WO2014202031A1 - 一种联产己二酸和硝基环己烷的方法 - Google Patents

一种联产己二酸和硝基环己烷的方法 Download PDF

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WO2014202031A1
WO2014202031A1 PCT/CN2014/081818 CN2014081818W WO2014202031A1 WO 2014202031 A1 WO2014202031 A1 WO 2014202031A1 CN 2014081818 W CN2014081818 W CN 2014081818W WO 2014202031 A1 WO2014202031 A1 WO 2014202031A1
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cyclohexane
reaction
adipic acid
nitrocyclohexane
catalyst
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PCT/CN2014/081818
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English (en)
French (fr)
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WO2014202031A8 (zh
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罗和安
游奎一
蹇建
周忠仓
刘平乐
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湘潭大学
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Priority to EP14813695.5A priority Critical patent/EP3012243A1/en
Publication of WO2014202031A1 publication Critical patent/WO2014202031A1/zh
Publication of WO2014202031A8 publication Critical patent/WO2014202031A8/zh

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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C201/00Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
    • C07C201/06Preparation of nitro compounds
    • C07C201/08Preparation of nitro compounds by substitution of hydrogen atoms by nitro groups
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/16Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
    • C07C51/31Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation of cyclic compounds with ring-splitting
    • C07C51/316Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation of cyclic compounds with ring-splitting with oxides of nitrogen or nitrogen-containing mineral acids
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2601/00Systems containing only non-condensed rings
    • C07C2601/12Systems containing only non-condensed rings with a six-membered ring
    • C07C2601/14The ring being saturated

Definitions

  • the present invention relates to a process for the one-step conversion from cyclohexane to produce adipic acid and nitrocyclohexane with high selectivity.
  • Adipic acid commonly known as fatty acid, is a white solid at room temperature, molecular formula (CH 2 ) 4 (C00H) 2 , molecular weight 146. 1430, normal melting point 152 ° C.
  • Adipic acid is a very important industrial material and intermediate used in the manufacture of nylon 66, plasticizers, greases, insecticides and adhesives.
  • the synthesis route of adipic acid mainly includes cyclohexane oxidation two-step method, cyclohexene hydration-oxidation two-step method, cyclohexane (molecular oxygen) oxidation one-step method, butadiene carbonylation method, cyclohexene hydrogen peroxide One-step oxidation method and biological oxidation method.
  • Nitrocyclohexane is a colorless oily liquid at room temperature, molecular formula C 6 H u N0 2 , molecular weight 129. 1571, boiling point 205. 5 ° C, insoluble in water, soluble in organic solvents such as ethanol, ether, chloroform, benzene, etc. , is an important organic solvent and intermediates (for example, hydrogenation to obtain cyclohexylamine), but the current use is far less extensive than adipic acid. If the method of partial hydrogenation to cyclohexanone oxime can be industrialized, the market demand can be greatly increased.
  • KA oil (mainly containing a mixture of cyclohexanone and cyclohexanol) is prepared by air oxidation of cyclohexane, and then KA The oil is used as a raw material to obtain adipic acid by oxidation with nitric acid.
  • the single pass conversion and KA oil yield in the cyclohexane oxidation process are very low, generally 3%-5% and 82%-83%, respectively; and the single pass conversion and adipic acid yield of the nitric acid oxidized KA oil process are also Not high, generally 5%-12% and 90%-94%, respectively, and the amount of nitric acid is large, each ton of product consumes 68% of nitric acid 1. 3 tons, and produces a large amount of waste acid, wastewater and C0, N0 X , N 2 0 and other toxic gases.
  • cyclohexene hydration-oxidation two-step process is a new method of industrialization in recent years. It first hydrates cyclohexene to cyclohexanol, and then oxidizes cyclohexanol with nitric acid to obtain adipic acid.
  • the advantage of this method is that the selectivity of the first step reaction is high, but the second step still has problems of high energy consumption and large environmental impact.
  • cyclohexene is obtained by selective hydrogenation of benzene, and its reaction and separation. The conditions are harsh and the energy consumption is high.
  • One-step synthesis of adipic acid by oxidation of cyclohexene hydrogen peroxide is an environmentally friendly process. It uses hydrogen peroxide as an oxidant to catalyze the oxidation of cyclohexene to adipic acid in a one-step process under catalytic conditions.
  • This method requires relatively expensive catalysts, such as methyltrioctyl ammonium chloride, sodium tungstate-oxalic acid system or sodium tungstate-sulfuric acid system, and the reaction and separation conditions for the preparation of cyclohexene are more stringent and the production cost is higher. High, and high hydrogen peroxide consumption, which affects the industrialization process of cyclohexene oxidation in one step.
  • the biooxidation method encodes an enzyme in a gene cluster isolated from an aerobic denitrification strain to obtain a synthetase for converting cyclohexanol to adipic acid, which can give cyclohexanol under suitable growth conditions. Converted to adipic acid.
  • this process is expensive and is not yet suitable for large-scale industrial production.
  • US 4263453 (1981) proposes to increase the amount of acetic acid solvent (the molar ratio of cyclohexane to acetic acid is 1:6) and introduce a small amount of methyl ethyl ketone and water to increase the conversion of cyclohexane and adipic acid.
  • Selectivity US 5,321,157 (1994) suggests the use of oxygen-enriched air to reduce the amount of acetic acid solvent (the molar ratio of cyclohexane to acetic acid is close to 1:1) and to obtain higher adipic acid selectivity.
  • US0147777A1 (2004) proposed the use of octanoic acid as a solvent, cobalt acetylacetonate as a catalyst, and an imide group-containing compound as a cocatalyst to synthesize cyclohexanol/ketone and adipic acid by air oxidation of cyclohexane; US7507856B2 (2009) proposed 4 And the selectivity of the adipic acid and the adipic acid selectivity of the adipic acid can be up to 7. 17%, respectively, and the cyclohexane ketone is used as a catalyst.
  • the traditional mixed acid nitration method is mainly used, that is, the nitration reaction of cyclohexane with nitrate-sulfur mixed acid or nitric acid-acetic anhydride as a nitrating agent.
  • the selectivity of the method is poor, and there are various side reactions such as oxidation, hydrolysis, hydroxylation, etc., so the post-treatment process is complicated, and a large amount of waste acid and wastewater containing organic compounds are generated, the treatment cost is high, the environmental pollution problem is serious, and the clean production is The requirements are far apart.
  • N0 X nitrogen oxide
  • x > 1 a nitrating agent to directly synthesize a gas phase nitration alkane
  • the main by-products are the corresponding alcohols, aldehydes, ketones, acids or nitrates and nitrites, as well as the deep oxidation by-products C0 2 and 3 ⁇ 40.
  • Canadian Patent CA710356 (A) and US Patent US 3255262 (A) reported a method for the gas phase nitration of cyclohexane to synthesize nitrocyclohexane: mainly for the purpose of increasing the yield of nitrocyclohexane, the reaction temperature is 220-375 ° C, and the residence time is 20-150. second.
  • the main problem with these methods is that a large amount of deep oxidation by-products C0 2 and 0 are easily formed, and the yield based on cyclohexane is low.
  • CN101781217A (2010) proposed a method for co-production of nitrocyclohexane and adipic acid by gas phase uncatalyzed or gas-solid catalytic nitration oxidation reaction using N0 2 and cyclohexane, with the aim of nitrocyclohexane and hexamethylene.
  • the yield of the two products is maximized, but the main product is nitrocyclohexane, which has less adipic acid (selectivity is generally less than 22%), and also avoids more advanced oxidation by-products C0 2 and C0. . Hoot and Kobe (Ind. Eng.
  • the reaction temperature is 50 ° C
  • the reaction time is more than 40 hours
  • the adipic acid selectivity is about 76%
  • the nitrocyclohexane selectivity is about 3%
  • the total selectivity is about 79%
  • the reaction temperature is At 80 ° C
  • the reaction time is shortened to 3 hours
  • the selectivity of adipic acid drops to about 40%
  • the selectivity of nitrocyclohexane rises to about 7%
  • the total selectivity of the two is about 47%
  • the reaction temperature is 90
  • the reaction time was shortened to about 50 minutes, but the adipic acid selectivity was almost zero and the nitrocyclohexane selectivity was about 22%.
  • the present invention is directed to a method for producing adipic acid and nitrocyclohexane with high selectivity by one-step conversion of cyclohexane with N0 X ( 1 ⁇ X ⁇ 3, the same below) as a nitrating oxidizing agent.
  • N0 X 1 ⁇ X ⁇ 3, the same below
  • Reducing energy consumption and production costs is a new way to achieve green synthesis of adipic acid and nitrocyclohexane.
  • the process of the invention is more suitable for continuous production.
  • N0 X is both a nitrating agent and an oxidizing agent
  • N0 X and cyclohexane can be nitrated to form nitrocyclohexane, and cyclohexane can also be oxidized to adipic acid.
  • the reaction formula is as follows:
  • the method of the present invention uses nitrogen oxides N0 X as an oxidizing agent and a nitrating agent, and converts cyclohexane into one step by using reaction conditions such as reaction temperature, reaction pressure, reactant ratio, and catalyst or inducer.
  • reaction conditions such as reaction temperature, reaction pressure, reactant ratio, and catalyst or inducer.
  • the selective and adjustable ratio of adipic acid and nitrocyclohexane are combined, and the NO produced by the reaction is recycled to a certain amount of 0 2 to form an NO ring.
  • the main function of the catalyst or inducer is to increase the cyclohexane conversion and the N0 l" rate, and to assist in adjusting the ratio of the product adipic acid to nitrocyclohexane.
  • a process for the high-selective co-production of adipic acid and nitrocyclohexane from a one-step conversion of cyclohexane characterized by: N0 X ( 1 ⁇ X ⁇ 3,
  • N0 X 1 ⁇ X ⁇ 3
  • the regulation of the formation ratio of cyclohexane, adipic acid selectivity can be adjusted between 5% and 95%.
  • the method is carried out in a production apparatus comprising a cyclohexane conversion system, a NO oxidation system, a phase separation system, a light phase material separation system, and a heavy phase material separation system, wherein the oxidation and nitration reactions are in the ring
  • the oxidation of NO formed by the reaction is carried out in an NO oxidation system, and the reaction mixture obtained after the oxidation and the nitrification is separated in a phase separation system to obtain a light phase material and a heavy phase material.
