reducing agent to the reaction mixture obtained after treating the platinum salt with finely divided sulfur.
• Suitable reducing agents are usually all known reducing agents for platinum salts to platinum, e.g. Hydrazine, formaldehyde, formic acid or an alkali metal or alkaline earth metal formate such as. Sodium, potassium and calcium formate, particularly preferably formic acid.
• the molar ratio of platinum to reducing agent is generally chosen in the range from 0.5 to 100, preferably from 5 to 85 mol%.
• the temperature during the reduction is usually chosen in the range from 20 to 95 ° C., preferably from 40 to 95 ° C., particularly preferably from 50 to 85 ° C.
• the pH during the reduction essentially depends on the amount and type of reducing agent.
• the pH is generally selected in the range from 0.5 to 3.5, preferably from 1.0 to 2.5.
• the catalyst is generally worked up in the customary manner, for example by filtering it off from the reaction mixture and washing it appropriately with water.
• the reduction and, if desired, the treatment with finely divided sulfur is carried out in the presence of a catalyst support such as graphite or activated carbon, preferably graphite.
• a catalyst support such as graphite or activated carbon, preferably graphite.
• the platinum salt is particularly preferably mixed with finely divided graphite before the treatment with finely divided sulfur, generally with a particle size in the range from 0.1 to 1000, preferably from 0.1 to 300 ⁇ m, particularly preferably from 5 to 100 ⁇ m.
• the molar ratio of carbon (or graphite or activated carbon) to platinum is generally chosen in the range from 99.99 to 10 mol%, preferably 99.99 to 30 mol%, especially if it is platinum, preferably 99, 99 to 90 mol%, particularly preferably from 99.98 to 95.0 mol%.
• the formic acid used and released in the preparation of cyclohexanone oxime is separated from the reaction mixture obtained.
• the separated formic acid can then be used again in the production of hydroxylammonium formate and cyclohexanone oxime.
• step (c) separating the formic acid ester obtained in step (b) from mixture B by distillation,
• step (d) the formic acid ester obtained from step (c) is saponified in a manner known per se to obtain a mixture C comprising essentially formic acid and the corresponding alcohol used in step (a),
• the formic acid from stage (d) is separated from the mixture and used to prepare hydroxylammonium formate and / or cyclohexanone oxime.
• the cyclohexanone oxime is usually obtained by phase separation processes, for example in a phase separator at 70 to 75 ° C. in the upper phase, from the reaction mixture obtained in the preparation of the cyclohexanone oxime.
• a mixture A is obtained which essentially consists of water, formic acid and, if appropriate, impurities such as ammonium formate and traces of hydroxylammonium formate.
• this mixture A is mixed with a C 1 -C 4 -alkanol such as methanol, ethanol, n-, i-propanol, n-, i-, sec.- and tert.
• a C 1 -C 4 -alkanol such as methanol, ethanol, n-, i-propanol, n-, i-, sec.- and tert.
• Butanol the alkanol usually being used in an excess of 10 to 40, preferably 20 to 40,% by weight, based on the formic acid.
• Formic acid is particularly preferably esterified with methanol, since methyl formate can be easily separated off because of its low boiling point (31.8 ° C. at 100 kPa).
• the esterification is carried out according to methods known per se, for example by heating the mixture A to which the alkanol has been added to a temperature in the range from 40 to 80 ° C. and by maintaining a pressure in the range from 150 to 500 kPa. Esterification produces a mixture B containing the formic acid ester.
• the formic acid ester is removed by distillation from mixture B. In a preferred embodiment, the formic acid ester formed is removed continuously during the esterification.
• esterification is carried out acid-catalyzed by using up to 2% by weight, based on formic acid, of an acid, preferably a mineral acid such as sulfuric acid, hydrochloric acid or phosphoric acid.
• an acid preferably a mineral acid such as sulfuric acid, hydrochloric acid or phosphoric acid.
• This procedure is preferably carried out in a stirred tank reactor with a distillation column attached, the C 1 -C 4 -alkyl formate formed being continuously separated off by distillation.
• the pH is usually in the range of 0.5 to 2.5.
• the formic acid ester, C 1 -C 4 -alkyl formate is usually saponified in a manner known per se, ie cleaved into formic acid and C 4 -C 4 -alkanol.
• the saponification can be carried out in an acidic as well as in a basic environment.
• the saponification can be carried out in a stirred tank, with either acid or base catalysis being carried out in a manner known per se.
• the saponification can be carried out in a fixed bed reactor which contains a basic ion exchanger.
• the reactors used preferably contain a rectification attachment in order to separate the system H 2 ⁇ / HCOOH / C ⁇ -C 4 alkanol / formic acid ester.
• the formic acid is separated off from the reaction mixture by customary methods, for example by distilling off the lower-boiling constituents of the reaction mixture.
