Organic amine catalyst as well as preparation method and application thereof

Abstract

The invention relates to an organic amine catalyst as well as a preparation method and application thereof. The structural general formula of the organic amine catalyst is shown in the specification.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polyurethane, and particularly relates to a kind of organic amine catalyst and its preparation method and application. BACKGROUND

[0002] Polyurethane foam, as a key material in the fields of thermal insulation, sound insulation, shock absorption, etc., is widely used in the construction, cold chain, automobile and other industries. In the traditional polyurethane foaming system, the formulation using high GWP (Global Warming Potential) blowing agents such as HFC-245fa, HFC-134a, etc. is gradually restricted by environmental regulations. In recent years, HFO blowing agents with low GWP and zero ozone depletion potential, such as HFO-1233zd (E) and HFO-1336mzz (Z), have rapidly become the mainstream alternative solution.

[0003] However, the carbon-carbon double bond in the HFO molecule has strong reactivity with the active fluorine group, and it is easy to undergo addition reaction, defluorination reaction or cyclization reaction with commonly used tertiary amine catalysts (such as DABCO, BDMA, PMDETA, TEA, etc.) in actual foaming operation, resulting in catalyst deactivation, foam collapse, foaming delay, and microcellular structure disorder. Literature reports show that the side reactions of the catalyst with HFO not only cause performance problems, but also may form fluorine-containing by-products that corrode equipment, affecting the stable operation of the device.

[0004] Existing research attempts to develop catalyst systems with higher stability to HFO, such as: introducing large steric alkyl or cyclic groups at the N position to slow down the attack of the double bond; constructing a macromolecular organic amine skeleton to dilute the local electron density; adding auxiliary stabilizers (such as phenols, antioxidants) to block the side reaction chain, etc.

[0005] US20150315329A1 discloses a class of N-substituted piperidine derivatives, such as N,N-dimethyl-N-isopropylpiperidine, used as catalysts for polyurethane foam. Its basicity is lower than that of traditional tertiary amines, which can partially improve the stability in HFO system. The cyclic piperidine structure is adopted, and a large steric alkyl group is introduced at the N position to reduce the reaction probability with HFO, but the catalytic activity is significantly reduced, and it needs to be used with other catalysts; the performance is unstable in high water amount system.

[0006] WO2020134567A1 discloses a macromolecular organic amine catalyst based on a polyether skeleton, with tertiary amine structures introduced at both ends of the molecule to improve thermal stability and chemical inertness. The active site is covered with a macromolecular segment to increase steric hindrance and prevent reaction with HFO. The catalytic efficiency depends on the control of molecular weight; there may be compatibility problems with polyol systems, and the dispersion is poor.

[0007] CN109347892A by adding conventional catalysts with antioxidants, metal complexes, etc. to inhibit its side reaction with HFO. The catalyst structure is not directly improved, but the external stabilizer is used to prevent catalyst deactivation. The system is complex, the components are many, the window is narrow, and there are risks of stabilizer migration and inhibition of catalytic activity.

[0008] WO2020032457A1 develops a class of organic amines with strong electron-withdrawing groups (such as amides, fluorinated alkyl groups) to enhance the electron affinity of the catalyst center, thereby reducing the nucleophilic addition reaction of HFO. The introduction of polar electron-regulating groups near the basic core slows down the side reaction. But the catalytic activity and foam reaction speed are greatly affected, and it is difficult to control the mold opening time.

[0009] Although the above patents propose various design strategies, there are still the following common problems: chemical stability and catalytic efficiency are difficult to balance; the synthesis route is complex or the raw material cost is high, which is not conducive to industrialization; the adaptability to specific HFO (such as 1233zd and 1336mzz) system is poor; the system compatibility and low-temperature catalytic activity still need to be improved.