  • cyclohexane and NO X are oxidized in a liquid phase or a gas phase state. Nitrification reaction.
  • the conversion reaction temperature of the cyclohexane conversion system is from 0 to 150 ° C, preferably from 5 to 100 ° C;
  • the reaction pressure of the conversion system is from normal pressure to 10 MPa, preferably from atmospheric pressure to 3 MPa; and the reactants are cyclohexane and N0.
  • the molar ratio of X is 0.1 to 20, preferably 0.
  • N0 X is 1 NOx of X ⁇ 3, such as N0 2 , N 2 0 4 , N 2 0 3 , N 2 0 5 , etc. Or a mixture thereof, preferably 1. 5 ⁇ x ⁇ 3.
  • the reaction product from the cyclohexane conversion system can be separated into a light phase material and a heavy phase material by a phase separation system; the light phase material is mainly unconverted cyclohexane and dissolved.
  • the nitrocyclohexane is obtained by separating the unconverted cyclohexane by a light phase material separation system to obtain a crude nitrocyclohexane, and the separated cyclohexane is recycled;
  • the heavy phase material is mainly Adipic acid crystals, a solid catalyst and a small amount of acidic aqueous phase formed by the reaction can be obtained by a heavy phase material separation system to obtain a crude adipic acid.
  • the gaseous product N0 from the cyclohexane conversion system is converted to N0 X (1 ⁇ X) via a NO oxidation system.
  • the cyclohexane conversion reaction may be added with a catalyst or an inducing agent for the purpose of increasing the conversion of cyclohexane and the total selectivity, and assisting in adjusting the ratio of the product adipic acid and nitrocyclohexane;
  • the mass ratio of the mass ratio to the cyclohexane is 0-0. 1 when the liquid catalyst or the inducer is used.
  • the types of catalysts or inducers are vanadium phosphorus oxide complexes, imide compounds, molecular sieves, solid acids, metal oxides, organic or inorganic acid salts, Salen transition metal catalysts, heteropolyacids. Classes, peroxides and alcohols, ketones, aldehydes, esters, etc.; light phase materials from phase separation systems can also be used as inducers.
  • the solid catalyst is separated from the heavy phase material separation system and can be recycled directly or indirectly to the cyclohexane conversion system.
  • the method of the present invention is a method for simultaneously producing adipic acid and nitrocyclohexane from a cyclohexane by a liquid phase or a gas phase reaction by using a nitrogen oxide N0 X as an oxidizing agent and a nitrating agent.
  • the reaction conditions such as reaction temperature, reaction pressure, reactant ratio and catalyst or inducer are used as control means to produce adipic acid and nitrocyclohexane in a highly selective and adjustable ratio, and the NO produced by the reaction is recovered. After a certain amount of 0 2 is generated, N0 X is recycled.
  • the main function of the catalyst or inducer is to increase the cyclohexane conversion and the N0 l" utilization rate, and to assist in adjusting the ratio of the product adipic acid to nitrocyclohexane.
  • a process for co-production (or production) of adipic acid and nitrocyclohexane from cyclohexane comprising the steps of:
  • the above method further comprises:
  • phase separation the reaction mixture obtained in the step (a) is subjected to phase separation (for example, by standing, sedimentation or centrifugation) to be separated into light and heavy two phases, wherein the light phase includes nitrocyclohexane, unreacted The cyclohexane and optional inducer, the heavy phase comprises the aqueous acid phase formed by the reaction, the adipic acid crystals and the optional catalyst.
  • the upper light phase is also referred to as the oil phase
  • the lower heavy phase is also referred to as the aqueous phase.
  • the above method further comprises:
  • step (c) secondary separation: (cl) separating unreacted cyclohexane and optionally an inducer from the light phase obtained in step (b) to obtain a crude nitrocyclohexane containing a small amount of by-product, and / or (c2) separating the crude adipic acid crystals and the optional catalyst from the heavy phase obtained in the step (b), and the remaining aqueous acid phase is post-treated to recover the nitric acid and a small amount of acidic by-products therein.
  • the above method further comprises:
  • the reactor is either stored in a vessel for use in the next batch of reactions).
  • the light phase obtained in (b) contains an inducing agent and a small amount of a by-product such as an alcohol, a ketone or an ester which induces, and a small amount of the light phase is directly used as an inducer for recycling.
  • the catalyst isolated in (c) is used directly or indirectly (i.e., after purification or regeneration).
  • the reactor used in step (a) of the present application is generally a closed reactor, preferably a non-tubular reactor, more preferably an autoclave reactor or a high pressure reactor.
  • the reactor described above is a closed reactor (non-tubular reactor) such as an autoclave reactor or a high pressure reactor, or two or three or four or five or six or seven One or eight or more closed reactors in series such as an autoclave reactor or an autoclave.
  • the reactor used in step (a) is a closed reactor, such as a tubular reactor.
  • the reactor described above is preferably made of stainless steel.
  • the reactor described herein is preferably a tubular reactor or a tower reactor, and may be a one-pot reactor or a multi-tank reactor or the like.
  • mixing is carried out in a reactor as described above using a mixing device such as a stirring paddle or a stirring bar, for example for a non-tubular reactor using a dynamic mixing device such as a stirring paddle or a stir bar or for a tubular reactor Use static mixing equipment or static mixers.
  • a mixing device such as a stirring paddle or a stirring bar
  • a dynamic mixing device such as a stirring paddle or a stir bar or for a tubular reactor
  • static mixing equipment or static mixers are examples of static mixers.
  • the method of the present invention can be carried out in a batch manner.
  • the reactor used in step (a) is two or three or four or five or six or seven or eight or more reactors in series (such as a autoclave reactor or a high pressure reactor)
  • the process of the invention can be carried out in a semi-continuous manner or in a continuous manner.
  • the reaction temperature of the step (a) is 0-150 ° C, preferably 5-140 ° C, preferably 10-130 ° C, preferably 20-120 ° C, preferably 30-110 ° C, Preferably 40_10 (TC, preferably 45-90 ° C or 40-95 ° C, preferably 50-80 ° C or 60-85 ° C, further preferably 55-75 ° C or 65-82 ° C, still more preferably 58-70 ° C Or 70_80 ° C.
  • the molar ratio of cyclohexane to NOx in the step (a) is 0.1 to 20:1, preferably 0. 15- 15 :1, preferably 0. 2- 10 : 1 0. 40-1 :1 ⁇ -0. 95 : 1, more preferably 0. 45-0. 75 : 1, more preferred
  • N0 X is 1. 5 ⁇ x ⁇ 3 oxynitride, preferably N0 2 , N 2 0 4 , N 2 0 3 , N 2 0 5 or any two, three or A mixture of four.
  • the mass ratio of the catalyst to the cyclohexane is 0-0. 30: 1, preferably 0. 005-0. 27: 1, preferably 0. 01-0. 25: 1, preferably 0 05 ⁇ 0. 23 : 1, Preferably 0. 08- 0. 22 : 1, preferably 0. 10- 0. 20 : 1, and / or the mass ratio of the inducer to cyclohexane is 0-0. 25 : 01 ⁇ 0. 12:1 ⁇ Preferably 0. 003-0. 20: 1, preferably 0. 005-0. 20: 1, preferably 0. 008- 0. 15: 1, preferably 0. 01- 0. 12: 1, preferably 0. 02 0: 10: 1 ⁇ Preferably, 0. 03- 0. 10: 1.
  • reaction in the step (a) is at 1 atm (i.e., 0. 10133 MPa) - 10 MPa, preferably 1. 12 atm - 5 MPa, preferably 1. 15 atm _ 4 MPa, more preferably 1 2MPa, 0. 9-1. 25MPa, 1. 09-1. 20MPa. 2MPa, 0. 9MPa, 0. 8-1. , E.g
  • the pressure is generally between 1 atmosphere to 1. 3MPa; When the reaction of the step (a) is carried out at a temperature of from 50 to 85 ° C, the pressure is generally between 1.5 and 1. 5 MPa; when the reaction of the step (a) is carried out at 60 to 80 ° C, the pressure Generally, it is between 0.6 and 1. 18 MPa (for example, 0.7 or 0.8 or 0.9 or 1.13 MPa); or when the reaction of the step (a) is carried out at 60 to 75 ° C, the pressure The pressure is generally between 1. 08 - 1 and the pressure is generally between 0. 6 - 1 and the pressure of the step (a) is usually in the range of 1. 08 - 1 Between 14 MPa (for example, 1.13 MPa).
  • reaction time (or residence time) of the step (a) is generally 0.5 to 30 hours, preferably 1 to 28 hours (for example, 15, 20, 24, 26 hours), preferably 1. 5-25 hours, preferably 2. 0-20 hours, preferably 2. 5-18 hours, such as 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 hours.
  • in the reactor with cyclohexane oxidation N0 X and nitration reaction in a liquid phase or gas-liquid state refers to mixing liquid N0 X and cyclohexane (
  • the liquid N0 X is dissolved in cyclohexane)
  • the oxidation and nitration reactions are carried out at an elevated temperature and with stirring or thorough mixing.
  • the reactor with cyclohexane oxidation N0 X and nitration reaction in a liquid phase or gas-liquid state refers to a liquid mixture of cyclohexane and N0 X (For example, dissolving liquid N0 X in cyclohexane), the oxidation and nitration reactions are carried out at elevated temperatures and with sufficient agitation of the agitation equipment or with thorough mixing by static mixing equipment.
  • the "in the gas-liquid phase” as used in the present invention means that there is a liquid reaction mixture in the reactor, and a gas phase (containing or mainly containing NO gas generated by the reaction) is present in the upper portion or above the liquid surface of the reaction mixture.
  • the N0 X in the liquid below 20 ° C preferably at a temperature below 15 ° C (e.g. below 5 ° C) was dissolved in cyclohexane to form a reaction mixture.
  • the resulting reaction mixture is reacted in a closed reactor at elevated temperatures (such as the reaction temperatures described above). More preferably, the reaction of step (a) is carried out with thorough mixing or stirring.
