CN108047058B

CN108047058B - N, N-dimethyl-4-cyclohexylamino cyclohexylmethane and preparation method and application thereof

Info

Publication number: CN108047058B
Application number: CN201711269665.2A
Authority: CN
Inventors: 刘振国; 丁宗雷; 张聪颖; 张兵; 陈杰; 姜庆梅
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2017-12-05
Filing date: 2017-12-05
Publication date: 2021-02-02
Anticipated expiration: 2037-12-05
Also published as: CN108047058A

Abstract

The invention relates to N, N-dimethyl-4-cyclohexylamino cyclohexylmethane and a preparation method and application thereof. The method prepares N, N-dimethyl-4-cyclohexylaminocyclohexylmethane through hydrogenation and methylation of byproduct deaminated light components, formaldehyde and hydrogen in the HMDA reaction process under the action of a catalyst and at a certain temperature and pressure. The obtained N, N-dimethyl-4-cyclohexylamino cyclohexylmethane can be used as a polyurethane catalyst after being purified, the invention realizes the effective utilization of HMDA by-products, and the polyurethane foam prepared by the invention has the advantages of low odor, excellent physical properties and the like.

Description

N, N-dimethyl-4-cyclohexylamino cyclohexylmethane and preparation method and application thereof

Technical Field

The invention relates to utilization of a byproduct deamination mixture in a diaminodicyclohexylmethane production process. In particular to N, N-dimethyl-4-cyclohexylamino cyclohexylmethane prepared by taking a deamination mixture as a raw material and a preparation method and application thereof.

Background

Diaminodicyclohexylmethane (HMDA for short) is a raw material for preparing epoxy resin curing agents, polyamide and diisocyanate dicyclohexylmethane (HMDI). The catalyst is usually prepared by using diaminodiphenylmethane (MDA) as a raw material and reacting under the action of hydrogen and a hydrogenation catalyst. However, during the preparation of HMDA, deamination of the raw MDA, intermediates and products also occurs to form a series of mixtures of light deaminated components. At present, no effective utilization method for the product exists, and only an environment-friendly company which costs money and is qualified can be used for treating waste liquid. The production process is as follows:

therefore, the following mixture of four deaminated light components is produced in the process of producing HMDA:

the prior art has no method for utilizing the byproduct deamination in the production process of HMDA, and reports that N, N-dimethyl-4-cyclohexylamino cyclohexylmethane is used as a polyurethane foam catalyst have not been found. The invention distills the deamination mixture which is a byproduct in the production process of HMDA, obtains N, N-dimethyl-4-cyclohexylamino cyclohexyl methane through hydrogenation and methylation, and uses the N, N-dimethyl-4-cyclohexylamino cyclohexyl methane as a polyurethane catalyst.

On the other hand, tertiary amine catalysts are generally malodorous and offensive, and many are highly volatile due to their low molecular weight, and the tertiary amines released during foam processing can present considerable safety and toxicity problems. The release of residual amine during consumer use is undesirable. On the other hand, the amine catalyst of the premix reaction type has low catalytic efficiency and high cost, and is not suitable for the rigid foam plastic processing process.

Disclosure of Invention

The structure of the new catalyst N, N-dimethyl-4-cyclohexylamino cyclohexyl methane provided by the invention is very similar to that of N, N-dimethyl cyclohexylamine, but the molecular weight is large. The catalytic effect is similar to that of N, N-dimethylcyclohexylamine, but the saturated vapor pressure is much lower. The novel catalyst is a low-viscosity medium-activity amine catalyst and is used for refrigerator hard foam, plate material, spraying and on-site pouring of polyurethane hard foam. The catalyst has catalytic action on gel and foaming, provides balanced catalytic performance for foaming reaction and gel reaction of hard foam, has stronger catalysis on reaction (foaming reaction) of water and isocyanate, has moderate catalytic action on reaction of polyol and isocyanate, and is a strong initial catalyst for foam reaction. Besides the hard foam, the catalyst can also be used as an auxiliary catalyst for molding soft foam, semi-hard foam and the like.