[0010] Therefore, it is of great significance to develop an organic amine catalyst that balances chemical stability and catalytic activity for improving the stability and structural uniformity of polyurethane foam products. SUMMARY

[0011] The technical problem to be solved by the present application is to provide an organic amine catalyst and its preparation method and application. The catalyst has excellent chemical stability and can effectively avoid the reaction with HFO during foaming to cause catalyst deactivation and unstable foaming quality.

[0012] The present application provides an organic amine catalyst, whose general structure is ; wherein n = 0-2, preferably 1-2; R1 and R2 are each independently selected from one or more of ethyl, isopropyl, tert-butyl, and methyl isopropyl.

[0013] The present application also provides a preparation method of an organic amine catalyst, comprising the following steps:

[0014] (1) Ammoniation reaction of polyol and liquid ammonia under the action of hydrogen and fixed-bed catalyst to obtain an organic primary amine intermediate;

[0015] (2) Hydrogenation reaction of the above-mentioned organic primary amine intermediate and alkylating agent in the presence of hydrogen and heterogeneous catalyst, and the crude product is subjected to desolventization and dehydration, and the light components are obtained.

[0016] Preferably, the polyhydric alcohol in step (1) includes one or more of triethylene glycol, tetraethylene glycol; the molar ratio of the polyhydric alcohol to liquid ammonia is 1:5-10.

[0017] Preferably, the fixed-bed catalyst in step (1) is a metal catalyst

[0018] Preferably, the pressure of the amination reaction in step (1) is 5-15 MPa, more preferably 8-15 MPa, and most preferably 10-14 MPa; the temperature of the amination reaction is 150-220 o C, and more preferably 160-200 o C, and most preferably 160-180 o C.

[0019] Preferably, the alkylating agent in step (2) includes one or more of methanol, formaldehyde, acetaldehyde, and the molar ratio of the alkylating agent to the organic primary amine intermediate is 1-3:1.

[0020] Preferably, the heterogeneous catalyst in step (2) is palladium on carbon.

[0021] Preferably, the pressure of the hydrogenation reaction in step (2) is 10-15 MPa, and more preferably 10-13 MPa; the temperature of the hydrogenation reaction is 80-130 o C, and more preferably 100-120 o C.

[0022] The present application also provides a use of a class of organic amine catalysts in the preparation of polyurethane foam, and one or more of the organic amine catalysts can be used as a composition.

[0023] In some cases, the organic amine catalyst can be used in combination with commercially available catalysts, such as POLYCAT® 12, POLYCAT® 204, POLYCAT® 206, and acid-terminated catalysts, and the acids that can be used include but are not limited to formic acid, acetic acid, propionic acid, butyric acid, valeric acid, pivalic acid, hexanoic acid, 2-ethylhexyl carboxylic acid, neohexanoic acid, octanoic acid, neooctanoic acid, heptanoic acid, neoheptanoic acid, nonanoic acid, neononanoic acid, decanoic acid, neodecanoic acid, undecanoic acid, neododecanoic acid, dodecanoic acid, myristic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, benzoic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, glycolic acid, lactic acid, tartaric acid, citric acid, malic acid, and salicylic acid.

[0024] Preferably, the raw materials for preparing the polyurethane foam include the following components:

[0025] (a) Polyol resin blends, including:

[0026] i) at least one polyol;

[0027] ii) 5-80 pphp of foaming agent;

[0028] iii) 0.5-10 pphp of surfactant;

[0029] iv) 0-60 pphp of water;

[0030] v) Flame retardant of 0-50 pphp;

[0031] vi) 0-10 pphp of solubilizer;

[0032] vii) 0.05-20 pphp organic amine catalyst;

[0033] (b) At least one polyisocyanate.

[0034] The term pphp refers to the number of parts by weight per 100 parts by weight of polyol.

[0035] Preferably, the polyol comprises one or more of sucrose and / or sorbitol-initiated polyether polyols and / or aromatic polyester polyols.

[0036] Preferably, the foaming agent includes one or more of trans-1-chloro-3,3,3-trifluoropropene (HFO-1233zd(E)) and / or trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz(E)).

