阅读说明：本技术 一种多金属氧酸盐高效催化制备二苯基甲烷二异氰酸酯的方法 (Method for preparing diphenylmethane diisocyanate by high-efficiency catalysis of polyoxometallate ) 是由 韩志成 余焓 吴志康 但德敏 于 2019-04-23 设计创作，主要内容包括：本发明公开介绍了一种多金属氧酸盐催化4,4′-二氨基二苯甲烷和甲醇生成4,4′二苯基甲烷二异氰酸酯的制备方法(其中多金属氧酸盐为Keggin型、Wells-Dawson型、Lindqvist型、Waugh型Anderson型及Silverton型的六大基本构型中的一种,以Anderson型构型为主)。本发明具体步骤为：将M-Anderson型杂多酸(M＝Mn、Fe、Al、Cr、Co、Ni、Cu、Zn等)作为催化剂、4,4′-二氨基二苯甲烷、甲醇、双氧水、缚酸剂、脱水剂及无水乙腈溶剂加入干净的反应管中；最后在反应器上方套上氧气球,在一定温度下,空气磁力充分搅拌反应一段时间后,即可得到目标化合物；本发明方法采用M-Anderson型杂多酸作为催化剂,该类催化剂具有极高的反应活性,且以常见的非贵金属为中心,更具有推广利用的价值并经简单处理后可回收利用,提高了工业反应的清洁性,且减轻了环保压力。(The invention discloses a preparation method for generating 4, 4 '-diphenylmethane diisocyanate by catalyzing 4, 4' -diaminodiphenylmethane and methanol with polyoxometallate (wherein the polyoxometallate is one of six basic configurations of Keggin type, Wells-Dawson type, Lindqvist type, Waugh type Anderson type and Silverton type, and the Anderson type configuration is taken as a main configuration). The method comprises the following specific steps: adding M-Anderson type heteropoly acid (M ═ Mn, Fe, Al, Cr, Co, Ni, Cu, Zn and the like) as a catalyst, 4' -diaminodiphenylmethane, methanol, hydrogen peroxide, an acid-binding agent, a dehydrating agent and an anhydrous acetonitrile solvent into a clean reaction tube; finally, sleeving an oxygen balloon above the reactor, and magnetically stirring the mixture in air at a certain temperature for reaction for a period of time to obtain a target compound; the method adopts M-Anderson type heteropoly acid as the catalyst, the catalyst has extremely high reaction activity, and has more popularization and utilization values by taking common non-noble metal as the center, and can be recycled after simple treatment, thereby improving the cleanness of industrial reaction and lightening the environmental protection pressure.)

1. A preparation method for preparing 4, 4' -diphenylmethane diisocyanate by one-step generation through oxidative coupling of amine compounds and alcohol compounds is characterized by comprising the following steps:

1) adding 4, 4 '-diaminodiphenylmethane and methanol into a container filled with an organic solvent and a catalyst, uniformly mixing, adding hydrogen peroxide, a dehydrating agent and an acid-binding agent into the container, stirring and reacting for 4-24 hours at 0-30 ℃, stopping the reaction after reacting for a certain time, and separating and purifying to obtain the corresponding isocyanate compound, namely 4, 4' -diphenylmethane diisocyanate.

2) And (2) recovering and reusing the catalyst used in the step (1) after simple treatment, and investigating the catalytic activity of the catalyst.

3) Reaction conditions are optimized, and the universality of reaction substrates is explored.

2. The method of claim 1, wherein; in the step 1), the organic solvent is an aprotic polar solvent, the reaction temperature is 0-20 ℃, and the reaction time is 6-12 h.

3. The method of claim 1, wherein: in the step 1), the dehydrating agent is one of phosphorus oxychloride or DMSO.

4. The method of claim 1, wherein: in the step 1), the acid-binding agent is one of triethylamine and pyridine.

5. The method of claim 1, wherein in step 1), the polyoxometalate is in the Anderson configuration and the amount of catalyst is between 0.1 mol% and 5 mol%.