The invention aims to utilize deamination light components which are byproducts in the HMDA manufacturing process, provides a method for preparing N, N-dimethyl-4-cyclohexylamino cyclohexylmethane by using a deamination mixture as a raw material, and uses the product as a catalyst for preparing polyurethane foam. The waste utilization is realized, and the problem of unpleasant odor generated in the using process of the common polyurethane foam catalyst can be effectively avoided by using the N, N-dimethyl-4-cyclohexylaminocyclohexylmethane as the polyurethane foam catalyst.

The invention adopts the following technical scheme:

n, N-dimethyl-4-cyclohexylaminocyclohexylmethane, of the formula:

the invention also provides a method for preparing the N, N-dimethyl-4-cyclohexylamino cyclohexylmethane, which comprises the following steps:

carrying out hydrogenation and methylation reaction on the deaminated light components, which are byproducts in the HMDA reaction process after rectification and purification, formaldehyde and hydrogen under the action of a catalyst to obtain an oil-water two-phase reaction solution, wherein the oil phase mainly contains N, N-dimethyl-4-cyclohexylamino-cyclohexyl methane, and the water phase mainly contains formaldehyde; the reaction liquid is subjected to phase separation (such as alkali washing), and the oil phase is rectified and purified to obtain the N, N-dimethyl-4-cyclohexylamino cyclohexyl methane.

The byproduct deamination light component in the rectified and purified HMDA reaction process comprises one or more of 4-anilinocyclohexylmethane, 4-cyclohexylamino phenylmethane and 4-cyclohexylamino cyclohexylmethane, because deamination is generated in the HMDA batch reaction, the type and content of deamination generated in each batch are different, and the deamination usually comprises 4.0-8.0% of 4-anilinocyclohexylmethane, 1.0-3.0% of 4-anilinocyclohexylmethane, 6.0-9.0% of 4-cyclohexylamino phenylmethane and 80.0-89.0% of 4-cyclohexylamino cyclohexylmethane by mass fraction.

The formaldehyde of the present invention is prepared using an aqueous solution of formaldehyde and/or a crude depolymerized aqueous solution of paraformaldehyde, for example, an aqueous solution of 10 to 40wt%, preferably about 37 wt% formaldehyde; the mol ratio of the formaldehyde to the deamination light component is 2-10: 1, preferably 2 to 4: 1.

the catalyst is selected from a supported palladium catalyst and/or a Raney catalyst, preferably a supported palladium catalyst, the supported palladium catalyst comprises palladium, an auxiliary agent and a carrier, wherein the content of the palladium is 0.1-50wt%, preferably 2-10wt%, the auxiliary agent is selected from one or more of ruthenium, rhodium, platinum, cobalt and copper, the content of the auxiliary agent is 0.02-3wt%, preferably 0.05-2wt%, the auxiliary agent is preferably ruthenium and rhodium, the content of the ruthenium is 0.5-2wt%, the content of the rhodium is 0.05-1wt%, and the carrier is selected from one or two or more of alumina, silica gel, kieselguhr, zeolite molecular sieve, activated carbon, titanium dioxide, lithium aluminate and zirconium oxide based on the total mass of the supported palladium catalyst.

Further, the reaction temperature of the hydrogenation and methylation reaction is 40-200 ℃, preferably 60-160 ℃; the reaction pressure (gauge pressure) is from 0.5 to 10MPa, preferably from 1 to 5 MPa.

The introduction pressure of hydrogen may be 0.5 to 3MPa, preferably about 1 to 2.5 MPa. The amount of the catalyst to be used may be 1 to 5% by mass, preferably 2 to 3% by mass, based on the by-produced deaminated light component.

The supported palladium catalyst can be prepared by a conventional impregnation method and comprises the following steps: the preparation method of the supported palladium catalyst comprises the following steps: dissolving a metal salt of palladium and one or more metal salts selected from ruthenium, rhodium, platinum, cobalt and copper in deionized water according to a ratio to form a uniform solution with a salt solution concentration of about 10-40 wt%; and then adding a carrier, carrying out rotary impregnation, evaporating to remove water, drying, roasting and cooling to obtain the supported palladium catalyst.