  • the step (a) described above is carried out by dissolving N0 X in a ring at a temperature below 20 ° C, preferably below 15 ° C, in the presence or absence of a catalyst or inducer.
  • a temperature below 20 ° C preferably below 15 ° C
  • a catalyst or inducer preferably, a catalyst or inducer.
  • the reactor at elevated temperature (such as the reaction temperature described above) (preferably, under elevated pressure, and / or under mixing or stirring) in the liquid phase or gas phase
  • the oxidation and nitration reactions are carried out to obtain a reaction mixture containing adipic acid and nitrocyclohexane, wherein N0 X is any one or a mixture of two or more of nitrogen oxides satisfying 1 ⁇ X ⁇ 3 .
  • the present inventors have discovered that many materials can catalyze or induce, and different catalysts or inducers can modulate the ratio of adipic acid to nitrocyclohexane.
  • the catalyst is one or a mixture of two or more selected from the group consisting of vanadium phosphorus oxide complexes such as M-VP0 or M-A1VP0 (wherein M is a transition metal) , such as Mn, Cu, Co, Ni or Cr); imide compounds such as N-hydroxyphthalimide, NN' dihydroxy pyromellitic acid imide or N-hydroxy-1, 8-naphthalimide (they are preferably used in combination with 9,10-, 1-aminoindole or 2-aminoindole as an auxiliary for imide-based compounds); transition metals such as Mn , Cu, Co, Ni or Cr) acetylacetone complex catalyst; zeolite or molecule Sieves such as HZSM-5 molecular sieve, HY molecular sieve, ⁇ -zeolite, TS-1 titanium silica molecular sieve or MA1P0-5 molecular sieve (wherein ruthenium is Fe, Mn, Mg, Co or
  • the catalyst is a vanadium phosphorus oxide complex such as M-VP0 or M-A1VP0 (wherein M is a transition metal such as Mn, Cu, Co, Ni or Cr).
  • M is a transition metal such as Mn, Cu, Co, Ni or Cr.
  • N0 X (for example, at a lower temperature such as lower than 20 ° C, preferably lower than 15 ° C or lower than 5 ° C) is dissolved in cyclohexane before or at the beginning of the reaction.
  • the liquid reaction mixture is then reacted in the closed reactor at elevated temperature in the form of a liquid mixture, especially during the reaction or at the same time as the reaction is thoroughly mixed or stirred.
  • the inventors unexpectedly found that adipic acid was obtained with very high conversion and selectivity.
  • the single pass conversion of cyclohexane can reach 20-60%, preferably 30-50%, and the total selectivity of the main products adipic acid and nitrocyclohexane can reach 98% (or 99%) -99.9% or even 100%.
  • the ratio of the two is adjustable, the selectivity of adipic acid is generally in the range of 60-90% or 63-85%, for example, 70%, 80% or 85% or more than 90% (the selectivity is based on cyclohexyl) Alkane).
  • the purity of adipic acid can reach 98% by weight or more.
  • the pressure or pressure in this application refers to the absolute pressure (unit: atmospheric pressure or MPa).
  • the process of the invention can be carried out in a batch, semi-continuous or continuous manner.
  • Figure 1 depicts a batch process, but it can also be a continuous process which is more suitable for continuous production.
  • the method of the invention mainly comprises a cyclohexane conversion system (Rl), a NO oxidation system (R2), a phase separation system (S1), a light phase material separation system (S2) and a heavy phase material separation system (S3), etc. Part of the composition.
  • (II) Oxidation and nitration of cyclohexane (1) and N0 X (2) in a cyclohexane conversion system (R1), mainly producing adipic acid and nitrocyclohexane.
  • the conversion system reaction temperature is 0-150 ° C, preferably the temperature is 5-100 ° C;
  • the conversion system reaction pressure is atmospheric pressure -10 MPa, the preferred pressure is atmospheric pressure -3 MPa ;
  • cyclohexane (1) and N0 X ( 2) the molar ratio is 0. 1-20, the preferred molar ratio is 0.
  • the reaction system when using a solid catalyst, the reaction system is liquid-solid two-phase or gas-liquid solid three-phase, the quality of the solid catalyst and cyclohexane The ratio is 0-0. 1; when the liquid catalyst or the inducer is used, the reaction system is liquid phase or gas-liquid two phase, the mass ratio of the liquid catalyst or the inducer to cyclohexane is 0-0. 1; 3) is a newly added catalyst or inducer.
  • the reaction product from the cyclohexane conversion system (R1) can be divided into light phase materials by the phase separation system (S1) (5) And heavy phase material (8).
  • the light phase material (5) is mainly unconverted cyclohexane and the reaction product nitrocyclohexane dissolved therein;
  • the heavy phase material (8) is mainly the reaction product adipic acid crystal, solid catalyst, and acidity formed by the reaction. water box.
  • the main function of the catalyst or inducer is to increase the cyclohexane conversion and total selectivity, and to assist in adjusting the ratio of the product adipic acid and nitrocyclohexane, so that the catalyst is added or not added as needed.
  • Agent The present inventors have found that many substances can catalyze or induce such a substance, mainly of the following: or a mixture thereof:
  • Vanadium phosphorus oxide complex (VP0 or A1VP0) and its modified catalyst, such as M-VP0 or M-A1VP0, wherein M is a transition metal oxide such as Mn, Cu, Co, Ni, Cr; N-hydroxyphthalic acid Imide, NN' dihydroxy pyromellitic acid diimide, N-hydroxy-1, 8-naphthalimide and other imide compounds, the auxiliary agent is 9, 10- ⁇ , Terpenoids such as 1-aminopurine and 2-aminopurine; complex catalysts of acetylacetone complex transition metals (Mn, Cu, Co, Ni, Cr, etc.); molecular sieves such as HZSM-5, HY molecular sieve, ⁇ -zeolite, titanium-silicon molecular sieve TS-1 and supported metal-phosphorus molecular sieve MA1P0-5 ( ⁇ is an oxide of Fe, Mn, Mg, Co, Cu, etc.); solid acid catalysts such as sulfonic acid resin, sulfuric acid/sili
  • heteropolyacid catalysts such as HPAs and phosphotungstic acid; and the like; peroxides such as benzoyl peroxide, hydrogen peroxide, t-butyl hydroperoxide, etc.; ketones such as cyclohexanone, butanone, acetone, etc.; Alcohols such as cyclohexanol, pentanol, butanol, propanol, ethanol, methanol, etc.; aldehydes such as butyraldehyde, propionaldehyde, acetaldehyde, etc.; esters such as ethyl acetate, n-butyl acetate, and nitric acid Ester and so on.
  • peroxides such as benzoyl peroxide, hydrogen peroxide, t-butyl hydroperoxide, etc.
  • ketones such as cyclohexanone, butanone, acetone, etc.
  • Alcohols such as cyclohe
  • the conversion system described in the above process may be a tubular reactor, a tower reactor or the like, or may be a one-pot reactor or a multi-tank reactor or the like.
  • the single pass conversion of cyclohexane can reach 20-70%, and the total selectivity of the main products adipic acid and nitrocyclohexane (based on cyclohexane) can reach more than 95%, Adjustable ratio, selectivity to adipic acid (based on cyclohexane) Can reach more than 85%.
  • the one-step conversion of cyclohexane to the adipic acid and nitrocyclohexane method of the present invention can not only greatly simplify the production process and equipment, More importantly, the conversion rate of cyclohexane and the selectivity of adipic acid and nitrocyclohexane can be greatly improved, and waste generation and environmental pollution can be greatly reduced from the source, while saving resources and reducing energy consumption. And reduce production costs.
  • a high value of adipic acid is unexpectedly obtained with high selectivity in a relatively simple manner.
  • Figure 1 is a process for the selective and selective production of adipic acid and nitrocyclohexane by cyclohexylation and oxidation.
  • BEST MODE FOR CARRYING OUT THE INVENTION The following examples are intended to illustrate the invention, but not to limit the invention. Described in the embodiment is a batch process, but the process of its continuation is also not limited, and the method is more suitable for continuous production.
  • Example 1 Press cyclohexane N0 2 molar ratio of 0.2: 1, the ratio by mass of cyclohexane and catalyst 1: 0.1, 5. 04 g cyclohexanone was added in a 0.2 L autoclave Alkane, 13.80 g of liquid N0 2 and 0.54 g of catalyst Cr_AlVP0; reacted at 80 ° C and 2.0 MPa and stirred for 24 h.
  • the layers After standing and cooling, the layers are separated, the upper layer is an oil phase, mainly containing unreacted cyclohexane and the product nitrocyclohexane, and the lower layer is mainly a mixture of adipic acid crystals, catalyst solids, and reaction water, etc.;
  • the filter cake is washed with a quantitative amount of cyclohexane and distilled water respectively; the collected filtrate and the washing liquid are separated to obtain an oil phase and an aqueous phase, respectively, and the oil phase is quantitatively determined by gas chromatography internal standard method.
  • the composition was determined by aqueous phase liquid chromatography external standard method; the filter cake was dissolved in quantitative methanol, the catalyst solid was filtered, and the filtrate was quantitatively analyzed by liquid chromatography external standard method. 3% ⁇ The selectivity of the cyclohexane is 60.3%, the selectivity of adipic acid is 84. 4%, the selectivity of nitrocyclohexane is 11.3%, the sum of the two is 95.7%.
  • Example 2 As Example 1, the reaction temperature was 100 ° C and the reaction pressure was 2. 9 MPa. The conversion of cyclohexane is 75.4%, the selectivity of adipic acid is 81.7%, the selectivity of nitrocyclohexane is 11.5%, and the sum of the two is 93. 2%.
  • Example 3 As in Example 1, a molar ratio of cyclohexane to NO 2 of 1:0 was added to 8.40 g of cyclohexane and 4.60 g of liquid N0 2 , the catalyst was VP0; and the reaction temperature was 60°. 6 MPa ⁇ C, the reaction pressure is 0. 6 MPa. 5% ⁇ The selectivity of the cyclohexane was 11.1%, adipic acid selectivity of 80. 6%, nitrocyclohexane selectivity 11.9%, the sum of the two options 92.5%.
  • Example 4 As in Example 1, the difference was that no catalyst was added. The conversion of cyclohexane was 18.6%, the selectivity of adipic acid was 63. 1%, the selectivity of nitrocyclohexane was 23. 2%, and the sum of the two was 86.3%.