6. The preparation method according to claim 1, wherein in the step 2), after the reaction is finished, the polyoxometallate (polyacid) is precipitated after the organic solvent is added into the phase system, and is recycled after simple treatment, and the recycled polyacid is reused for the oxidative coupling reaction.

7. The method of claim 1, wherein in step 3), the solvent, temperature, additive, amount of oxidant, and amount of catalyst are screened by controlling variables to obtain optimized reaction conditions.

8. The method according to claim 3, wherein the dehydrating agent is phosphorus oxychloride, which can be added directly, and the amount of phosphorus oxychloride is 1 to 3 equivalents.

9. The method according to claim 4, wherein the acid-binding agent is triethylamine, and the acid-binding agent is added to facilitate the forward shift of equilibrium according to the equilibrium shift principle.

10. The process according to claim 5, wherein the catalyst is selected from the group consisting of Fe, Al, Mn, Cu, and the like-centered Anderson polyoxometallates, and Tris derivative (trialkoxy derivative) -modified Fe, Al, Mn, Cu, and the like-centered Anderson polyoxometallates.

Technical Field

The invention relates to the technical field of catalysis, in particular to a method for preparing isocyanate by high-efficiency catalysis of polyoxometallate mainly of Anderson type.

Background

4, 4' -diphenylmethane diisocyanate MDI develops later than TDI, but the curing speed is high, the molding period is short, diversified foam products are easy to develop, MDI-based foam has high density, and a product with better PU foam performance can be prepared by changing the component proportion; meanwhile, MDI has much lower steam pressure, low molding temperature, less environmental pollution, less equipment investment and lower market price than TDI. The method is widely applied to the production field of polyurethane elastomers, and the production field of polyurethane materials such as synthetic fibers, artificial leather, solvent-free coatings and the like. The methods for synthesizing MDI can be mainly classified into two major types, i.e., phosgenation and non-phosgenation, according to the raw materials involved in the reaction.

The Anderson-type polyoxometallate is a highly flexible cluster of POMs allowing modification from multiple angles: firstly it can incorporate a large number of different heteroatoms of different sizes and oxidation states, secondly it can incorporate inorganic or organic cations exhibiting different coordination motifs and secondly, finally, it can be rendered specifically organic by covalent linkage to tris (hydroxymethyl) methane ligands. Polyoxometallate is a polynuclear polymer with a large molecular volume, and has the characteristics of a cage-like structure, and the structure determines a plurality of physicochemical properties of the polyoxometallate, such as strong acidity, high thermal stability, redox catalysis and the like.

Traditionally, diphenylmethane diisocyanate is prepared by condensation and transposition reaction of aniline and formaldehyde (hydrochloric acid is used as a catalyst) under normal temperature and pressure to obtain amine hydrochloride, neutralizing, washing, removing the remaining aniline to generate 4, 4' -diphenylmethane diamine (MDA), carrying out phosgenation reaction of the MDA and phosgene under high temperature and pressure to generate reaction liquid containing MDI, and finally carrying out rectification separation under vacuum to obtain pure MDI, polymeric MDI and other series products. Patent CN1966489B discloses an invention method for preparing diphenylmethane diisocyanate by a two-step method, which comprises the steps of firstly carrying out acid condensation on aniline and formaldehyde to obtain an amine mixture, then reacting the amine mixture with phosgene, and distilling to obtain the diphenylmethane diisocyanate. Although the phosgenation process for the production of MDI is well established and is currently the method used by MDI producers in the world, it has its inevitable disadvantages, mainly expressed as: the highly toxic phosgene is used as a reaction raw material, so that potential safety hazards exist.

Disclosure of Invention

In order to solve the defects in the prior art, the invention takes 4, 4 '-diaminodiphenylmethane and methanol as raw materials, selects environment-friendly polyoxometallate as a catalyst, adds hydrogen peroxide, an acid-binding agent and a dehydrating agent, and generates the corresponding 4, 4' -diphenylmethane diisocyanate by one-step coupling.