In a more specific embodiment, a metal salt of palladium and one or more metal salts selected from ruthenium, rhodium, platinum, cobalt, copper are dissolved in deionized water at 60-80 ℃ in proportions to form a homogeneous solution having a salt solution concentration of about 10-40 wt%; then adding a carrier, carrying out rotary dipping for 4-6h at the temperature of 60-80 ℃, and gradually evaporating water to dryness; baking in an oven at the temperature of 100-120 ℃ for 10-16 hours; and finally, moving the catalyst to a muffle furnace, heating the catalyst to 500-600 ℃ at the speed of 2-3 ℃/min in the air atmosphere, roasting the catalyst for 6-8 hours, and naturally cooling the catalyst to obtain the supported palladium catalyst.

The rectification and purification of the invention adopts normal pressure and reduced pressure rectification operation, preferably reduced pressure rectification. The rectification purification pressure (absolute pressure) may be from 0.1 to 2KPa, preferably from 0.5 to 1.2KPa, the number of theoretical plates of the rectification column is from 20 to 50, preferably about 30, and the reflux ratio is from 3 to 7:1, preferably about 5: 1 under the conditions of the following conditions.

The N, N-dimethyl-4-cyclohexylamino cyclohexylmethane prepared by the method is used as a catalyst for preparing polyurethane and/or polyisocyanurate foam.

The use of the invention, wherein: the N, N-dimethyl-4-cyclohexylaminocyclohexylmethane can be used alone or in combination with tertiary amine, organotin and metal salt catalysts which are commonly used for preparing polyurethane and/or polyisocyanurate foams. N, N-dimethyl-4-cyclohexylaminocyclohexylmethane is preferably used in combination with one or two or more of N, N, N '-pentamethyldiethylenetriamine, N, N, N' -pentamethyldipropylenetriamine, bis (2-dimethylaminoethyl) ether, or 1,3, 5-tris (dimethylaminopropyl) -1,3, 5-hexahydrotriazine. The catalyst or catalyst composition may be used in an amount of 1 to 15 parts per 100 parts by weight polyol (phr). The preferable using amount is 2-12 parts.

The preparation of polyurethane and/or polyisocyanurate foam is a process of reacting polymeric polyisocyanate with at least one active hydrogen-containing compound under the action of catalyst and foaming agent to prepare polyurethane and/or polyisocyanurate foam. The active hydrogen-containing compound is at least one polyether polyol, at least one polyester polyol, or any combination thereof. Examples of suitable polyols are polyalkylene ether-type and polyester-type polyols. Polyalkylene ether-type polyols include polyalkylene oxide polymers such as polyethylene oxide and polypropylene oxide polymers and copolymers, whose terminal hydroxyl groups are derived from polyol compounds including diols and triols; examples include ethylene glycol, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, 1, 6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, pentaerythritol, glycerol, diglycerol, trimethylolpropane, and similar low molecular weight polyols.

The polymeric polyisocyanate described herein is PM-200 or other similar polymethylene polyphenylisocyanate known in the art, commonly referred to as polymeric MDI or crude MDI, which is employed. Also suitable are "prepolymers" of these polyisocyanates, including partially pre-reacted mixtures of polyisocyanates with polyether or polyester polyols.

In the formulation of the present invention, other types of adjuvants commonly used in the preparation of polyurethane foam formulations may also be added: including chain extenders such as ethylene glycol, butylene glycol, diethylene glycol, and the like; crosslinking agents such as diethanolamine, diisopropanolamine, triethanolamine, tripropanolamine, and the like; blowing agents such as water, pentane, 141B, methyl formate, and the like; foam stabilizers such as siloxanes and the like.

The chemical reaction equation of the invention is as follows:

the invention takes deamination light components, hydrogen and formaldehyde as raw materials, firstly performs methylation reaction under the action of a catalyst, then performs benzene ring hydrogenation, and finally obtains N, N-dimethyl-4-cyclohexylamino cyclohexyl methane.

In the present invention, the deaminating light component has the same meaning as the deaminating mixture and is used interchangeably.