  • Example 5 As in Example 1, except that the molar ratio of cyclohexane to NO 2 was 3:1, 19.6 g of cyclohexane and 3.58 g of liquid NO 2 were added without a catalyst. 2% ⁇ The selectivity of the selectivity of the hexane is 5.2%, the selectivity of the nitrocyclohexane is 32.0%, the sum of the two is 85.2%.
  • Example 6 As Example 1, except that different solid catalysts were used, and the corresponding cyclohexane conversion, adipic acid selectivity and nitrocyclohexane selectivity were obtained as follows: Order ring ⁇ selectivity /%
  • the reaction temperature is 0. 5% of the inducing agent cyclohexanone, the reaction temperature is 0. 9 79. 5 14. 0 93. 5
  • Example 7 9 MPa ⁇ The reaction pressure is 1. 9 MPa.
  • the conversion of cyclohexane was 55.3%, the selectivity of adipic acid was 81.7%, the selectivity of nitrocyclohexane was 12.6%, and the sum of the two was 94.3%.
  • Example 8 As in Example 1, except that a different, in 5. 0 L stainless steel autoclave, was added 553. 3 g liquid N0 2 202. 0 g of cyclohexane and 4. 0 g of the catalyst Ni-AlVP0. After standing and cooling, the gas phase component is sampled and analyzed, and then the gas material is metered by gas venting to about 429.3 g, which is mainly N0 2 (215. 3 g) NO (213. 7 g) and a trace amount of cyclohexane. and C0 2; after gas drained and all liquid and solid material measurement after liquid separation by suction filtration to give 133. 1 g and the filtrate cake was 193. 5 g; 98.
  • the filtrate is metered and sampled and analyzed, except for methanol, which mainly contains adipic acid (96. 3 wt%) and a small amount of succinic acid. And glutaric acid (3.5% by weight) and succinic anhydride and glutaric anhydride (0.2% by weight); the methanol solution was distilled under reduced pressure, washed with water, and dried to obtain a purity of 99.6%. Diacid product. 8% ⁇ Cyclohexane conversion rate of 61.66%, adipic acid selectivity 84.6%, nitrocyclohexane selectivity 10. 8%
  • Example 9 The liquid NO 2 was first dissolved in cold (less than 15 ° C) cyclohexane to form a homogeneous solution having a molar ratio of cyclohexane to NO 2 of 1:1. Then transferred to a stainless steel high pressure reactor, and then added a certain amount of catalyst Cr-AlVP0, cyclohexane and catalyst mass ratio of 1: 0; sealed, heated and stirred for oxidation reaction.
  • the reaction temperature is 60 ° C
  • the reaction pressure is 0.8 MPa (gauge pressure)
  • the reaction time is 24 h.
  • the reaction mixture is allowed to stand to cool to room temperature, and the gas phase containing N0 in the upper portion of the reactor is directly introduced into the oxidation reactor and oxidized with pure 02 to oxidize N0 to NOx (1 ⁇ X ⁇ 3);
  • the gas phase is collected and stored in a storage container until the gas in the storage container is passed into the oxidation reactor and oxidized with pure 02 to oxidize N0 until a sufficient amount of gas is collected after a plurality of batches of reaction.
  • NOx (1 ⁇ X ⁇ 3) reuse.
  • the nitrification product nitrocyclohexane is dissolved in the upper oil phase, and the lower layer is mainly adipic acid, a small amount of oxidation product and a catalyst.
  • Adipic acid is precipitated and precipitated in the form of crystals; the oil phase is quantitatively analyzed by gas chromatography internal standard method, and the lower layer is dissolved in an organic solvent to separate adipic acid, and the content of the liquid chromatography external standard is legal. 6% ⁇ The total selectivity of the two is 92.6. The total selectivity of the two is 92.6. The selectivity of the adipic acid is 11.9%, the selectivity of the nitrocyclohexane is 11.9%. % (selectivity is based on cyclohexane).

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Abstract

本发明涉及一种高选择性联产己二酸和硝基环己烷的方法。本发明采用氮氧化物NOx为氧化剂和硝化剂,将环己烷一步高选择性转化为己二酸和硝基环己烷,并通过调节反应物配比、反应温度和压强、催化剂或诱导剂的种类和用量等转化条件,来实现己二酸与硝基环己烷生成比例的调控;反应产生的NO可以回收再与氧发生反应转化为NOx循环利用。

Description

种联产己二酸和硝基环己垸的方法 技术领域
本发明涉及一种从环己烷一步转化, 高选择性联产己二酸和硝基环己烷的方法。 背景技术 己二酸(ADA)俗称肥酸, 常温下为白色固体, 分子式 (CH2) 4 (C00H) 2, 分子量 146. 1430, 正常熔点 152°C。 己二酸是一个非常重要的工业材料和中间体, 主要用于制造尼龙 66、 增塑 剂、 润滑脂、 杀虫剂和粘合剂等。 迄今为止己二酸的合成路线主要有环己烷氧化两步法、 环 己烯水合-氧化两步法、 环己烷(分子氧)氧化一步法、 丁二烯羰基化法、 环己烯双氧水氧化 一步法和生物氧化法等。
硝基环己烷常温下为无色油状液体, 分子式 C6HuN02, 分子量 129. 1571, 沸点 205. 5 °C, 不溶于水, 易溶于乙醇、 ***、 氯仿、 苯等有机溶剂, 是一种重要的有机溶剂和中间体 (例 如通过氢化制取环己胺) , 但目前用途远不如己二酸广泛。 如果部分氢化还原为环己酮肟的 方法能够工业化, 则市场需求可以大幅度增加。