[0037] Preferably, the surfactant comprises a polysiloxane-polyether copolymer, more preferably one or more of Tegostab B84806, B8490, Niax L-6900 or Loca S193.

[0038] Preferably, the flame retardant comprises one or more of tris(2-chloropropyl) phosphate (TCPP), triethyl phosphate (TEP), and / or reactive phosphorus-containing polyols.

[0039] Preferably, the solubilizer includes one or more of propylene carbonate, ethylene carbonate, and butyl acetate.

[0040] Preferably, the polyisocyanate comprises polymeric MDI, having an NCO mass fraction of 30.5% to 31.8% or more.

[0041] Beneficial effects

[0042] The catalyst of this invention exhibits excellent catalytic activity and system compatibility in the production process of polyurethane foam, especially when using low-GWP environmentally friendly blowing agents, and has good application prospects. Detailed Implementation

[0043] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0044] Example 1

[0045] A 250 mL fixed-bed reactor was loaded with 200 g of 4*4 mm metal catalyst (Ni-Cu-Co-Zr). Hydrogen was introduced into the reactor at a rate of 150 mL / min using a mass flow meter, and the pressure was controlled at 13 MPa. The temperature was raised to 180 °C. Triethylene glycol (150 g / h) and liquid ammonia (136 g / h) were continuously introduced into the reactor (molar ratio 1:8) using an HPLC pump. After removing excess liquid ammonia, an organic primary amine intermediate was obtained. The organic primary amine intermediate, along with 20% excess formaldehyde and hydrogen, was passed through another fixed-bed reactor (loaded with Pd-C, catalytic concentration) at 120 °C and 13 MPa. Then, it was passed through the same reactor with acetone (15% excess). The crude product was distilled to remove solvent, water, and light components, yielding organic amine catalyst I (purity >98%) and organic amine catalyst II (purity >97.5%), with a mass ratio of 6:1.

[0046] The structural formula of organic amine catalyst I is: .

[0047] The structural formula of organic amine catalyst II is: .

[0048] Example 2

[0049] A 250 mL fixed-bed reactor was loaded with 200 g of 4*4 mm metal catalyst (Ni-Cu-Co-Zr). Hydrogen was introduced into the reactor at a rate of 120 mL / min using a mass flow meter, and the pressure was controlled at 13 MPa. The temperature was raised to 185 °C. Tetraethylene glycol (100 g / h) and liquid ammonia (70 g / h) were continuously introduced into the reactor (molar ratio 1:8) using an HPLC pump. After removing excess liquid ammonia, an organic primary amine intermediate was obtained. The organic primary amine intermediate, along with 20% excess formaldehyde and hydrogen, was passed through a fixed-bed reactor (loaded with Pd-C, catalytic concentration) at 120 °C and 13 MPa. Then, it was passed through the same reactor with acetone (15% excess). The crude product was distilled to remove solvent, water, and light components, yielding organic amine catalyst III with a purity greater than 98.2%.

[0050] The structural formula of organic amine catalyst III is: .

[0051] Example 3

[0052] A 200 g 4*4 mm metal catalyst (Ni-Cu-Co-Zr) was loaded into a 250 mL fixed-bed reactor. Hydrogen was introduced into the reactor at a rate of 150 mL / min using a mass flow meter, and the pressure was controlled at 13 MPa. The temperature was raised to 185 °C. Triethylene glycol (150 g / h) and liquid ammonia (70 g / h) were continuously introduced into the reactor (molar ratio 1:8) using an HPLC pump. After removing excess liquid ammonia, an organic primary amine intermediate was obtained. The organic primary amine intermediate was then passed through a fixed-bed reactor (loaded with Pd-C, catalytic concentration) at 120 °C and 13 MPa with excess acetaldehyde and hydrogen. The crude product was distilled to remove solvent, water, and light components, yielding organic amine catalyst IV with a purity greater than 98.6%.