The invention has the positive effects that: compared with the traditional amine catalyst, the N, N-dimethyl-4-cyclohexylamino cyclohexylmethane has lower amine odor and less toxicity to operators, and can still achieve the catalytic effect similar to that of the traditional catalyst. And because the N, N-dimethyl-4-cyclohexylamino cyclohexylmethane mainly takes byproducts in industrial production as raw materials, the production cost is greatly reduced. In addition, the deamination mixture is subjected to catalytic technology of benzene ring hydrogenation and methylation to generate single N, N-dimethyl-4-cyclohexylamino cyclohexyl methane, and the catalyst and the process conditions thereof are one of innovations of the invention. Compared with N, N-dimethylcyclohexylamine which is the most commonly used catalyst for polyurethane foam, the foaming process has less smell and better foam flowability.

Drawings

Figure 1 is a graph of percent foam rise versus time for formulations 1 and 2.

FIG. 2 is a graph of reaction rates versus time for formulations 1 and 2.

Fig. 3 is an appearance diagram of the products of formulations 1 and 2.

Figure 4 is a graph of percent foam rise versus time for

formulations

3 and 4.

FIG. 5 is a graph of reaction rates versus time for

formulations

3 and 4.

Fig. 6 is an appearance diagram of the products of

formulations

3 and 4.

FIG. 7 is a nuclear magnetic resonance spectrum of N, N-dimethyl-4-cyclohexylaminocyclohexylmethane prepared in example 4.

Detailed Description

The invention is further illustrated by the following examples, but is not limited to the examples set forth.

The conditions for gas chromatographic analysis in the following examples were: an Agilent DB-5 chromatographic column, wherein the injection port temperature is 280 ℃, the FID detector temperature is 300 ℃, the column flow rate is 1.5ml/min, the hydrogen flow rate is 35ml/min, the air flow rate is 350ml/min, the temperature programming mode is that the temperature is kept for 1min at 60 ℃, and the temperature is increased to 280 ℃ at 20 ℃/min and kept for 10 min.

Example 1

Preparation of palladium catalyst 1:

12.52g of palladium nitrate dihydrate, 2.81g of rhodium nitrate and 1.38g of ruthenium acetate were dissolved in 100ml of deionized water, and the mixture was heated to 80 ℃ to form a uniform mixture93.5g of activated carbon (average particle size 20 μm, specific surface area 220 m) was added to the solution²(g), the pore volume is 0.35cc/g), the mixture is soaked in a water bath at the temperature of 80 ℃ in a rotating mode for 4 hours, then the water is gradually evaporated to dryness, and the mixture is dried in an oven at the temperature of 120 ℃ for 12 hours; and finally, moving the catalyst to a muffle furnace, heating the catalyst to 500 ℃ at the speed of 2 ℃/min in the air atmosphere, roasting the catalyst for 6 hours, and naturally cooling the catalyst to obtain the catalyst. The catalyst comprises the following components: 5wt% of Pd, 1wt% of Rh, 0.5 wt% of Ru and the balance of activated carbon, wherein the corresponding metal elements account for the total mass of the catalyst.

Example 2

Preparation of palladium catalyst 2:

25.04g of palladium nitrate dihydrate, 0.14g of rhodium nitrate and 2.76g of ruthenium acetate were dissolved in 100ml of deionized water, and the solution was heated to 60 ℃ to form a uniform solution, and 88.95g of alumina (average particle diameter 50 μm, specific surface area 180 m) was added²(g), the pore volume is 0.30cc/g), the mixture is immersed in a water bath at 70 ℃ for 5 hours in a rotating way, then the water content is gradually evaporated to dryness, and the mixture is dried in an oven at 100 ℃ for 16 hours; and finally, moving the catalyst to a muffle furnace, heating the catalyst to 550 ℃ at the speed of 3 ℃/min in the air atmosphere, roasting the catalyst for 8 hours, and naturally cooling the catalyst to obtain the catalyst. The catalyst comprises the following components: 10wt% of Pd, 0.05 wt% of Rh, 1wt% of Ru and the balance of alumina, wherein corresponding metal elements account for the total mass of the catalyst.

