Method for preparing 1,3-propanediol by hydrogenolysis of glycerol and its reaction system

Abstract

The present disclosure provides a method for preparing 1,3-propanediol by hydrolysis hydrogenolysis of glycerol and its corresponding reaction system, wherein, this method is to produce 1,3-propanediol through contact and reaction between hydrogen and glycerol under the catalysis of a noble metal/solid acid catalyst; wherein an auxiliary agent is contained in the liquid phase of the reaction system, and the content of the auxiliary agent in the liquid phase is 10 ppm or more.

Claims

1. A method for preparing 1,3-propanediol by hydrogenolysis of glycerol, comprising: contacting and reacting hydrogen and glycerol in a reaction system under a catalysis of a noble metal/solid acid catalyst; wherein an auxiliary agent is contained in a liquid phase of the reaction system; wherein the auxiliary agent is selected from an alkali metal phosphate; and wherein the auxiliary agent in the liquid phase is present in an amount of 10 ppm or more.

2. The method of claim 1, wherein the alkali metal phosphate is selected from sodium phosphate, potassium phosphate, rubidium phosphate, cesium phosphate, lithium phosphate, and lithium dihydrogen phosphate, or a combination thereof.

3. The method of claim 2, wherein, the alkali metal phosphate is selected from rubidium phosphate, cesium phosphate, lithium phosphate, and lithium dihydrogen phosphate, or a combination thereof.

4. The method of claim 1, wherein the auxiliary agent in the liquid phase of the reaction system is present in an amount from 50 ppm to 400 ppm.

5. The method of claim 4, wherein the auxiliary agent in the liquid phase of the reaction system is present in an amount from 80 ppm to 300 ppm.

6. The method of claim 1, further comprising: wherein after a continuous contact and reaction between hydrogen and glycerol under the catalysis of the noble metal/solid acid catalyst in a fixed-bed reactor, continuously discharging a mixture formed of 1,3-propanediol, by-product, unreacted glycerol and solvent from an outlet of the fixed-bed reactor; wherein an amount of the auxiliary agent added to a feed of glycerol or solvent to the fixed-bed reactor is controlled such that the auxiliary agent contained in the mixture which is discharged from the outlet of the fixed-bed reactor is present in an amount maintained at 10 ppm or more.

7. The method of claim 6, wherein the amount of the auxiliary agent added to the feed of glycerol or solvent is controlled such that the auxiliary agent contained in the mixture which is discharged from the outlet of the fixed-bed reactor is present in an amount maintained from 50 ppm to 400 ppm.

8. The method of claim 7, wherein the amount of the auxiliary agent added to the feed of glycerol or solvent is controlled such that the auxiliary agent contained in the mixture which is discharged from the outlet of the fixed-bed reactor is present in an amount maintained from 80 ppm to 300 ppm.

9. The method of claim 1, wherein the noble metal/solid acid catalyst comprises a noble metal selected from one or a combination of platinum, palladium, rhodium, iridium, and ruthenium and a solid acid selected from one or a combination of ZrO.sub.2, WO.sub.3, MoO.sub.3, Al.sub.2O.sub.3, TiO.sub.2, and SiO.sub.2.

10. The method of claim 9, wherein the noble metal in the noble metal/solid acid catalyst is present in an amount of 0.5-3% by weight, and the rest is solid acid.

11. The method of claim 9, wherein the noble metal/solid acid catalyst is PtWO.sub.3ZrO.sub.2 or PtWO.sub.3Al.sub.2O.sub.3.

12. The method of claim 1, wherein the reaction temperature is 130-190 C. and the reaction pressure is 1-25 MPa.

13. The method of claim 1, further comprising a solvent in the reaction system selected from water, n-propanol, isopropanol, ethanol, dimethyl sulfoxide, or a combination thereof.

14. The method of claim 13, wherein the solvent in the reaction system includes water.

15. The method of claim 14, wherein the glycerol and water are added in the form of an aqueous glycerol solution, wherein the aqueous glycerol solution has a mass concentration of 20-90% by weight.

16. The method of claim 1, wherein hydrogen to glycerol that is fed into the reaction system is present in a molar ratio from 1:1 to 20:1.