Technical scheme

A preparation method of a catalyst for one-step preparation of 4, 4' -diphenylmethane diisocyanate compounds by oxidative coupling of amine compounds is characterized by comprising the following steps:

1) the preparation method comprises the steps of uniformly mixing an amine compound and derivatives thereof with alcohol in a reaction tube filled with an organic solvent and a catalyst, adding hydrogen peroxide, an acid-binding agent and a dehydrating agent into the reaction tube, stirring and reacting for 6-12 hours at 0-20 ℃, and separating to obtain the corresponding isocyanate compound.

2) The catalyst used in step (1) was recovered and reused, and its catalytic activity was examined.

3) Reaction conditions are optimized, such as adding additives to improve reaction yield, and the universality of reaction substrates is explored.

The oxidative coupling of amines of the present invention is represented by the general formula

In the invention, the organic solvent in the step 1) adopts an aprotic polar solvent such as DMF, DMSO, anhydrous acetonitrile and the like, and the preferred solvent is anhydrous acetonitrile; the reaction time can be between 5h and 15h, and is optimal when 12h is needed; the reaction temperature can be 0-30 ℃, and the effect is optimal when the temperature is 0 ℃; the catalyst can be Anderson type polyoxometallate taking non-noble metals such as Fe, Al, Mn, Cu and the like as the centers, or Anderson type polyoxometallate taking Fe, Al, Mn, Cu and the like modified by Tris derivatives (trialkoxy derivatives) as the center, the amount of the catalyst is more suitable for 0.1-3.0 mol%, and the optimal amount is 1.0 mol%; the acid-binding agent uses triethylamine and phosphorus oxychloride as a dehydrating agent.

In the step 2) of the invention, the recovered catalyst is recycled, after the reaction is finished, organic solvents such as ether and the like are added into a phase system, polyoxometallate (heteropoly acid) is separated out, and is recovered after treatment, and the recovered polyacid is reused for the amine oxidative coupling reaction.

The amount of catalyst, solvent, temperature, amount of catalyst and amount of dehydrating agent for the reaction are screened by controlling variables to obtain optimized reaction conditions.

Compared with the existing method for preparing the diphenylmethane diisocyanate, the method has the following advantages: the method has the characteristics of single and easily obtained raw materials, simple preparation process, low production cost, high product yield, no three wastes and the like, and is a method for preparing the diphenylmethane diisocyanate with high atom economy and environmental friendliness. The catalyst is a novel catalyst, namely Anderson type polyoxometallate (heteropoly acid), the central metal is common non-noble metal, the catalyst can be recycled for a plurality of times after simple treatment, and the selectivity of a substrate is not greatly reduced, which is very favorable for industrial production.

Drawings

FIG. 1 is an Anderson type polyacid infrared modified with infrared polyoxometallate and Tris derivatives based on Anderson type (taking iron as the metal center as an example)

FIG. 2 is an Anderson type polyacid nuclear magnetic resonance modified with Tris derivative (taking iron as the metal center as an example)

FIG. 3 is an SEM image of an Anderson-type polyoxometallate (taking iron as a metal center as an example)

FIG. 4 is an SEM image of an Anderson-type polyacid modified with a Tris derivative (e.g., iron as the metal center)

FIG. 5 is a comparison of XRD of an Anderson-type polyoxometallate with that of a plurality of times recycled (taking iron as a metal center as an example)

Detailed Description

In order to further explain the present invention in detail, several specific embodiments are given below, but the present invention is not limited to these examples.

Example 1

A25 mL clean reaction tube was charged with 0.0240g (0.02mmol) of copper-centered polyoxometallate [ NH ]₄]₄[CuMo₆O₁₈(OH)₆]·7H₂O(CuMo₆) 0.3966g (2mmol) of 4, 4' -diaminodiphenylmethane, 0.0641g (2mmol) of methanol, 0.2041g (6mmol) of hydrogen peroxide, 0.1012g (1mmol) of triethylamine, 0.3067g (2mmol) of phosphorus oxychloride and 6mL of solvent anhydrous acetonitrile, and finally sleeving an oxygen balloon above a reaction tube to react for 12 hours at 0 ℃; after the reaction is finished, the sample is taken to measure GC-MS, the conversion rate of the reaction substrate is more than 91 percent, the selectivity of the product is 90 percent, white molten solid is obtained by separation and purification, and the product is the 4, 4' -diphenylmethane diisocyanate after nuclear magnetism confirmation.

