REDUCTIVE AMINATION CATALYST FOR PREPARATION OF POLYETHER AMINE AND ITS PREPARATION METHOD

Abstract

Provided are a reductive amination catalyst for preparation of polyether amine and its preparation method. According to the reductive amination catalyst, a reductive amination reaction includes: enabling polyether polyols to undergo a hydroamination reaction in presence of the reductive amination catalyst to prepare polyether amine. The reductive amination catalyst includes an MgAl.sub.2O.sub.4 carrier, Ni, Pd and Cu active components loaded thereon. -Al.sub.2O.sub.3 modified by MgO is used as the carrier for the amination catalyst, and the modified MgAl.sub.2O.sub.4 carrier has characteristics of high temperature resistance, high mechanical strength and low surface acidity, which can better adapt to the high temperature and high pressure reaction conditions required for low-carbon alkane dehydrogenation. In presence of the catalyst, the temperature of a reaction system is low, and the activity or selectivity of the catalyst is suitable for oligomeric oxypropylene ether. The Raw materials and catalyst facilitate the preparation of low-color-value polyether amine.

Claims

1. A reductive amination catalyst for preparation of polyether amine, wherein the reductive amination catalyst comprises an MgAl.sub.2O.sub.4 carrier, and Ni, Pd and Cu active components loaded thereon.

2. The reductive amination catalyst according to claim 1, wherein the reductive amination catalyst is prepared from the following components by weight percent: 2-15 wt % of Ni, 0.1-2 wt % of Pd, 0.05-1 wt % of Cu, and 84-95 wt % of MgAl.sub.2O.sub.4.

3. The reductive amination catalyst according to claim 2, wherein the reductive amination catalyst is prepared from the following components by weight percent: 5-10 wt % of Ni, 0.5-1.5 wt % of Pd, 0.1-0.5 wt % of Cu, and 89-93 wt % of MgAl.sub.2O.sub.4.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

Example 1

[0028] This example provides a method for preparing polyether amine by amination of polyether polyols, including the following steps:

[0029] The polyether polyols were subjected to a hydroamination reaction in presence of a reductive amination catalyst to prepare polyether amine, and a continuous fixed bed process was used for evaluation.

[0030] The specific method was as follows: the catalyst was reduced at 200 C. for 15 h in a hydrogen stream (under normal pressure) before use; the interior of a reactor was naturally cooled to 150 C. and pressurized to 17.0 MPa; after the system was stabilized, a liquid stream with a molar ratio of NH3/PPG230=15 was pumped into the reactor through a pump, and hydrogen was introduced in an amount of 1 time of the molar amount of PPG-230; and after a period of reaction, a polyether amine product was obtained by filtration and vacuum distillation.

[0031] The reductive amination catalyst includes an MgAl.sub.2O.sub.4 carrier, and Ni, Pd and Cu active components loaded thereon.

Example 2

[0032] This example provides the preparation method of the reductive amination catalyst used in Example 1:

[0033] Based on the weight of the catalyst, the content of Ni was 8 wt %, the content of Pd was 1.0 wt %, and the content of Cu was 0.25 wt %. The preparation method of the catalyst was as follows: sufficient aqueous solutions of Ni(NO.sub.3).sub.3.Math.6H.sub.2O, Pd(NO.sub.3).sub.2.Math.2H.sub.2O, and Cu(NO.sub.3).sub.2.Math.3H.sub.2O were added into 100 g of an MgAl.sub.2O.sub.4 carrier, the obtained mixture was dried at 110 C. for 6 h after adsorption equilibrium, and then calcination was carried out for 11 h at 450 C. in the air to obtain a product recorded as a catalyst CAT-1.

[0034] The preparation method of a catalyst with Al.sub.2O.sub.3 as a carrier was as follows: based on the weight of the catalyst, the content of Ni was 8 wt %, the content of Pd was 1.0 wt %, and the content of Cu was 0.25 wt %. The preparation method of the catalyst was as follows: sufficient aqueous solutions of Ni(NO.sub.3).sub.3.Math.6H.sub.2O, Pd(NO.sub.3).sub.2.Math.2H.sub.2O, and Cu(NO.sub.3).sub.2.Math.3H.sub.2O were added into 100 g of an Al.sub.2O.sub.3 carrier, the obtained mixture was dried at 110 C. for 6 h after adsorption equilibrium, and then calcination was carried out for 11 h at 450 C. in the air; copper nitrate, nickel nitrate and palladium nitrate were added into deionized water according to a formula ratio to prepare a metal salt solution; the Al.sub.2O.sub.3 carrier was immersed into the metal salt solution; the obtained mixture was heated and stirred at 60-80 C., and then dried after reaching a full adsorption equilibrium; calcination was carried out in a muffle furnace at 360 C. for 4 h; and after cooling, the product was reduced in a hydrogen atmosphere to obtain the catalyst recorded as a catalyst CAT-2.