• the separated formic acid preferably in the form of an aqueous solution, is preferably used for the synthesis of hydro- xylammonium formate and / or for the synthesis of cyclohexanone oxime, so that formic acid is circulated.
• methanol is used in the esterification and is obtained in the saponification
• methyl formate which has a very low boiling point, can be distilled off overhead, methanol removed as a side stream, while the aqueous formic acid remains in the bottom and can preferably be recycled for the synthesis of hydroxylamine.
• This process has the advantage that the recovered formic acid is free of by-products, especially of other organic impurities ("TOC" total organic carbon). Since the by-products are removed, the accumulation of undesired by-products is avoided in a circular manner.
• TOC organic impurities
• caprolactam is prepared by Beckmann rearrangement of cyclohexanone oxime in the presence of a C ⁇ -C 4 -carboxylic acid such as formic acid, acetic acid, propionic acid or butyric acid, preferably formic acid and acetic acid, particularly preferably formic acid.
• a C ⁇ -C 4 -carboxylic acid such as formic acid, acetic acid, propionic acid or butyric acid, preferably formic acid and acetic acid, particularly preferably formic acid.
• the molar ratio of cyclohexanone oxime to carboxylic acid is preferably selected in the range from 1: 1 to 1:30, preferably from 1: 1 to 1:10.
• the cyclohexanone oxime is usually used as a C 4 -C 4 carboxylic acid solution, the concentration of the generally aqueous carboxylic acid solution generally being in the range from 10 to 70% by weight, preferably from 15 to 50% by weight.
• the same carboxylic acid which is used as the solvent for the rearrangement is particularly preferably used, formic acid being particularly preferred.
• the temperature is generally chosen in the range from 50 to 150, preferably from 70 to 120 ° C.
• the pressure is generally selected in the range from 100 to 1000, preferably from 100 to 200 kPa.
• the pH value is freely established; the use of buffers is usually not necessary.
• the rearrangement can otherwise be carried out according to methods known per se, ie optionally continuously or discontinuously, in one or more stages, preferably in multiple stages.
• the residence time is generally 2 to 10, preferably 3 to 6 hours.
• cyclohexanone oxime which has been prepared by one of the processes according to the invention described above and is documented in the subclaims.
• the C 1 -C 4 -carboxylic acid used at the beginning of the rearrangement is distilled off from the reaction mixture, and it is preferably used again for the rearrangement of the cyclohexanone oxime.
• the caprolactam produced according to the invention can be worked up by methods known per se, such as extraction of the crude lactam with a solvent, for example by the processes described in the following documents: EP-B 22,261, DE-A 37 35 054, US 28 13 858, EP-B 411 455.
• the caprolactam produced according to the invention serves as a starting material for the production of polycaprolactam and corresponding copolymers.
• the process according to the invention for the preparation of cyclohexanone oxime has the advantage that it works without the accumulation of salt. Furthermore, the carboxylic acids used can be circulated. A further advantage lies in the rearrangement of the oxime with a carboxylic acid, since the disposal of ammonium sulfate, as in the usual processes of the prior art, is also avoided.
• 50 g of the catalyst thus treated were 25 wt. In 1250 ml. -% formic acid suspended and treated with H 2 at 40 ° C (so-called "activation").
• the total amount of exhaust gas was 99.8 l.
• Cyclohexanone and hydroxylamine were mixed in a 2 liter stirred tank reactor. Hydroxylamine was added as a hydroxylammonium formate solution.
• the reaction was carried out by first adding excess NH 2 OH (20 mol%) to the cyclohexanone in order to implement it completely. After the cyclohexanone oxime formed had been separated off (as the upper phase in a phase separator), the lower phase (with the unreacted NH 2 OH) was fed back into the stirred tank reactor together with fresh hydroxylammonium formate solution.

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• 1995
  • 1995-06-02 DE DE19520271A patent/DE19520271A1/de not_active Withdrawn
• 1996
  • 1996-05-24 WO PCT/EP1996/002240 patent/WO1996038407A1/de not_active Ceased
  • 1996-05-24 PL PL96323676A patent/PL323676A1/xx unknown
  • 1996-05-24 JP JP8536165A patent/JPH11506440A/ja active Pending
  • 1996-05-24 BR BR9608960A patent/BR9608960A/pt not_active Application Discontinuation
  • 1996-05-24 CZ CZ973591A patent/CZ359197A3/cs unknown
  • 1996-05-24 CN CN96194378A patent/CN1186484A/zh active Pending
  • 1996-05-24 EP EP96917419A patent/EP0828707A1/de not_active Withdrawn
  • 1996-05-24 KR KR1019970708654A patent/KR19990022175A/ko not_active Withdrawn
  • 1996-05-24 AU AU60001/96A patent/AU6000196A/en not_active Abandoned
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