目前工业生产己二酸一般都采用以环己烷为原料的两步氧化法: 首先通过空气氧化环己 烷制得 KA油 (主要含环己酮和环己醇的混合物) , 然后再以 KA油为原料通过硝酸氧化制得 己二酸。在环己烷氧化过程的单程转化率和 KA油收率都很低, 一般分别为 3%-5%和 82%-83%; 而硝酸氧化 KA油过程的单程转化率和己二酸收率也不高, 一般分别为 5%-12%和 90%-94%, 且 硝酸用量大, 每生产 1吨产品消耗 68%的硝酸 1. 3吨, 并产生大量的废酸、废水以及 C0、 N0X、 N20等有毒气体。 由此可见, 虽然环己烷两步氧化法工艺比较成熟并被工业生产普遍采用, 但 存在能耗高、 环境影响大、 资源利用率低、 生产成本高等问题。 环己烯水合-氧化两步法是近 些年工业化的一个新方法, 它首先将环己烯水合为环己醇, 再采用硝酸氧化环己醇得己二酸。 这个方法的优点是第一步反应的选择性高, 但第二步仍然还存在能耗高, 环境影响大等问题, 此外环己烯是从苯选择性部分加氢而获得, 其反应和分离条件都比较苛刻, 能耗较高。
环己烯双氧水氧化一步合成己二酸是一个环境友好的工艺方法, 它是以过氧化氢为氧化 剂, 在催化条件下催化氧化环己烯一步合成己二酸。 这个方法由于需要比较昂贵催化剂, 如 甲基三辛基氯化铵、 钨酸钠 -草酸体系或钨酸钠 -硫酸体系, 加上制取环己烯的反应和分离条 件比较苛刻、 生产成本较高, 以及双氧水消耗较高等原因, 从而影响了环己烯氧化一步合成 己二酸的工业化进程。生物氧化法是在好氧脱硝菌株中分离出来的一种基因簇对酶进行编码, 从而得到将环己醇转化为己二酸的合成酶, 该酶在合适的生长条件下可将环己醇转化为己二 酸。 但该过程费用昂贵, 目前尚不适合大规模工业化生产。
采用分子氧直接氧化环己烷一步合成己二酸一直是人们所期待的一种方法, 早在上世纪 40年代, US 2223493 ( 1940 ) 就提出了以乙酸作溶剂, 可溶性过渡金属盐 (钴、 铜、 锰等) 为催化剂, 采用空气氧化环己烷直接合成己二酸。 以此方法为基础, US 4263453 ( 1981 ) 提 出加大乙酸溶剂用量 (环己烷与乙酸的摩尔比为 1 : 6 ) 以及引入少量的丁酮和水, 可以提高 环己烷转化率和己二酸选择性; US 5321157 ( 1994) 则提出采用富氧空气, 可降低乙酸溶剂 的用量 (环己烷与乙酸的摩尔比接近 1 : 1 ) , 并可获得较高的己二酸选择性。 虽然这些方法 可以获得较高的环己烷转化率和己二酸选择性, 但是也存在较多的问题: 首先, 在其反应温 度和压力条件下, 乙酸对设备具有较大的腐蚀性; 其次, 目的产物己二酸和其它副产难以从 乙酸溶剂中分离和提纯; 第三, 可溶性催化剂很难从乙酸溶剂中分离出来, 尽管 FRA2722783 ( 1996 ) 和 FRA2746671 ( 1997 ) 提出过解决催化剂回收利用的方法, 但其过程复杂、 成本昂 贵。 因此, 以乙酸为溶剂的分子氧直接氧化环己烷制己二酸的方法很难工业化。
US0147777A1 ( 2004)提出以辛酸为溶剂, 乙酰丙酮钴为催化剂, 含酰亚胺基团化合物为 助催化剂, 采用空气氧化环己烷合成环己醇 /酮和己二酸; US7507856B2 ( 2009 ) 提出以 4-叔 丁基苯甲酸为溶剂, 乙酰丙酮锰为催化剂, 环己酮为诱导剂的空气氧化环己烷合成己二酸, 其环己烷转化率和己二酸选择性分别可达 7. 17%和 53. 6%; US 0095258 A1 ( 2012 ) 提出以乙 腈作溶剂, 金属氧化物 (Ti02, Zr02, MgO等) 负载贵金属 (Au, Pd, Pt等) 为催化剂, 采用 分子氧氧化环己烷合成己二酸, 环己烷转化率和己二酸选择性分别为 25%和为 26%。这些方法 虽然避免较严重的乙酸腐蚀性问题, 但环己烷转化率和己二酸选择性均较低, 同时存在还溶 剂和产品的分离难等问题。
近十多年来以分子氧为氧化剂制取己二酸的研究比较集中在无溶剂条件方面。 Raja、 Sankar和 Thomas ( J. Am. Chem. Soc., 1999 ) 报道了以负载过渡金属 Fe、 Mn、 Co等的磷铝 分子筛为催化剂,在无溶剂体系下催化氧化环己烷的研究,其中以 FeAlPO-5的催化效果最佳, 环己烷转化率为 19. 8%, 己二酸的选择性为 32. 3%, 其他主要为环己醇、环己酮和一些酯类物 质。 Yuan等 ( Organic Process Research & Development, 2004) 报道了以金属卟啉为催化 剂, 无溶剂条件下催化氧化环己烷合成己二酸的研究, 己二酸的产率为 21. 4%。 最近, LU、 Ren 和 Liu ( Appl ied Catalysis A, 2012 ) 提出 了采用 Anderson 型催化剂 [ (C18¾7) 2N (CH3) 2] 6Mo7024, 在无溶剂条件下催化氧化环己烷合成己二酸的研究, 环己烷转化率 和己二酸选择性分别可达 10. 2%和 87. 1% 。
对于硝基环己烷的合成, 目前主要还是采用传统的混酸硝化方法, 即以硝-硫混酸或硝酸 -醋酐等作为硝化剂对环己烷进行硝化反应。 该方法的选择性差, 存在氧化、 水解、 羟基化等 多种副反应, 因此后处理过程复杂, 而且产生大量含有机化合物的废酸和废水, 治理费用高, 环境污染问题严重, 与清洁化生产的要求相距甚远。
由于烷烃的硝化反应比较复杂, 而且目前硝基环己烷的市场需求远不如己二酸大, 所以 关于环己烷硝化方法的研究与开发的报道较少。 采用 x > 1的 N0X (氮氧化物) 作为硝化剂直 接进行气相硝化烷烃的合成方法, 能够避免使用大量的硫酸, 反应产物中的游离酸少, 分离 容易, 排放少, 但也会伴随生氧化副反应, 主要副产物有相应的醇、 醛、 酮、 酸或硝酸酯和 亚硝酸酯,以及深度氧化副产物 C02和 ¾0等。加拿大专利 CA710356(A)和美国专利 US 3255262 (A)报道了一种环己烷气相硝化合成硝基环己烷的方法: 主要以提高硝基环己烷的产率为目 的, 反应温度为 220-375°C, 停留时间为 20-150秒。 这些方法的主要问题是容易生成大量的 深度氧化副产物 C02和 0, 基于环己烷的产率较低。 最近, CN101781217A ( 2010 ) 提出了一 种利用 N02与环己烷进行气相无催化或气固催化硝化氧化反应联产硝基环己烷和己二酸的方 法, 目的是硝基环己烷和己二酸两种产品的产率最大化, 但其主要产物为硝基环己烷, 己二 酸较少 (选择性一般小于 22%) , 且同样避免不了比较多的深度氧化副产物 C02和 C0。 Hoot 和 Kobe ( Ind. Eng. Chem. , 1955 ) 曾经报道过在较低温度 (50_90°C ) 下将环己烷和 N02封 入一个玻璃管反应一段时间, 主要生成己二酸, 其次是硝基环己烷和其它二元酸。 但是, 环 己烷转化率低(约 2. 5%) 、 反应时间较长、 主要产物(己二酸和硝基环己烷) 的总选择性低, 且己二酸选择性随温度升高而急剧降低。 例如: 当反应温度为 50°C时, 反应时间 40多小时, 己二酸选择性约 76%, 硝基环己烷选择性约 3%, 两者总选择性约 79%; 当反应温度为 80°C时, 反应时间缩短到 3小时, 己二酸选择性下降到约 40%, 硝基环己烷选择性上升到约 7%, 两者 总选择性约 47%; 当反应温度为 90°C时, 反应时间缩短到约 50分钟, 但己二酸选择性几乎为 0, 硝基环己烷选择性约为 22%。 发明内容 本发明旨在提供一种以 N0X ( 1 < X < 3, 下同) 为硝化氧化剂, 将环己烷一步转化, 高 选择性联产己二酸和硝基环己烷的方法。 对比目前以环己烷为原料的己二酸和硝基环己烷的 工业生产技术, 它不仅可以大幅度简化生产流程和设备, 更重要的是能够大幅度提高资源利 用率、 减少环境污染、 降低能耗和生产成本, 是实现己二酸和硝基环己烷绿色合成的一个新 途径。 本发明的方法更适宜于连续化生产。
本发明的基本原理和方法如下:
对于一般有机化合物来说, 由于 N0X既是一种硝化剂, 也是一种氧化性较强的氧化剂, 在 一定条件下, 可与 N0X发生硝化反应和氧化反应。 例如, N0X与环己烷可以发生硝化反应生成 硝基环己烷, 同时还可以将环己烷氧化为己二酸, 反应式如下:
Figure imgf000005_0001
C6H12 -N0X → (CH2 )4 (C00H)2 + H20 + ^-NO
x - 1 x - 1
由于这两个反应都有水的生成, 所以还存在生成硝酸或亚硝酸等反应, 如:
3N02 + H20——► 2HN03 + NO
Figure imgf000005_0002
3N 0, + H 0—— ^2HN03 + 4NO 除上述反应之外, 还可能发生一些其他的副反应, 生成醇、 酮、 酸、 酯等氧化副产物, 甚至深度氧化产物 CO和 co2。 如果反应控制不当, 就可能严重影响主要产品的产率。 不过, 反应所生成的 NO可以回收后配入一定量的 02循环利用:
NO + ^02 —— > NOx
2 2 x
由于这个 NO和 的反应是一个自发反应, 因此从上述制备己二酸的角度看, 是以 NO为 载体引入分子氧为氧化剂的一个绿色化学过程; 同理, 上述制备硝基环己烷也同样是一个绿 色化学过程。