Example 3

Preparation of palladium catalyst 3:

5.01g of palladium nitrate dihydrate, 1.40g of rhodium nitrate and 5.51g of ruthenium acetate were dissolved in 100ml of deionized water, and the solution was heated to 70 ℃ to form a uniform solution, and 95.5g of silica (average particle diameter: 60 μm, specific surface area: 240 m) was added²(g), the pore volume is 0.38cc/g), the mixture is soaked in a water bath at 60 ℃ in a rotating mode for 6 hours, then the water is gradually evaporated to dryness, and the mixture is dried in an oven at 120 ℃ for 12 hours; and finally, moving the catalyst to a muffle furnace, heating the catalyst to 600 ℃ at the speed of 2 ℃/min in the air atmosphere, roasting the catalyst for 6 hours, and naturally cooling the catalyst to obtain the catalyst. The catalyst comprises the following components: pd 2wt%, Rh 0.5 wt%, Ru 2wt%, and the balance of silicon dioxide, wherein corresponding metal elements account for the total mass of the catalyst.

Example 4

Preparation of N, N-dimethyl-4-cyclohexylaminocyclohexylmethane:

5g Rh/Al was added to a 2L autoclave₂O₃The catalyst is sealed by combining the kettle under 10MPa, if the catalyst is not sealed, 500g of 4, 4' -MDA and 500g of tetrahydrofuran are added, nitrogen and hydrogen under 1MPa (gauge pressure) are respectively used for replacing three times, the pressure is supplemented to 4.5MPa (gauge pressure) by hydrogen, the temperature is increased to 190 ℃, hydrogen is continuously introduced into the reaction kettle through a hydrogen flow controller in the reaction process, the pressure in the kettle is ensured to be maintained to 8MPa (gauge pressure), and when the instantaneous flow of the hydrogen flow controller is lower than 100sccm, the introduction of the hydrogen is stopped. And when the pressure of the reaction kettle is reduced to 1bar/10min, stopping the reaction, reducing the temperature in the reaction kettle to 50 ℃, relieving the pressure, and filtering through a filter arranged in the reaction kettle to obtain the HMDA reaction solution. The HMDA reaction solution is stirred at the pressure of 10KPa, the theoretical plate number of a rectifying column of 30, the reflux ratio of 3: the deamination light component is obtained by reduced pressure distillation under 1, and comprises the following components in percentage by mass: 5.2% of 4-anilinocyclohexylmethane, 1.7% of 4-anilinophenylmethane, 7.8% of 4-cyclohexylaminophenylmethane and 85.3% of 4-cyclohexylaminocyclohexylmethane. 4g of the palladium catalyst in example 1 was charged into a 1L reactor, a methanol solvent was added to make a bottom, the reactor was sealed, and the catalyst was activated for 6 hours at a temperature of 240 ℃ and a hydrogen pressure of 5MPa by three-pass replacement with nitrogen and hydrogen, respectively. Then cooling, decompressing and replacing with nitrogen for three times, and filtering the solvent out of the reaction kettle. And then 200g of HMDA is added for deamination, nitrogen and hydrogen are sequentially used for replacing for three times, the initial hydrogen pressure is 2MPa, the stirring is started to 700 r/min, the reaction temperature is increased to 160 ℃, the hydrogen pressure is adjusted to 3MPa, the hydrogen is continuously introduced, 170g of 37% formaldehyde aqueous solution is introduced into the reaction kettle at the speed of 2g/min by using a constant flow pump, when the instantaneous flow of a flowmeter is lower than 50sccm, a hydrogen valve is closed, and the reaction is continued for half an hour and stopped. Then cooling, decompressing, replacing for three times by nitrogen, and filtering to obtain oil-water two-phase reaction liquid. 5g of commercially available analytically pure sodium hydroxide was added to the reaction mixture, stirred at 60 ℃ for 2h, phase-separated with a pear-shaped separatory funnel, and the oil phase was taken for gas chromatography analysis, whereby the content of HMDA deamination was 0.1% and the content of N, N-dimethyl-4-cyclohexylaminocyclohexylmethane was 97.8%. Then the oil phase obtained by the operation is rectified under reduced pressure, under the pressure of 1KPa,the number of theoretical plates of the rectifying column is 30, and the reflux ratio is 5: the product with the purity of 99.5 percent of N, N-dimethyl-4-cyclohexylamino cyclohexylmethane is obtained by vacuum rectification under 1. Wherein the nuclear magnetic resonance spectrogram is shown in figure 7,¹HNMR data: (CDCl)₃As solvent, TMS as internal standard), a (2.27ppm, s), b (2.95ppm, dd) pendant, b (2.58ppm, dd) equatorial, c (1.84ppm, m) equatorial, c (1.55ppm, m) equatorial, d (1.73ppm, m) equatorial, d (0.94ppm, m) equatorial, e (1.04ppm, m), f (1.22ppm, dd), g (1.02ppm, m), h (1.40ppm, m) equatorial, h (1.37ppm, m) equatorial, i (1.39ppm, m) axial, i (1.34ppm, m) equatorial, j (1.58ppm, m) axial, i (1.06ppm, m) equatorial.