Example 2

A25 mL clean reaction tube was charged with 0.0240g (0.02mmol) of iron-centered polyoxometallate [ NH ]₄]₃[FeMo₆O₁₈(OH)₆]·7H₂O(FeMo₆) 0.3966g (2mmol) of 4, 4' -diaminodiphenylmethane, 0.0641g (2mmol) of methanol, 0.2041g (6mmol) of hydrogen peroxide, 0.1012g (1mmol) of triethylamine, 0.3067g (2mmol) of phosphorus oxychloride and 6mL of solvent anhydrous acetonitrile, and finally sleeving an oxygen balloon above a reaction tube to react for 12 hours at 0 ℃; after the reaction is finished, the sample is taken to measure GC-MS, the conversion rate of the reaction substrate is more than 93 percent, the selectivity of the product is 95 percent, white molten solid is obtained by separation and purification, and the product is the 4, 4' -diphenylmethane diisocyanate after nuclear magnetism confirmation.

Example 3

A25 mL clean reaction tube was charged with 0.0234g (0.02mmol) of chromium-centered polyoxometallate [ NH ]₄]₃[CrMo₆O₁₈(OH)₆]·7H₂O(CrMo₆) 0.3966g (2mmol) of 4, 4' -diaminodiphenylmethane, 0.0641g (2mmol) of methanol,0.2041g (6mmol) of hydrogen peroxide, 0.1012g (1mmol) of triethylamine, 0.3067g (2mmol) of phosphorus oxychloride and 6mL of solvent anhydrous acetonitrile, and finally covering an oxygen balloon above the reaction tube to react for 12h at 0 ℃; after the reaction is finished, the sample is taken to measure GC-MS, the conversion rate of the reaction substrate is more than 89%, the selectivity of the product is 91%, white molten solid is obtained by separation and purification, and the product is the 4, 4' -diphenylmethane diisocyanate after nuclear magnetic confirmation.

Example 4

0.0363g (0.02mmol) of a copper-centered polyoxometalate modified on one side with a Tris derivative [ [ N (C) was added to a 25mL clean reaction tube₄H₉)₄]₄[CuMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]·13H₂O(CH₂OH-CuMo₆) 0.3966g (2mmol) of 4, 4' -diaminodiphenylmethane, 0.0641g (2mmol) of methanol, 0.2041g (6mmol) of hydrogen peroxide, 0.1012g (1mmol) of triethylamine, 0.3067g (2mmol) of phosphorus oxychloride and 6mL of solvent anhydrous acetonitrile, and finally sleeving an oxygen balloon above a reaction tube to react for 12 hours at 0 ℃; after the reaction is finished, the sample is taken to measure GC-MS, the conversion rate of a reaction substrate is more than 90 percent, the selectivity of the product is 91 percent, ether (or ethanol, ethyl acetate and the like) is added into a reaction system, white solid is obtained by filtering, washing and drying, the white solid is collected and recycled, the filtrate is separated and purified to obtain white molten solid, and the product, namely the 4, 4' -diphenylmethane diisocyanate is confirmed by nuclear magnetism.