17. A reaction system for preparing 1,3-propanediol by hydrogenolysis of glycerol as used in the method of claim 1, wherein, the reaction system comprises hydrogen, glycerol, a noble metal/solid acid catalyst, and an auxiliary agent wherein the auxiliary agent is selected from an alkali metal phosphate; and wherein the content of the auxiliary agent in a liquid phase of the reaction system is 10 ppm or more.

Description

DETAILED DESCRIPTION

(1) A number of embodiments of the disclosure have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the present disclosure. Accordingly, other embodiments are within the scope of the following claims.

(2) By way of non-limiting illustration, examples of certain embodiments of the present disclosure are given below.

(3) The technical solutions of the invention shall be now described in detail as follows in order to have a clearer understanding of the technical features, purposes and beneficial effects of the invention, but it should not be understood as limiting of the implementable range of the invention.

Example 1

(4) The present example provided a method for preparing 1,3-propanediol by hydrogenolysis of glycerol (the auxiliary agent was added into the aqueous glycerol solution), in which the catalyst as used was PtWO.sub.3ZrO.sub.2 (the content of Pt was 2.0% by weight; the content of WO.sub.3 was 30% by weight, and rest was ZrO.sub.2) prepared by the conventional method. This method included the following steps:

(5) (1) The catalyst was placed at a position which is 30 cm from the bottom of the reactor (a tube typed fixed-bed reactor has a diameter of 1 cm and a length of 1 m), the loaded volume of catalyst is 5 mL, wherein the particle of the catalyst is in a form of sphere with a particle size of 0.5-1.0 mm, and the rest was filled with inert alumina ball;

(6) (2) Hydrogen was continuously fed into the catalyst at 250 C. for 1 hour to activate the catalyst;

(7) (3) The aqueous glycerol solution was injected into the reactor with the rate of 0.3 h.sup.1 (this solution contained glycerol with the mass content of 60% by weight and included the auxiliary agent), and meanwhile hydrogen was injected into the reactor with a rate of 150 ml/min; the ratio of hydrogen to glycerol was 2000; the reaction conditions were as follows: reaction temperature was 150 C. and reaction pressure was 6 MPa; the reaction was carried out for 3000 hours. During the reaction, samples were taken out for analysis by chromatography. The analytic results are shown in Table 1.

(8) TABLE-US-00001 TABLE 1 test results of catalyst stability by adding different auxiliary agents into the liquid phase the added reaction for 48 hours reaction for 100 hours reaction for 300 hours reaction for 1000 hours reaction for 3000 hours auxiliary conversion selectivity conversion selectivity conversion selectivity conversion selectivity conversion selectivity agent (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) Li.sub.3PO.sub.4 54.8 50.1 49.2 51.1 43.1 51.4 36.8 49.9 29.3 52.5 10 ppm Li.sub.3PO.sub.4 58.1 53.2 56.6 53.2 48.9 54.2 44.7 54.7 39.2 55.3 50 ppm Li.sub.3PO.sub.4 60.2 55.2 59.3 57.1 58.6 58.2 58.2 58.8 58.2 59.1 100 ppm Li.sub.3PO.sub.4 62.3 54.6 58.2 56.2 53.1 57.4 51.6 56.3 49.5 57.1 300 ppm Na.sub.3PO.sub.4 50.3 47.8 48.4 48.3 43.2 49.2 35.9 48.2 26.3 48.3 100 ppm K.sub.3PO.sub.4 53.7 49.3 49.8 50.4 47.2 51.3 39.0 52.2 24.3 51.7 100 ppm Rb.sub.3PO.sub.4 56.2 57.3 50.1 58.3 51.3 57.1 50.2 58.2 50.2 58.2 100 ppm Cs.sub.3PO.sub.4 58.2 52.1 52.1 54.1 56.8 57.1 55.6 57.2 51.2 57.7 100 ppm Cs.sub.3PO.sub.4 53.1 59.1 56.1 57.9 56.9 56.3 48.3 57.5 41.6 58.5 400 ppm

(9) Note: conversion is the conversion of glycerol; selectivity=molar number of 1,3-propanediol/molar number of converted glycerol.

(10) It can be shown from the above test data that the stability of the catalyst can be greatly improved by adding the auxiliary agent into the liquid phase.