[0053] The structural formula of organic amine catalyst IV is: .

[0054] Example 4

[0055] A 250 mL fixed-bed reactor was loaded with 200 g of 4*4 mm metal catalyst (Ni-Cu-Co-Zr). Hydrogen was introduced into the reactor at a rate of 120 mL / min using a mass flow meter, and the pressure was controlled at 13 MPa. The temperature was raised to 185 °C, and tetraethylene glycol (100 g / h) and liquid ammonia (70 g / h) were continuously introduced into the reactor (molar ratio 1:8) using an HPLC pump. After removing excess liquid ammonia, an organic primary amine intermediate was obtained. The organic primary amine intermediate was then passed through a fixed-bed reactor (loaded with Pd-C, catalytic concentration) at 120 °C and 13 MPa with excess acetaldehyde and hydrogen. The crude product was distilled to remove solvent, water, and light components, yielding organic amine catalyst V with a purity greater than 97.8%.

[0056] The structural formula of organic amine catalyst V is: .

[0057] Example 5

[0058]

[0059] A 200 g 4*4 mm metal catalyst (Ni-Cu-Co-Zr) was loaded into a 250 mL fixed-bed reactor. Hydrogen was introduced into the reactor at a rate of 120 mL / min using a mass flow meter, and the pressure was controlled at 13 MPa. The temperature was raised to 185 °C. Tetraethylene glycol (100 g / h) and liquid ammonia (70 g / h) were continuously introduced into the reactor (molar ratio 1:8) using an HPLC pump. After removing excess liquid ammonia, an organic primary amine intermediate was obtained. The organic primary amine intermediate was then passed through a fixed-bed reactor (loaded with Pd-C, catalytic concentration) at 120 °C and 13 MPa with an excess of 10% formaldehyde and acetaldehyde (mass ratio 2:3) and hydrogen. The crude product was distilled, dehydrated, and the light components were removed to obtain a mixture of organic amine catalysts VI and VII (mass ratio 3:1) with a total purity greater than 98%.

[0060] The structural formula of organic amine catalyst VI is: .

[0061] The structural formula of organic amine catalyst VII is: .

[0062] Example 6

[0063] The performance of organic amine catalysts I and II in polyurethane systems for spray foam with HFO blowing agent was tested. The performance and pot life stability of the organic amine catalysts were tested using the foam formulations in Table 1.

[0064] Table 1. Formula used in this embodiment

[0065]

[0066] Combination polyols: a mixture of Stepan Polyester (Stepanpol PS3152) and Jurong Ningwu New Materials Co., Ltd. polyether polyol (NJ-M330) (ratio of 1:1);

[0067] Flame retardant: Wansheng Group's phosphate ester flame retardant WSFR-TCPP;

[0068] Surfactant: Shanghai Xinrui New Materials' Loca S193 surfactant;

[0069] HFO foaming agent: Honeywell LBA;

[0070] HFO solubilizer: Shanghai Xinrui New Materials XR PM301;

[0071] Polyisocyanate: Huntsman Suprasec-5005 MDI.

[0072] After mixing the above polyol resin blend components according to the formulation, place them in a 500mL plastic beaker. Add the polyisocyanate to the beaker and mix at 4000rpm for 3 seconds. Immediately after mixing, place the beaker under sonar using a Foamat machine (FOAMATMesstechnik GmbH), and use software equipment to obtain the foam rise curve and measure the 120-second rise rate (ROR) curve. Three samples containing the same formulation were stored in three sealed aluminum bottles and heated at 50°C for four weeks. The ROR curves were monitored at week 0, week 1, week 2, and week 4, and the observations are summarized in Table 2.

[0073] Table 2. Time (in seconds) to reach 80% of maximum height in manual mixing experiments using organic amine catalysts I and II.