Example 5

Preparation of N, N-dimethyl-4-cyclohexylaminocyclohexylmethane:

different batches of HMDA reaction liquid are mixed under the conditions that the pressure is 10KPa, the theoretical plate number of a rectifying column is 30, the reflux ratio is 3: the deamination light component is obtained by reduced pressure distillation under 1, and comprises the following components in percentage by mass: 6.3% of 4-anilinocyclohexylmethane, 2.5% of 4-anilinophenylmethane, 6.8% of 4-cyclohexylaminophenylmethane and 84.4% of 4-cyclohexylaminocyclohexylmethane. 6g of the palladium catalyst in example 1 was charged into a 1L reactor, a methanol solvent was added to the reactor to form a bottom, the reactor was sealed, the reaction vessel was replaced with nitrogen and hydrogen gas three times, and the catalyst was activated at 240 ℃ and a hydrogen pressure of 5MPa for 6 hours. Then cooling, decompressing and replacing with nitrogen for three times, and filtering the solvent out of the reaction kettle. And then 200g of HMDA is added for deamination, nitrogen and hydrogen are sequentially used for replacing for three times, the initial hydrogen pressure is 1MPa, the stirring is started to be 700 r/min, the reaction temperature is increased to 160 ℃, the hydrogen pressure is adjusted to 5MPa, the hydrogen is continuously introduced, 170g of 37% formaldehyde aqueous solution is introduced into the reaction kettle at the speed of 2g/min by using a constant flow pump, when the instantaneous flow of a flowmeter is lower than 50sccm, a hydrogen valve is closed, and the reaction is continued for half an hour to stop the reaction. Then cooling, decompressing, replacing for three times by nitrogen, and filtering to obtain oil-water two-phase reaction liquid. 5g of commercially available analytically pure sodium hydroxide was added to the reaction mixture, stirred at 60 ℃ for 2h, phase-separated with a pear-shaped separatory funnel, and the oil phase was taken for gas chromatography analysis, whereby the content of HMDA deamination was 0.2% and the content of N, N-dimethyl-4-cyclohexylaminocyclohexylmethane was 97.4%. And then carrying out reduced pressure rectification on the oil phase obtained by the operation, wherein the pressure is 1KPa, the theoretical plate number of a rectification column is 30, and the reflux ratio is 5: the product with the purity of 99.6 percent of N, N-dimethyl-4-cyclohexylamino cyclohexylmethane is obtained by vacuum rectification under 1.

Example 6

Preparing polyurethane foam:

premix compounds were prepared using the formulations listed in table 1:

table 2: experimental formulation

Experiment 1 (formulation 1): catalyst 1 from table 2 was added to the premix batch in the amounts indicated in table 1 in the proportions indicated in the table. The premixed ingredient to which the catalyst 1 was added and 155.7g of PM200 were each kept at a constant temperature of 22 ℃ for 3 hours, and then both were mixed, rapidly stirred at 3000rpm for 10 seconds, and then the rise time, the cup opening time, the stringiness time, and the tack-free time were observed.