Example 2

(11) The present example provided a method for preparing 1,3-propanediol by hydrogenolysis of glycerol (auxiliary agent Li.sub.3PO.sub.4 of 100 ppm was added into the aqueous glycerol solution; in addition, a control test was provided without the auxiliary agent). The catalysts were used in this method as follows:

(12) M1: PtWO.sub.3 Al.sub.2O.sub.3 (the content of Pt was 2.0% by weight; the content of WO.sub.3 was 34% by weight, and the rest was Al.sub.2O.sub.3);

(13) M2: IrSiO.sub.2TiO.sub.2 (the content of Ir was 2.0% by weight; the content of SiO.sub.2 was 35% by weight, and the rest was TiO.sub.2);

(14) M3: PbMoO.sub.3Al.sub.2O.sub.3 (the content of Pb was 2.0% by weight; the content of SiO.sub.2 was 30% by weight, and the rest was Al.sub.2O.sub.3);

(15) During the reaction, the sample was taken out for analysis by chromatography. The analytic results are shown in Table 2.

(16) TABLE-US-00002 TABLE 2 Test results on stability under different systems Catalyst reaction for 48 hours reaction for 100 hours reaction for 300 hours reaction for 1000 hours reaction for 3000 hours and conversion selectivity conversion selectivity conversion selectivity conversion selectivity conversion selectivity auxiliary (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) M1/ 40.2 60.2 37.3 60.3 37.2 61.2 36.4 61.5 36.3 61.2 K.sub.3PO.sub.4 100 ppm M1 36.2 57.9 30.1 56.9 25.3 57.8 17.3 57.2 12.7 58.1 Without auxiliary agent M2/ 20.1 40.1 16.2 41.2 17.9 42.1 17.8 44.2 17.9 44.6 Cs.sub.3PO.sub.4 100 ppm M2 21.2 41.1 15.2 42.6 10.7 41.1 7.8 43.2 4.9 44.6 Without auxiliary agent M3/ 29.2 20.3 25.1 22.1 27.4 23.0 27.2 22.3 27.3 23.1 Li.sub.3PO.sub.4 100 ppm M3 29.8 19.3 20.2 20.7 16.7 21.6 11.8 23.3 7.3 20.9 Without auxiliary agent

(17) Note: conversion is the conversion of glycerol; selectivity=molar number of 1,3-propanediol/molar number of converted glycerol.

Comparative Example 1

(18) This comparative example provided two comparison experiments as follows: Comparison experiment A was carried out under the same process condition as that in example 1 except that no auxiliary agent was added into the liquid phase;

(19) Comparison experiment B was carried out under the same process condition as that in example 1 except that no auxiliary agent was added into the liquid phase and a different catalyst was used; the catalyst used in this comparison experiment was PtWO.sub.3ZrO.sub.2 modified by Li.sub.3PO.sub.4, which was produced by doping Li.sub.3PO.sub.4 during the preparation process of the catalyst in example 1; the content of each component in this catalyst was as follows: the content of Pt was 2.0% by weight, the content of WO.sub.3 was 30% by weight, the content of Li.sub.3PO.sub.4 was 1.0% by weight, and the rest was ZrO.sub.2. Test results are shown in Table 3.

(20) TABLE-US-00003 TABLE 3 Test results on stability of catalyst in comparison experiment reaction for 48 hours reaction for 100 hours reaction for 300 hours reaction for 1000 hours reaction for 3000 hours comparison conversion selectivity conversion selectivity conversion selectivity conversion selectivity conversion selectivity experiment (%) (%) (%) (%) (%) (%) (%) (%) (%) (%) A 54.2 46.2 48.3 47.3 40.1 48.1 30.2 48.3 12.2 49.1 B 56.4 49.3 47.3 50.1 38.7 50.3 30.9 50.5 14.6 50.7

(21) Note: conversion is the conversion of glycerol; selectivity=molar number of 1,3-propanediol/molar number of converted glycerol.

(22) It can be shown from the test data shown in Tables 1-3 that:

(23) (1) The catalyst still had good activity when the reaction was carried out for 3000 hours by using the process in the present solution. It can be seen that the stability of the catalyst can be significantly improved while this process can increase the conversion and the selectivity of 1,3-propanediol to certain degree.

(24) (2) Compared with the technical solution in which the auxiliary agent is only added into the reaction solution, the technical solution where both the catalyst and the reaction solution contain the auxiliary agent can reduce the decrease of the catalyst activity at initial stage, and thus a better stability can be obtained; moreover, this solution has more remarkable effect on providing the conversion and the selectivity for 1,3-propanediol.