[0074]

[0075] Table 2 clearly shows that the organic amine catalyst loses its reactivity after 4 weeks at 50°C. However, it was found that the organic amine catalyst exhibits excellent stability within 2 weeks at 50°C. After 2 weeks at 50°C, it begins to lose its reactivity. By the fourth week, it has lost 21.5% of its original reactivity.

[0076] Example 7

[0077] The pot life study was conducted using organic amine catalyst III in the same manner as in Example 6, and the results are shown in Table 3.

[0078] Table 3. Time (in seconds) to reach 80% of maximum height in manual mixing experiments using organic amine catalyst III.

[0079]

[0080] Example 8

[0081] The pot life study was conducted using organic amine catalyst IV in the same manner as in Example 6, and the results are shown in Table 4.

[0082] Table 4. Time (in seconds) to reach 80% of maximum height in manual mixing experiments using organic amine catalyst IV.

[0083]

[0084] Example 9

[0085] The pot life study was conducted using organic amine catalyst V in the same manner as in Example 6, and the results are shown in Table 5.

[0086] Table 5. Time (in seconds) to reach 80% of maximum height in manual mixing experiments using organic amine catalyst V.

[0087]

[0088] Example 10

[0089] The pot life studies were conducted using organic amine catalysts VI and VII in the same manner as in Example 6, and the results are shown in Table 6.

[0090] Table 6. Time (in seconds) to reach 80% of maximum height in manual mixing experiments of organic amine catalysts VI and VII.

[0091]

[0092] Comparative Example 1

[0093] The standard catalyst N,N,N,N”,N”-pentamethyldiethylenetriamine (PMDETA) used in the polyurethane system with rigid sprayed foam was subjected to a pot life study in the same manner as in Example 6, and the results are shown in Table 7.

[0094] Table 7. Time (in seconds) to reach 80% of maximum height in manual mixing experiments conducted by PMDETA.

[0095]

Claims

1. A class of organic amine catalysts, characterized in that, Its general structural formula is 2. A method for preparing a class of organic amine catalysts, characterized in that, Includes the following steps: (1) Polyol and liquid ammonia are subjected to ammoniation reaction under the action of hydrogen and fixed bed catalyst to obtain organic primary amine intermediate; (2) The above-mentioned organic primary amine intermediate and alkylating agent are subjected to hydrogenation reaction in the presence of hydrogen and heterogeneous catalyst. The crude product is desolvated and dehydrated, and the light components are removed to obtain the organic amine catalyst.

3. The preparation method according to claim 2, characterized in that, The polyol in step (1) includes one or more of triethylene glycol and tetraethylene glycol; the molar ratio of the polyol to liquid ammonia is 1:5-10.

4. The preparation method according to claim 2, characterized in that, The fixed-bed catalyst in step (1) is a metal catalyst.

5. The preparation method according to claim 2, characterized in that, The ammoniation reaction pressure in step (1) is 5-15 MPa, and the ammoniation reaction temperature is 150-220°C. o C.

6. The preparation method according to claim 2, characterized in that, The alkylating agent in step (2) includes one or more of methanol, formaldehyde, and acetaldehyde, and the molar ratio of the alkylating agent to the organic primary amine intermediate is 1-3:

1.

7. The preparation method according to claim 2, characterized in that, The heterogeneous catalyst in step (2) is palladium on carbon.

8. The preparation method according to claim 2, characterized in that, The hydrogenation reaction pressure in step (2) is 10-15 MPa, and the hydrogenation reaction temperature is 80-130°C. o C.

9. The application of an organic amine catalyst according to claim 1 in the preparation of polyurethane foam.

10. The application according to claim 9, characterized in that: The raw materials for preparing polyurethane foam include the following components: (a) Polyol resin blends, including: i) at least one polyol; ii) 5-80 pphp of foaming agent; iii) 0.5-10 pphp of surfactant; iv) 0-60 pphp of water; v) Flame retardant of 0-50 pphp; vi) 0-10 pphp of solubilizer; vii) 0.05-20 pphp organic amine catalyst; (b) At least one polyisocyanate.

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