因此, 本发明的方法是以氮氧化物 N0X为氧化剂和硝化剂, 以反应温度、 反应压强、 反应 物配比和催化剂或诱导剂等反应条件为调控手段, 将环己烷一步转化, 高选择性、 可调节比 例联产己二酸和硝基环己烷,而反应产生的 NO则在回收后配入一定量的 02生成 NO 环利用。 催化剂或诱导剂的主要作用是提高环己烷转化率和 N0 l」用率,并辅助调节产物己二酸和硝基 环己烷的比例。 根据本发明的第一个实施方案, 提供一种由环己烷一步转化高选择性联产己二酸和硝基 环己烷的方法, 其特征在于: 以 N0X ( 1 〈 X 〈 3, 下同) 为氧化剂和硝化剂对环己烷同时进 行氧化和硝化反应, 高选择性联产己二酸和硝基环己烷, 并通过调节环己烷转化条件来实现 己二酸与硝基环己烷的生成比例的调控, 己二酸选择性可在 5%-95%之间调节。 一般, 该方法在一种生产装置中进行, 该装置包括环己烷转化***、 NO氧化***、 相分 离***、 轻相物料分离***和重相物料分离***, 其中氧化和硝化反应是在环己烷转化*** 中进行, 反应所生成的 NO的氧化是在 NO氧化***中进行, 在氧化和硝化反后获得的反应混 合物在相分离***中进行分离而获得轻相物料和重相物料。 对于本发明, 在转化***中例如密闭式反应器 (非管式反应器如高压反应釜, 或管式反应 器)中将环己烷与 N0X在液相或气液相状态下进行氧化和硝化反应。 通常, 环己烷转化***的转化反应温度在 0-150°C, 优选 5-100°C ; 转化***反应压强在 常压 -10 MPa, 优选常压 -3 MPa; 反应物环己烷与 N0X的摩尔比为 0. 1-20, 优选 0. 2-10; N0X 为 1 〈 X 〈 3的氮氧化物, 如 N02、 N204、 N203、 N205等或它们的混合物, 优选 1. 5 〈 x 〈 3。 在以上所述的方法中, 从环己烷转化***出来的反应产物通过相分离***可将其分为轻 相物料和重相物料; 其轻相物料主要为未转化的环己烷以及溶于其中的硝基环己烷, 通过轻 相物料分离***将未转化的环己烷分离出来后可得硝基环己烷粗品, 而分离出的环己烷则可 循环利用; 其重相物料主要为反应生成的己二酸晶体, 固体催化剂和少量酸性水相, 通过重 相物料分离***可得己二酸粗品。 优选地, 从环己烷转化***出来的气态产物 N0, 经过 N0氧化***将其转化为 N0X ( 1〈 X 〈3) 再循环使用; 为了防止微量不凝性气体在***中累积, 可取少量气态产物作为尾气进行 处理。 优选地, 环己烷转化反应可以加入催化剂或诱导剂, 目的是提高环己烷转化率和总选择 性, 并辅助调节产物己二酸和硝基环己烷的比例; 采用固态催化剂时, 其与环己烷的质量比 为 0-0. 2; 采用液态催化剂或诱导剂时, 其与环己烷的质量比为 0-0. 1。 一般, 催化剂或诱导剂的种类为钒磷氧复合物类、 酰亚胺类化合物、 分子筛类、 固体酸 类、 金属氧化物类、 有机或无机酸盐类、 Salen 过渡金属类催化剂、 杂多酸类、 过氧化物类 以及醇、 酮、 醛、 酯类化合物等等; 来自相分离***轻相物也可作为诱导剂。 优选地, 固态催化剂从重相物料分离***分离出来后, 可直接或间接循环回环己烷转化 ***使用。
另外,本发明的方法是以氮氧化物 N0X为氧化剂和硝化剂,通过液相或气液相反应从环己 烷一步高选择性联产己二酸和硝基环己烷的方法。 以反应温度、 反应压强、 反应物配比和催 化剂或诱导剂等反应条件为调控手段, 高选择性、 可调节比例联产己二酸和硝基环己烷, 而 反应产生的 NO则在回收后配入一定量的 02生成 N0X循环利用。 催化剂或诱导剂的主要作用是 提高环己烷转化率和 N0 l」用率, 并辅助调节产物己二酸和硝基环己烷的比例。
根据本发明的第二个实施方案,提供从环己烷联产 (或生产)己二酸和硝基环己烷的方法, 该方法包括以下步骤:
(a)反应: 在有或者没有催化剂或诱导剂存在的情况下, 在反应器中将环己烷与 N0X在液 相或气液相状态下进行氧化和硝化反应, 得到含有己二酸和硝基环己烷的反应混合物, 其中 N0X为满足 1 〈 X < 3的氮氧化物中的任意一种或两种或多种的混合物。
优选地, 上述方法进一步包括:
(b)相分离:将步骤 (a)中得到的反应混合物进行相分离 (例如通过静置、沉降或离心处理) 从而分成轻、 重两相, 其中轻相包括硝基环己烷、 未反应的环己烷和任选的诱导剂, 重相包 括反应生成的酸水相、 己二酸晶体和任选的催化剂。 其中上层轻相也称作油相, 下层重相也 称作水相。
更优选地, 上述方法进一步包括:
(c)二级分离: (cl)从步骤(b)所得到的轻相中分离出未反应的环己烷和任选的诱导剂, 得到含少量副产物的硝基环己烷粗品, 和 /或 (c2)从步骤 (b)所得到的重相中分离出己二酸 晶体粗品和任选的催化剂,剩余的酸水相进行后处理以便回收其中的硝酸及少量酸性副产物。
优选地, 上述方法进一步包括:
(d)循环: 将(a)中反应得到的气体相(例如在反应过程中或在反应完成之后)送去 NO氧 化反应器中与 发生反应, 使其中的 NO转变 N0X ( 1 < X < 3) 以便循环利用(例如循环回到 反应器中或被贮存于容器中以便用于下一批次的反应)。 另外, 由 (b ) 得到的轻相中含有诱 导剂以及少量有诱导作用的醇、 酮、 酯等副产物, 取少量的轻相直接作为诱导剂循环使用。 此外, 将 (c ) 中分离得到催化剂直接使用或间接循环使用(即经过提纯或再生后再使用)。
在本申请中 "任选"表示有或没有。
在本申请中步骤 (a)中所使用的反应器一般是密闭式反应器, 优选是非管式反应器, 更优 选是高压釜式反应器或高压反应釜。优选, 以上所述的反应器是一个密闭式反应器 (非管式反 应器)如高压釜式反应器或高压反应釜,或是两个或三个或四个或五个或六个或七个或八个或 更多个串联的密闭式反应器如高压釜式反应器或高压反应釜。或另外, 步骤 (a)中所使用的反 应器是密闭式反应器, 例如管式反应器。 以上所述的反应器优选是由不锈钢制造的。 这里所 述的反应器优选是管式反应器或塔式反应器,也可以是单釜式反应器或多釜串联反应器等等。
优选, 在以上所述的反应器中使用混合设备 (如搅拌桨或搅拌棒)进行混合, 例如对于非 管式反应器而言使用动态混合设备如搅拌桨或搅拌棒或对于管式反应器而言使用静态混合设 备或静态混合器。
当步骤 (a)中所使用的反应器是一个反应器时, 本发明的方法能够以间歇方式进行。 当步 骤 (a)中所使用的反应器是两个或三个或四个或五个或六个或七个或八个或更多个串联反应 器(如压釜式反应器或高压反应釜), 或者是管式反应器时, 本发明的方法能够以半连续方式 或连续方式进行。
在以上所述的方法中,所述步骤 ( a)的反应温度是 0-150°C,优选 5-140°C,优选 10_130°C, 优选 20-120°C, 优选 30-110°C, 优选 40_10(TC, 优选 45-90°C或 40_95°C, 优选 50-80°C或 60-85 °C, 进一步优选 55-75 °C或 65-82 °C, 再优选 58-70°C或 70_80°C。
在以上所述的方法中, 其中在所述步骤 (a) 中环己烷与 NOx的摩尔比为 0. 1-20 : 1, 优选 0. 15- 15 : 1, 优选 0. 2- 10 : 1, 优选 0. 25- 8 : 1, 优选 0. 3- 6 : 1, 优选 0. 35- 4 : 1, 优选 0. 37-2 : 1, 优选 0. 40-1 : 1, 优选 0. 42-0. 95 : 1, 更优选 0. 45-0. 75 : 1, 更优选
0. 50-0. 70 : 1, 或优选 0. 15-0. 30 : 1, 例如 0. 20 : 1。 所述步骤 ( a) 中 N0X为 1. 5 < x < 3 的氮氧化物, 优选为 N02、 N204、 N203、 N205或其中任意两种、 三种或四种的混合物。
在以上所述的方法中, 其中催化剂与环己烷的质量比为 0-0. 30 : 1, 优选 0. 005-0. 27 : 1, 优选 0. 01-0. 25 : 1, 优选 0. 05- 0. 23 : 1, 优选 0. 08- 0. 22 : 1, 优选 0. 10- 0. 20 : 1, 和 /或诱导剂与环己烷的质量比为 0-0. 25 : 1, 优选 0. 003-0. 23 : 1, 优选 0. 005-0. 20 : 1, 优选 0. 008- 0. 15 : 1, 优选 0. 01- 0. 12 : 1, 优选 0. 02-0. 11 : 1, 优选 0. 03- 0. 10 : 1。
在以上所述的方法中, 其中所述步骤 (a)反应是在 1大气压(即 0. 10133MPa) -10 MPa, 优 选 1. 12大气压 -5 MPa, 优选 1. 15大气压 _4MPa, 更优选 1. 2大气压 _3MPa, 进一步优选 1. 25 大气压 -2. 5MPa, 进一步优选 0. 5-1. 5MPa、 0. 8-1. 3MPa、 0. 9-1. 25MPa、 1. 09-1. 20MPa, 例如
1. 18、 1. 13MPa的压力下进行的。
优选地,当步骤 (a)的反应在 40— 95°C下进行时,压力一般是在 1大气压至 1. 3MPa之间; 当步骤 (a)的反应在 50— 85 °C下进行时, 压力一般是在 1. 5大气压至 1. 25MPa之间; 当步骤 (a)的反应在 60— 80°C下进行时, 压力一般是在 0. 6 - 1. 18MPa之间(例如 0. 7或 0. 8或 0. 9 或 1. 13MPa); 或当步骤(a)的反应在 60— 75 °C下进行时, 压力一般是在 0. 6 - 1. IMPa之间(例 如 0. 7或 0. 8MPa); 或当步骤(a)的反应在 70— 80°C下进行时, 压力一般是在 1. 08 - 1. 14MPa 之间(例如 1. 13MPa)。
在以上所述的方法中, 其中所述步骤 (a)的反应时间(或停留时间)一般是 0. 5-30小时, 优选 1-28小时(例如 15, 20, 24, 26小时),优选 1. 5-25小时,优选 2. 0-20小时,优选 2. 5-18 小时, 例如 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16小时。
当本发明的方法以半连续方式或连续方式进行时, 在两个或三个或四个或五个或六个或 七个或八个或更多个串联反应器(如压釜式反应器或高压反应釜)中或在管式反应器中的总停 留时间是步骤 (a)中的反应时间。
优选的是,在本发明的方法中, "在反应器中将环己烷与 N0X在液相或气液相状态下进行 氧化和硝化反应"是指将液态 N0X与环己烷混合 (例如将液态 N0X溶解在环己烷中), 在升高的 温度下和在搅拌或充分混合下进行氧化和硝化反应。 更优选的是, 在本发明的方法中, "在 反应器中将环己烷与 N0X在液相或气液相状态下进行氧化和硝化反应"是指将液态 N0X与环己 烷混合 (例如将液态 N0X溶解在环己烷中),在升高的温度下和在搅拌设备的充分搅拌作用下或 在利用静态混合设备的充分混合作用下进行氧化和硝化反应。