[0035] When CAT-1 and CAT-2 are adopted, the reaction conversion rates, average amination rates (obtained after CAT-2 is used for 24 times and CAT-1 is used for 45 times), primary amine selectivity, average destruction rates and other properties are shown in Table 1. The reaction conversion rates, average amination rates, primary amine selectivity and average destruction rates involved in Table 1 are all average values. Taking the reaction conversion rate as an example, the reaction conversion rate was calculated by dividing the sum of the reaction conversion rates of all tests by the number of the tests, where CAT-2 was used for 24 times and CAT-1 was used for 45 times. After chemical analysis, the PtCo color number of a polyether amine product is 3 to 5. The catalyst was continuously operated for 2000 h, and the sampling analysis showed that the key indicators such as color, amination rate and primary amine selectivity did not change. Conversion rate %=(1polyether amount/total polyether amount)100%, selectivity %=(primary amine value/total amine value)100%, amination rate=(total amine value/polyether hydroxyl value)100%. The end of test life is based on the amination rate lower than 92% for three consecutive times, and catalyst lifetime n (times)=test times3. Catalyst destruction rate-(catalyst reduction amount/catalyst input amount)100%.

[0036] A high-pressure reactor was used as a reaction vessel to carry out a reductive amination reaction with polyether polyols, liquid ammonia and hydrogen as starting materials. The performance of the catalyst was preliminarily evaluated under the following conditions: the adding amount of the catalyst was 60 g, the adding amount of the polyether polyols was 200 g, the adding amount of the liquid ammonia was 150 g, the initial hydrogen pressure was 2.5 Mpa, the reaction temperature was 165 C., and the holding time was 5 h.

TABLE-US-00002 TABLE 1 Comparison of performance of catalysts loaded on different carriers amine Average Average Average Type of Service amination Primary amine destruction catalyst life (times) rate % selectivity % rate % CAT-2 24 97.7 97.5 0.26 CAT-1 45 98.9 99.0 0.11

[0037] Conclusion: The catalyst prepared by the MgAl.sub.2O.sub.4 carrier used in the present application is longer in service life, higher in average amination rate and primary amine selectivity, and lower in destruction rate compared with the catalyst using alumina as the carrier, which indicates that the catalyst prepared with the MgAl.sub.2O.sub.4 carrier is less prone to damage in a system and thus has a longer service life, and its selectivity and activity are better than that prepared with the alumina as the carrier.

Example 3

[0038] This example provides the preparation method of the reductive amination catalyst used in Example 1, which includes the following steps: [0039] S11, a certain amount of spherical -Al.sub.2O.sub.3 and magnesium oxide particles were added into a mortar and then mixed evenly, and the obtained mixture was ground and screened to obtain a mixture of 100-200 meshes; [0040] S12, the mixture was transferred into a crucible and dried at 100 C. for 20 h, and then calcination was carried out at 1000-1100 C. for 20 h to obtain white powder; [0041] S13, after cooling, the produced was processed for molding to obtain a granular MgAl.sub.2O.sub.4 spherical carrier with a radius of 3-5 mm; [0042] S14, copper nitrate, nickel nitrate and palladium nitrate were added into deionized water according to a formula ratio to prepare a metal salt solution; [0043] S15, the carrier obtained in S13 was immersed into the metal salt solution obtained in S14, and a small amount of hydrochloric acid and monoethanolamine were added at the same time; the obtained mixture was heated and stirred, and then dried after reaching a full adsorption equilibrium; calcination was carried out in a muffle furnace at 360 C. for 4 h; and [0044] S16, after cooling, the product was reduced in a hydrogen atmosphere to obtain the catalyst.

[0045] The foregoing embodiments are only preferred embodiments of the present disclosure, and are not intended to limit the scope of protection of the present disclosure. Any non-substantive changes and substitutions made by those skilled in the art on the basis of the present disclosure shall fall within the scope of protection claimed by the present disclosure.