Experiment 2 (formulation 2): the same procedure as in formulation 1 was repeated except that catalyst 1 was replaced with catalyst 2 of the present invention.

In the invention, the reactivity of isocyanate and the reaction time in the preparation process of polyurethane foam are represented by four characteristic parameters of initiation time, cup mouth time, wire drawing time, non-stick time and the like. Wherein, the starting time refers to the time from the beginning of material mixing to the foaming expansion and rapid rise of the mixture liquid, and the size of the starting time reflects the strength of the foaming capacity of the catalyst; the drawing time (also called fiber time and gel time) is the time from the mixing of materials to the beginning of drawing 3 cm of filamentous fibers out of the foam; tack-free time (also known as set time) is the time from the start of mixing of the materials to the start of tack-free on the foam surface. The stringiness time and gel time reflect the ability of the foamed gel to cure.

The results obtained are shown in Table 3:

table 3:

as can be seen from Table 3, N, N-dimethyl-4-cyclohexylaminocyclohexylmethane can achieve foaming and gelling catalytic effects similar to those of PC-8. Meanwhile, the odor of the amine volatilized during foaming of the formula 2 (using the catalyst 2) is obviously sensed in the experimental process and is much less than that of the amine volatilized during foaming of the formula 1 (using the catalyst 1).

It can be seen from fig. 1 and 2 that the foam rise heights and reaction rates of formula 1 and formula 2 are the same, and from fig. 3, the foam of formula 2 has longer foam length, more neat ends, smoother foam skin and less defects than those of formula 1. Indicating that formulation 2 has better flow.

Example 7

Preparation of polyurethane-polyisocyanurate foams

Premix compounds were prepared using the formulations listed in table 4:

table 4: formula proportion of premixed ingredients

Table 5: experimental formulation

Experiment 3 (formulation 3): catalyst 1 from table 5 was added to the premix batch in the amounts indicated in table 4 in the proportions indicated in the table. The premixed ingredient to which the catalyst 1 was added and 219.68g of PM-700 were each kept at a constant temperature of 22 ℃ for 3 hours, and then the two were mixed, rapidly stirred at 3000rpm for 7 seconds, and then the rise time, the cup opening time, the drawing time, and the tack-free time were observed.

Experiment 4 (formulation 4): the same procedure as in formulation 1 was repeated except that catalyst 1 was replaced with catalyst 2 of the present invention.

The results obtained are shown in Table 6:

table 6:

as can be seen from Table 6, N, N-dimethyl-4-cyclohexylaminocyclohexylmethane can achieve foaming and gelling catalytic effects similar to those of PC-8. Meanwhile, the odor of the amine volatilized during foaming of the formula 2 (using the catalyst 2) is obviously sensed in the experimental process and is much less than that of the amine volatilized during foaming of the formula 1 (using the catalyst 1).

It can be seen from fig. 4 that the foam rise heights for formula 3 and formula 4 are the same, but the curve for formula 4 is more gradual. As can be seen from fig. 5, the reaction rate curve for formulation 4 is more gradual. The foaming reaction rate is more balanced relative to the formula 3, so that the foam defect caused by the rate change in the later period of the foaming reaction is reduced, and the method is favorable for the processing process of the polyurethane-polyisocyanurate foam. As can be seen in fig. 6, the foam of formulation 4 has the same length as the foam of formulation 3, but the foam skin is smoother and less defective. Indicating that formulation 4 has better flow properties.

Claims

1. A process for preparing N, N-dimethyl-4-cyclohexylaminocyclohexylmethane, comprising: carrying out hydrogenation and methylation reaction on the deaminated light components, which are byproducts in the reaction process of the rectified and purified diaminodicyclohexylmethane, formaldehyde and hydrogen under the action of a catalyst to obtain an oil-water two-phase reaction solution, wherein the oil phase mainly contains N, N-dimethyl-4-cyclohexylcyclohexylmethyl methane, and the water phase mainly contains formaldehyde; and (3) phase separation is carried out on the reaction liquid, rectification and purification are carried out on the oil phase to obtain the N, N-dimethyl-4-cyclohexylamino-cyclohexylmethane, wherein the catalyst is selected from a supported palladium catalyst, and the deamination light component comprises one or more of 4-anilino-cyclohexylmethane, 4-anilino-phenylmethane, 4-cyclohexylamino-phenylmethane and 4-cyclohexylamino-cyclohexylmethane.