本发明所述的 "气液相状态下"是指在反应器内既有液态反应混合物, 同时在反应混合 物的上部或液面之上存在气相(含有或主要含有反应所产生的 NO气体)。
优选的是, 在以上步骤 (a)中, 将液态 N0X在低于 20°C、 优选低于 15°C (例如低于 5°C)的 温度下溶解于环己烷中形成反应混合物。 优选, 所形成的反应混合物在密闭的反应器中在升 高的温度 (如以上所述的反应温度)下进行反应。更优选, 步骤 (a)的反应是在充分混合或搅拌 的情况下进行的。
优选地,以上所述的步骤 (a)反应如下进行:在有或者没有催化剂或诱导剂存在的情况下, 在低于 20°C、 优选低于 15 °C的温度下将 N0X溶解于环己烷中, 然后在反应器中在升高的温度 (如以上所述的反应温度)下 (优选, 在升高的压力下, 和 /或在混合或搅拌下)在液相或气液相 状态下进行氧化和硝化反应, 得到含有己二酸和硝基环己烷的反应混合物, 其中 N0X为满足 1 < X < 3的氮氧化物中的任意一种或两种或多种的混合物。
本发明发现很多物质都可以起催化或诱导作用, 并且不同的催化剂或诱导剂可调节己二 酸与硝基环己烷的比例。
在以上所述的方法中, 所述催化剂是选自以下物质组中的一种或两种或多种的混合物: 钒磷氧复合物类如 M-VP0或 M-A1VP0 (其中 M为过渡金属, 如 Mn、 Cu、 Co、 Ni或 Cr); 酰亚胺 类化合物如 N-羟基邻苯二甲酰亚胺、 N-N' 二羟基均苯四酸二甲酰亚胺或 N-羟基 -1, 8-萘二 甲酰亚胺 (它们优选与作为酰亚胺类化合物的助剂的 9, 10-蒽醌、 1-氨基蒽醌或 2-氨基蒽醌相 结合使用); 过渡金属(如 Mn、 Cu、 Co、 Ni或 Cr) 乙酰丙酮络合物类催化剂; 沸石类或分子 筛类如 HZSM-5分子筛、 H-Y分子筛、 β -沸石、 TS-1钛硅分子筛或 MA1P0-5分子筛(其中 Μ为 Fe、Mn、Mg、Co或 Cu);固体酸类如磺酸树脂、硫酸 /硅胶、磷酸 /硅胶以及 S04 2—/ [Ti02 (4) -Mo03 (1) ] 或 S04 2—/Zr02- Ce203 ; 金属氧化物类如 Ti02、 V205、 γ - A1203、 Zr02、 NiO、 CrO、 Mn02、 CuO、 Ce203、 ¥03或 Co304/Si02-Al203 ; 有机或无机酸盐类, 例如过渡金属的醋酸盐(如醋酸锰、 醋酸钴、 醋 酸铜)、 过渡金属的环烷酸盐 (如环烷酸钴)、 过渡金属的硫酸盐 (如硫酸锰、 硫酸钴、 硫酸镍、 硫酸铜或 Fe2 (S04) 3)、 过渡金属的盐酸盐 (如氯化钴、 氯化铜或氯化锌); Salen过渡金属类催 化剂如双水杨醛叉乙二胺合钴(Cosalen)、Cosalen/NaY、Cosalen/AlP0-5或 Cosalen/MCM-41 ; 杂多酸类如 HPAs或磷钨酸; 或诱导剂是选自以下物质组中的一种或两种或多种的混合物: 过 氧化物类如过氧苯甲酰、 双氧水或叔丁基过氧化氢, 以及醇、 酮、 醛或酯类化合物, 如: 环 己酮、 丁酮、 丙酮; 环己醇、 戊醇、 丁醇、 丙醇、 乙醇、 甲醇; 丁醛、 丙醛、 乙醛; 乙酸乙 酯、 乙酸正丁酯、 硝酸乙酯。
优选的是,催化剂是钒磷氧复合物类如 M-VP0或 M-A1VP0 (其中 M为过渡金属,如 Mn、 Cu、 Co、 Ni或 Cr)。
在本发明中,在反应之前或反应开始时将 N0X (例如在较低温度如低于 20°C、优选低于 15°C 或低于 5°C)下)溶解在环己烷中形成液态反应混合物, 然后在密闭的反应器中在升高的温度 下继续以液体混合物的形式进行反应, 尤其在反应过程中或在反应的同时进行充分混合或搅 拌。 本发明人出乎预料地发现, 以非常高的转化率和选择性获得了己二酸。
通过本发明所述的方法, 环己烷的单程转化率可达 20-60%、优选 30-50%, 主要产物己二 酸和硝基环己烷的的总选择性可达 98% (或 99%) -99. 9%或甚至 100%。 两者的比例可调, 己二 酸的选择性一般是在 60-90%或 63-85%范围, 例如可达到 70%、 80%或 85%或 90%以上 (选择性 均是基于环己烷) 。 己二酸的纯度可达 98wt%以上。
在本申请中的压强或压力是指绝对压力(单位: 大气压或 MPa)。 本发明的方法能够以间歇、 半连续或连续的方式进行。
下面参照附图 1对本发明的方法加以说明。 附图 1描述的是一个间歇过程, 但也可以是 一个连续的过程, 该方法更适合连续化生产。
( I )本发明方法主要由环己烷转化***(Rl ) 、 NO氧化***(R2)、相分离***(S1 ) 、 轻相物料分离*** (S2) 和重相物料分离*** (S3) 等五个部分组成。
( II )环己烷 (1 )和 N0X ( 2)在环己烷转化*** (R1 ) 中发生氧化和硝化反应, 主要生 成己二酸和硝基环己烷。转化***反应温度在 0-150°C, 优选温度为 5-100°C ; 转化***反应 压强为常压 -10 MPa, 优选压强为常压 -3 MPa; 环己烷 (1 ) 与 N0X ( 2) 的摩尔比为 0. 1-20, 优选摩尔比为 0. 2-10; 当采用固态催化剂时, 反应体系为液固两相或气液固三相, 固态催化 剂与环己烷的质量比为 0-0. 2; 当采用液态催化剂或诱导剂时, 反应体系为液相或气液两相, 液态催化剂或诱导剂与环己烷的质量比为 0-0. 1; 物料流 (3) 为新加入的催化剂或诱导剂。
( III )从环己烷转化***(R1 )出来的反应产物经相分离***(S1 )可分为轻相物料(5) 和重相物料 (8) 。 轻相物料 (5) 主要为未转化的环己烷以及溶于其中的反应产物硝基环己 烷; 重相物料 (8) 主要为反应产物己二酸晶体, 固态催化剂, 以及反应生成的酸性水相。
( IV) 通过轻相物料分离*** (S2) 从轻相物料 (5) 中分离出未转化的环己烷 (7 ) 返 回再进入环己烷转化*** (R1 ) , 剩余的为硝基环己烷粗品 (6 ) 。 由于轻相物料 (5 ) 中含 有溶于其中的诱导剂以及少量有诱导作用的醇、 酮、 酯等副产物, 因此也可分出少量的轻相 物料 (12) 直接送入环己烷转化***以诱导环己烷的转化反应。
(V)通过重相物料分离*** (S3) 从重相 (8) 中分离出己二酸晶体粗品 (9)和固态催 化剂 (10) 后, 剩余的酸性水相 (11 ) 需进行后处理, 回收硝酸及其他少量副产物。 分离出 的固态催化剂 (10) 可以直接或间接循环使用。
(VI ) 在环己烷转化反应*** (R1 ) 中产生的气体 (13) 将被回收利用, 其中大部分气 体 (14) 送去 NO氧化反应*** (R2) , 与 (4) 发生反应, 使其中的 NO转变 N0X (x > 1 ) 后循环至环己烷转化***回用 (15) 。 对于连续化过程, 为了防止微量不凝性气体在***中 累积, 需要从气体 (13) 中分出少部分去进行尾气处理 (16) 。
(VII )催化剂或诱导剂的主要作用是提高环己烷转化率和总选择性, 并辅助调节产物己 二酸和硝基环己烷的比例, 因此是根据需要来添加或不添加催化剂或诱导剂。 本发明发现很 多物质都可以起这种催化或诱导作用, 其中主要有以下物质或它们的混合物:
钒磷氧复合物(VP0或 A1VP0)及其改性催化剂, 如 M-VP0或 M-A1VP0, 其中 M为 Mn、 Cu、 Co、 Ni、 Cr等过渡金属氧化物; N-羟基邻苯二甲酰亚胺、 N-N' 二羟基均苯四酸二甲酰亚胺、 N-羟基 -1, 8-萘二甲酰亚胺等酰亚胺类化合物, 其助剂为 9, 10-蒽醌、 1-氨基蒽醌、 2-氨基 蒽醌等蒽醌类化合物; 乙酰丙酮络合过渡金属 (Mn、 Cu、 Co、 Ni、 Cr等) 类配合物催化剂; 分子筛类如 HZSM-5、H-Y分子筛、 β -沸石、钛硅分子筛 TS-1及负载金属类磷铝分子筛 MA1P0-5 (Μ为 Fe、 Mn、 Mg、 Co、 Cu等的氧化物) ; 固体酸催化剂类如磺酸树脂、 硫酸 /硅胶、 磷酸 / 硅胶以及 S04 27[Ti02 (4) -Mo03 (l) ]、 S04 2—/Zr02-Ce203等等; 金属氧化物类催化剂如 Ti02、 V205、 Y - A1203、 Zr02、 Ni0、 Cr0、 Mn02、 Cu0、 Ce203、 W03、 Co304/Si02_Al203等; 有机酸盐或无机酸盐 类催化剂, 如醋酸锰、 醋酸钴、 醋酸铜、 环烷酸钴等过渡金属的醋酸盐, 硫酸锰、 硫酸钴、 硫酸镍、 硫酸铜、 Fe2 (S04) 3等过渡金属硫酸盐以及氯化钴、 氯化铜、 氯化锌等过渡金属的盐 酸盐等; Salen过渡金属类催化剂, 如双水杨醛叉乙二胺合钴 (Cosalen) 及其复合催化剂如 Cosalen/NaY、 Cosalen/AlP0_5、 Cosalen/MCM-41等; 以及杂多酸催化剂如 HPAs和磷钨酸等 等; 过氧化物, 如过氧苯甲酰、 双氧水、 叔丁基过氧化氢等; 酮类, 如环己酮、 丁酮、 丙酮 等; 醇类, 如环己醇、 戊醇、 丁醇、 丙醇、 乙醇、 甲醇等; 醛类如丁醛、 丙醛、 乙醛等; 酯 类, 如乙酸乙酯、 乙酸正丁酯、 硝酸乙酯等等。
上述过程所述的转化***可以是管式反应器、 塔式反应器等, 也可以是单釜式反应器或 多釜串联反应器等等。
通过本发明所述的方法, 环己烷的单程转化率可达 20-70%, 主要产物己二酸和硝基环己 烷的总选择性 (基于环己烷) 可达 95%以上, 其比例可调, 己二酸的选择性 (基于环己烷) 可达到 85%以上。
相对现有的己二酸和硝基环己烷的工业生产工艺和技术, 本发明的环己烷一步转化联产 己二酸和硝基环己烷方法不仅可以大幅度简化生产流程和设备, 更重要的是可以大幅度提高 环己烷的转化率以及己二酸和硝基环己烷的选择性, 从源头上大幅度减少废弃物产生和环境 污染, 同时大幅度节约资源、 降低能耗和降低生产成本。 尤其以相对简单的方式出乎预料地 以高的选择性获得价值高的己二酸。 附图说明 图 1为环己烷硝化氧化一步高选择性联产己二酸和硝基环己烷工艺流程。 具体实施方式 以下实施例旨在说明本发明, 而不是对本发明的限制。实施例中描述的是一个间歇过程, 但其连续化过程也是不受限制的, 并且该方法更适合于连续化生产。