Example 5

0.0363g (0.02mmol) of an iron-centered polyoxometalate modified on one side with a Tris derivative [ [ N (C) was added to a 25mL clean reaction tube₄H₉)₄]₃[FeMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]·13H₂O(CH₂OH-FeMo₆) 0.3966g (2mmol) of 4, 4' -diaminodiphenylmethane, 0.0641g (2mmol) of methanol, 0.2041g (6mmol) of hydrogen peroxide, 0.1012g (1mmol) of triethylamine, 0.3067g (2mmol) of phosphorus oxychloride and 6mL of solvent anhydrous acetonitrile, and finally sleeving an oxygen balloon above a reaction tube to react for 12 hours at 0 ℃; after the reaction is finished, the sample is takenGC-MS (gas chromatography-mass spectrometry) is carried out, the conversion rate of a reaction substrate is more than 91%, the selectivity of a product is 93%, ether (or ethanol, ethyl acetate and the like) is added into a reaction system, white solid is obtained by filtration, washing and drying are carried out, the white solid is collected and recycled, filtrate is separated and purified to obtain white molten solid, and the product, namely the 4, 4' -diphenylmethane diisocyanate is confirmed by nuclear magnetism.

Example 6

Into a 25mL clean reaction tube was added 0.0363g (0.02mmol) of a chromium-centered polyoxometalate [ N (C) with a single side modification with a Tris derivative₄H₉)₄]₃[CrMo₆O₁₈(OH)₃{(OCH₂)₃CCH₂OH}]·13H₂O(CH₂OH-CrMo₆) 0.3966g (2mmol) of 4, 4' -diaminodiphenylmethane, 0.0641g (2mmol) of methanol, 0.2041g (6mmol) of hydrogen peroxide, 0.1012g (1mmol) of triethylamine, 0.3067g (2mmol) of phosphorus oxychloride and 6mL of solvent anhydrous acetonitrile, and finally sleeving an oxygen balloon above a reaction tube to react for 12 hours at 0 ℃; after the reaction is finished, the sample is taken to measure GC-MS, the conversion rate of a reaction substrate is more than 89%, the selectivity of the product is 90%, ether (or ethanol, ethyl acetate and the like) is added into a reaction system, white solid is obtained by filtering, washing and drying are carried out, the white solid is collected and recycled, the filtrate is separated and purified to obtain white molten solid, and the product, namely the 4, 4' -diphenylmethane diisocyanate is confirmed by nuclear magnetism.

Example 7

The reaction steps are the same as example 5, and the difference from example 2 is that the catalyst is used for the 1 st time after recovery, GC-MS analysis shows that the substrate conversion rate is more than 91%, the selectivity is about 95%, the product is obtained by separation and purification, and nuclear magnetism confirms that 4, 4' -diphenylmethane diisocyanate, and the yield is 91%.

Example 8

The reaction steps are the same as example 5, and the difference from example 2 is that the catalyst is used for the 2 nd time after being recovered, GC-MS analysis shows that the substrate conversion rate is more than 89%, the selectivity is about 95%, the product is obtained by separation and purification, and the nuclear magnetism confirms that the yield is 89% for 4, 4' -diphenylmethane diisocyanate.

Example 9

The reaction steps are the same as example 5, and the difference from example 2 is that the catalyst is used for the 3 rd time after being recovered, GC-MS analysis shows that the substrate conversion rate is more than 88%, the selectivity is about 93%, the product is obtained by separation and purification, and the nuclear magnetism confirms that the product is 4, 4' -diphenylmethane diisocyanate, and the yield is 86%.

Example 10

The reaction steps are the same as example 5, and are different from example 2 in that the catalyst is used for the 4 th time after recovery, GC-MS analysis shows that the substrate conversion rate is more than 87%, the selectivity is about 90%, the product is obtained by separation and purification, and the nuclear magnetism confirms that the yield is 84% for 4, 4' -diphenylmethane diisocyanate.

Example 11

The reaction steps are the same as example 5, and different from example 2 in that the catalyst is used for the 5 th time after being recovered, GC-MS analysis shows that the substrate conversion rate is more than 85%, the selectivity is about 89%, the product is obtained by separation and purification, and the nuclear magnetism confirms that the product is 4, 4' -diphenylmethane diisocyanate, and the yield is 83%.

All of the above-described first embodiments are not intended to suggest any alternative form of implementing the new and/or novel methods. Those skilled in the art will take advantage of this important information, and the foregoing will be modified to achieve similar performance. However, all modifications or adaptations based on the present invention belong to the rights reserved for the present invention.

The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.