2. The method of claim 1, wherein the formaldehyde is a formaldehyde aqueous solution and/or a crude depolymerization aqueous solution of paraformaldehyde, and the molar ratio of formaldehyde to deaminated light components is 2-10: 1.

3. the method of claim 1, wherein the formaldehyde is 10-40wt% formaldehyde water solution, and the molar ratio of the formaldehyde to the deaminated light component is 2-4: 1.

4. the method according to any one of claims 1 to 3, wherein the catalyst is a supported palladium-based catalyst comprising palladium, an auxiliary agent and a carrier, wherein the palladium content is 0.1 to 50wt%, the auxiliary agent is one or more selected from ruthenium, rhodium, platinum, cobalt and copper, the auxiliary agent content is 0.02 to 3wt%, and the carrier is one or more selected from alumina, silica gel, diatomaceous earth, zeolite molecular sieve, activated carbon, titania, lithium aluminate and zirconia, calculated on the total mass of the supported palladium-based catalyst.

5. The process according to any one of claims 1 to 3, wherein the catalyst is a supported palladium-based catalyst comprising palladium, an auxiliary and a carrier, wherein the palladium content is 2 to 10wt% and the auxiliary content is 0.05 to 2wt%, based on the total mass of the supported palladium-based catalyst.

6. A process according to any one of claims 1 to 3, wherein the promoter is ruthenium and rhodium, wherein the ruthenium content is from 0.5 to 2wt% and the rhodium content is from 0.05 to 1wt%, based on the total mass of the supported palladium-based catalyst.

7. The process according to any one of claims 1 to 3, wherein the reaction temperature of the hydrogenation and methylation reactions is 40 to 200 ℃; the reaction pressure is 0.5-10 MPa.

8. The process according to any one of claims 1 to 3, wherein the reaction temperature of the hydrogenation and methylation reactions is 60 to 160 ℃; the reaction pressure is 1-5 MPa.

9. The method of claim 4, wherein the step of preparing the supported palladium-based catalyst comprises: according to the proportion, metal salt of palladium and one or more metal salts selected from ruthenium, rhodium, platinum, cobalt and copper are dissolved in deionized water to form a uniform solution with the concentration of salt solution of 10-40 wt%; and then adding a carrier, carrying out rotary impregnation, evaporating to remove water, drying, roasting and cooling to obtain the supported palladium catalyst.

10. The method according to any one of claims 1 to 3, wherein the pressure for rectification purification is 0.1 to 2KPa, the number of theoretical plates of the rectification column is 20 to 50, and the reflux ratio is 3 to 7: 1.

11. The method according to any one of claims 1 to 3, wherein the pressure for rectification purification is 0.5 to 1.2KPa, the number of theoretical plates of the rectification column is 30, and the reflux ratio is 5: 1.

12. the process according to any one of claims 1 to 3, wherein the introduction pressure of hydrogen is from 0.5 to 3 MPa; the dosage of the catalyst is 1-5wt% relative to the byproduct deamination light component.

13. The process according to any one of claims 1 to 3, wherein the introduction pressure of hydrogen is from 1 to 2.5 MPa; the dosage of the catalyst is 2-3wt% relative to the byproduct deamination light component.

14. The method of any one of claims 1 to 3, wherein the deaminated light fraction comprises 4.0-8.0% by weight of 4-anilinocyclohexylmethane, 1.0-3.0% by weight of 4-anilinocyclohexylmethane, 6.0-9.0% by weight of 4-cyclohexylaminobenzylmethane, and 80.0-89.0% by weight of 4-cyclohexylaminocyclohexylmethane, based on the total weight of the deaminated light fraction.