实施例 1 : 按环己烷与 N02的摩尔比 0. 2 : 1、 环己烷与催化剂的质量比 1 : 0. 1, 在 0. 2 L 高压反应釜中加入 5. 04 g环己烷、 13. 80 g液态 N02和 0. 54 g催化剂 Cr_AlVP0; 在 80°C和 2. 0 MPa以及搅拌条件下反应 24 h。 静置冷却后分层, 上层为油相, 主要含未反应的环己烷 和产物硝基环己烷, 下层主要为己二酸晶体、 催化剂固体以及反应生成水等的混合物; 将全 部物料过滤并分别用定量的环己烷和蒸熘水洗涤滤饼; 将收集的滤液及洗涤液进行分液得到 油相和水相并分别计量, 对油相采用气相色谱内标法定量测定其组成, 对水相液相色谱外标 法测定其组成; 将滤饼用定量的甲醇溶解, 过滤出催化剂固体, 计量并用液相色谱外标法定 量分析其滤液。根据物料衡算可得环己烷转化率 60. 3%, 己二酸选择性 84. 4%, 硝基环己烷选 择性 11. 3%, 两者选择性之和 95. 7%。
实施例 2: 如实施例 1, 不同的之处在于, 反应温度为 100°C, 反应压力为 2. 9 MPa。 得 环己烷转化率 75. 4%,己二酸选择性 81. 7%,硝基环己烷选择性 11. 5%,两者选择性之和 93. 2%。
实施例 3: 如实施例 1, 按环己烷与 N02的摩尔比 1 : 1. 0加入 8. 40 g环己烷和 4. 60 g液 态 N02, 催化剂为 VP0; 反应温度为 60°C, 反应压力为 0. 6 MPa。 得环己烷转化率 11. 1%, 己 二酸选择性 80. 6%, 硝基环己烷选择性 11. 9%, 两者选择性之和 92. 5%。
实施例 4: 如实施例 1, 不同的之处在于, 不加催化剂。 得环己烷转化率 18. 6%, 己二酸 选择性 63. 1%, 硝基环己烷选择性为 23. 2%, 两者选择性之和 86. 3%。
实施例 5: 如实施例 1, 不同的之处在于, 按环己烷与 N02的摩尔比 3 : 1, 加入 19. 6 g环 己烷和 3. 58 g液态 N02, 不加催化剂。 环己烷的转化率为 9. 60 %, 己二酸的选择性为 53. 2 %, 硝基环己烷的选择性为 32. 0 %, 两者选择性之和 85. 2%。
实施例 6: 如实施例 1, 不同的之处在于, 采用不同的固态催化剂, 相应得到的环己烷转 化率、 己二酸选择性和硝基环己烷选择性等数据, 如下表: 序 环己垸 选择性 /%
催化剂
转化率 /% 己二酸 硝基环己垸 合计
1 Ni-AlVPO 46. 0 72. 7 25. 3 98. 0
2 V205 58. 5 82. 7 12. 7 95. 4
3 Fe2 (S04) 3 54. 3 80. 5 13. 0 93. 5
4 NiO 55. 8 80. 1 13. 1 93. 2
5 0. 5% Aw/Al203 53. 2 79. 7 14. 4 94. 1
6 NHPI 50. 7 80. 5 13. 7 94. 2
7 乙酰丙酮-铜 48. 2 80. 5 13. 1 93. 6
8 FeAlPO 52. 1 81. 4 13. 3 94. 7
9 硫酸 /硅胶 49. 5 80. 4 13. 3 93. 7
10 钛硅分子筛 TS-1 47. 8 81. 7 12. 9 94. 6
11 钛硅分子筛 Cosalen/MCM-41 49. 1 82. 1 12. 2 94. 3
12 S042-/Zr02-Ce203 54. 1 82. 4 12. 6 95. 0
13 磷钨酸 49. 9 79. 5 14. 0 93. 5 实施例 7: 如实施例 1, 不同的之处在于, 加入环己烷质量的 0. 5%的诱导剂环己酮, 反 应温度为 80°C, 反应压力 1. 9 MPa。 得环己烷转化率 55. 3%, 己二酸选择性 81. 7%, 硝基环己 烷选择性 12. 6%, 两者选择性之和 94. 3 %
实施例 8: 如实施例 1, 不同的之处在于, 在 5. 0 L不锈钢高压釜中, 加入 553. 3 g液态 N02 202. 0 g环己烷和 4. 0 g催化剂 Ni-AlVP0。 静置冷却后, 先取样分析气相组分, 然后通 过排气法计量气体物料约 429. 3 g, 其中主要为 N02 ( 215. 3 g) NO ( 213. 7 g) 以及微量的 环己烷和 C02 ;气体排净后,将全部液态和固态物料计量后再通过抽滤进行固液分离,得 133. 1 g滤液和 193. 5 g滤饼; 滤液通过分液得到 98. 4 g有机相和 34. 7 g水相, 其中有机相主要 含环己烷 (78. 5 wt%) 和硝基环己烷 (20. 8 wt%) 以及少量硝酸环己酯 (0. 32 wt%) 和其它 氧化产物 (0. 38 wt%) , 水相主要含硝酸 (19. 7 wt%) 和少量 4-6 碳二元酸 (2. 9 wt%) 及 4-5碳二元酸酐 (2. l wt%) ; 滤饼先用定量的甲醇溶解, 再过滤分离出固体催化剂, 滤液计 量后取样分析, 除甲醇之外主要含己二酸(96. 3 wt%) 以及少量的丁二酸和戊二酸(3. 5 wt%) 及丁二酸酐和戊二酸酐 (0. 2 wt%) ; 将此甲醇溶液进行减压蒸熘、 水洗、 干燥后得纯度为 99. 6%的己二酸产品。 由物料衡算得环己烷转化率 61. 46%, 己二酸选择性 84. 6%, 硝基环己烷 选择性 10. 8%
实施例 9: 首先将液态的 N02溶于冷的(低于 15°C)环己烷中, 配成均相溶液, 环己烷与 N02的摩尔比为 1 : 1。 再转移至不锈钢高压反应釜中, 然后加入一定量的催化剂 Cr-AlVP0, 环 己烷与催化剂质量比为 1 : 0. 1 ; 密封, 加热搅拌进行氧化反应。 反应温度 60 °C, 反应压力 0. 8MPa (表压), 反应时间 24 h。 反应结束后, 让反应混合物静置冷却至室温, 反应器内上 部的含有 N0的气相被直接引入到氧化反应器中用纯 02进行氧化, 将 N0氧化成 NOx (1 < X < 3); 或该气相被收集到贮存容器中贮存, 一直到在经过多批次的反应后收集到足够量的气体 之后将贮存容器内的气体通入到氧化反应器中用纯 02进行氧化, 将 N0氧化成 NOx (1 < X < 3)回用。 硝化产物硝基环己烷溶于上层油相, 下层主要为己二酸、 少量氧化产物和催化剂, 己二酸以晶体形式析出沉积下来; 油相采用气相色谱法内标法定量分析, 下层用有机溶剂溶 解后分离出己二酸, 液相色谱外标法定其含量。 采用物料平衡法计算环己烷的转化率为 11. 2 %, 己二酸选择性为 80. 7 %, 硝基环己烷选择性 11. 9%, 二者的总选择性为 92. 6% (选择性均 是基于环己烷) 。
实施例 10: 反应步骤如实施例 9, 不同的之处在于, 加入复合氧化物催化剂 Co-AlVPO, 环己烷与 N02的摩尔比为 0. 2 : 1,反应温度为 100 °C,反应压力 2MPa。环己烷的转化率为 85. 3 %, 己二酸的选择性为 80. 5 %, 硝基环己烷的选择性为 11. 4 %, 二者的总选择性为 91. 9 %。

Claims

权 利 要 求
1. 从环己烷高选择性联产己二酸和硝基环己烷的方法, 该方法包括以下步 骤:
(a)反应: 在有或者没有催化剂或诱导剂存在的情况下, 在反应器中将环己烷 与 NOx在液相或气液相状态下进行氧化和硝化反应, 得到含有己二酸和硝基环 己烷的反应混合物, 其中 NOx为满足 1<χ<3 的氮氧化物中的任意一种或两种或 多种的混合物; 和
(b)相分离: 将步骤 (a)中得到的反应混合物进行相分离从而分成轻、 重两相, 其中轻相包括硝基环己烷、未反应的环己烷和任选的诱导剂, 重相包括反应生成 的酸水相、 己二酸晶体和任选的催化剂。
2. 根据权利要求 1的方法, 进一步包括:
(c)二级分离: (cl)从步骤(b)所得到的轻相中分离出未反应的环己烷和任选 的诱导剂, 得到含少量副产物的硝基环己烷粗品, 和 /或 (c2)从步骤 (b) 所得到 的重相中分离出己二酸晶体粗品和任选的催化剂,剩余的酸水相进行后处理以便 回收其中的硝酸及少量酸性副产物。
3. 根据权利要求 1或 2的方法, 进一步包括:
(d)循环: 将 (a)中反应得到的气体相送去 NO氧化反应器中与 02发生反应, 使其中的 NO转变 NOx(l<x<3)以便循环利用。
4. 根据权利要求 1-3 中任何一项的方法, 其中所述步骤 (a) 的反应温度是 0-150°C, 优选 5-140°C, 更优选 40-100°C。
5. 根据权利要求 1-4中任何一项的方法,其中在所述步骤 (a)中环己烷与 NOx 的摩尔比为 0.1-20: 1 , 优选 0.2-10: 1或 0.15-0.30: 1。
6. 根据权利要求 1-5 中任何一项的方法, 其中催化剂与环己烷的质量比为 0-0.30: 1, 优选 0.005-0.27: 1 , 和 /或诱导剂与环己烷的质量比为 0-0.25: 1 , 优选 0.003-0.23: 1。
7. 根据权利要求 1-6中任何一项的方法,其中所述步骤 (a)反应是在 1大气压 -lOMPa, 优选 1.12大气压 -5MPa的压力下进行的。
8. 根据权利要求 1-7中任何一项所述的方法,其特征在于所述催化剂是选自 以下物质组中的一种或两种或多种的混合物: 钒磷氧复合物类, 如 M-VPO 或 M-AIVPO, 其中 M为过渡金属; 酰亚胺类化合物; 过渡金属乙酰丙酮络合物类 催化剂;沸石类或分子筛类;固体酸类;金属氧化物类;有机或无机酸盐类; Salen 过渡金属类催化剂; 杂多酸类; 或诱导剂是选自以下物质组中的一种或两种或多 种的混合物: 过氧化物类, 以及醇、 酮、 醛或酯类化合物。
9. 根据权利要求 1-8中任何一项的方法, 其中该方法是以间歇、 半连续或连 续的方式进行的, 更优选的是该方法以连续方式进行。
10. 根据权利要求 1-9中任何一项的方法, 其中步骤 (a)中的反应器为密闭式 反应器, 优选的是, 密闭式反应器是由不锈钢制造的。
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