A method for preparing isononanoic acid ester by hydroesterification of diisobutylene

Abstract

The invention discloses a method for preparing isononanoate by hydroesterification of diisobutylene. The method comprises: under the catalysis of cobalt salt and polyvinylpyridine-polydivinylbenzene or cobalt salt and polyvinylimidazole-polydivinylbenzene, diisobutylene, CO and fatty alcohol react to obtain isononanoate, wherein the polyvinylpyridine-polydivinylbenzene is obtained by polymerization of vinylpyridine monomer and divinylbenzene monomer in a molar ratio of 1:1 to 2:1, and the polyvinylimidazole-polydivinylbenzene is obtained by polymerization of vinylimidazole monomer and divinylbenzene monomer in a molar ratio of 1:1 to 2:1. Compared with the prior art, the present invention realizes the separation and reuse of cobalt salt, and still has high catalytic activity after multiple cycles.

Description

Technical Field

[0001] The invention belongs to the field of carboxylic acid ester synthesis, and particularly relates to a method for preparing isononanoic acid ester by hydroesterification of diisobutylene. Background Art

[0002] In 2001, Chen Jing et al. reported the preparation of isononanoic acid ester by the hydroesterification of diisobutylene catalyzed by dicobalt octacarbonyl / pyridine. The reaction conditions were V(methanol)=4.0ml, V(diisobutylene)=1.0ml, m(dicobalt octacarbonyl)=100mg, n(pyridine): n(cobalt)=1.0:1.0, t=140℃, P=6.0 MPa, and at t=12 h, the diisobutylene conversion rate and isononanoic acid methyl ester selectivity reached 96.7% and 85.8%, respectively (Fine Chemicals, 2001, 18(2): 109-111). However, the catalyst system was difficult to separate. Summary of the invention

[0003] The purpose of the present invention is to improve the above method to achieve the recycling of cobalt catalyst.

[0004] A method for preparing isononanoic acid ester by hydroesterification of diisobutylene, comprising:

[0005] Under the catalysis of cobalt salt and polyvinylpyridine-polydivinylbenzene or cobalt salt and polyvinylimidazole-polydivinylbenzene, diisobutylene, CO and fatty alcohol react to obtain isononanoic acid ester, wherein the polyvinylpyridine-polydivinylbenzene is obtained by polymerizing vinylpyridine monomer and divinylbenzene monomer in a molar ratio of 1:1 to 2:1, and the polyvinylimidazole-polydivinylbenzene is obtained by polymerizing vinylimidazole monomer and divinylbenzene monomer in a molar ratio of 1:1 to 2:1.

[0006] Preferably, the cobalt salt is Co2(CO)8 or Co(acac)3.

[0007] Preferably, the amount of the cobalt salt is 2 wt.% to 6 wt.% of the total feed amount, more preferably 4 wt.% to 6 wt.%.

[0008] Preferably, the amount of polyvinylpyridine-polydivinylbenzene or polyvinylimidazole-polydivinylbenzene is 2wt.%~10wt.% of the total feed amount.

[0009] The total feed amount is the total amount of cobalt salt, polyvinylpyridine-polydivinylbenzene or polyvinylimidazole-polydivinylbenzene, diisobutylene and fatty alcohol.

[0010] Preferably, the mass ratio of the cobalt salt to the polyvinylpyridine-polydivinylbenzene or polyvinylimidazole-polydivinylbenzene is 1.5:1 to 1:2.

[0011] Preferably, the CO pressure is 4-8 MPa, the reaction temperature is 120-180° C., and the reaction time is 6-16 h.

[0012] More preferably, the CO pressure is 6-8 MPa, the reaction temperature is 140-160° C., and the reaction time is 8-12 h.

[0013] Preferably, the fatty alcohol is a fatty alcohol having 1 to 4 carbon atoms.

[0014] More preferably, the fatty alcohol is methanol or ethanol.

[0015] Beneficial effects of the present invention:

[0016] 1. The catalyst system has low corrosiveness and no special requirements for equipment.

[0017] 2. The catalyst system can be recycled and reused, and after multiple cycles, it still has high catalytic activity, which reduces the catalyst cost. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described in detail below in conjunction with embodiments.

[0019] The two isomers of diisobutylene are 2,4,4-trimethylpentene-1 and 2,4,4-trimethylpentene-2. The content of 2,4,4-trimethylpentene-1 in the diisobutylene used in the present invention is 77.2%, and the content of 2,4,4-trimethylpentene-2 ​​is 22.4%. The reaction is as follows:

[0020]

[0021] Example 1

[0022] Preparation of polyvinylpyridine-polydivinylbenzene: 10.5g (0.1mol) 4-vinylpyridine, 6.5g (0.05mol) divinylbenzene, and 0.54g 2,2-azobisisobutyronitrile were added to 200mL of ethanol, stirred at 65°C under N2 protection for 48h, then cooled to room temperature and allowed to stand at room temperature for 12h. The solid powder was collected by filtration, washed three times with ethanol and ether respectively, vacuum dried for 12h, and set aside. The polymer is referred to as: VPy-DVB (2:1).

[0023] Example 2

[0024] The preparation of polyvinylpyridine-polydivinylbenzene was the same as in Example 1, except that the raw materials 4-vinylpyridine was 5.3 g, divinylbenzene was 6.5 g, and 2,2-azobisisobutyronitrile was 0.54 g. The polymer was abbreviated as VPy-DVB (1:1).

[0025] Example 3

[0026] The preparation of polyvinyl imidazole-polydivinylbenzene is the same as in Example 1. The reaction raw materials are 9.4 g N-vinylimidazole, 6.5 g divinylbenzene, and 0.51 g 2,2-azobisisobutyronitrile. The polymer is referred to as VIM-DVB (2:1).

[0027] Example 4

[0028] The preparation of polyvinyl imidazole-polydivinylbenzene was the same as in Example 1. The reaction raw materials were 4.7 g N-vinyl imidazole, 6.5 g divinylbenzene, and 0.51 g 2,2-azobisisobutyronitrile. The polymer was abbreviated as: VIM-DVB (1:1).

[0029] Example 5

[0030] In a 100mL reactor equipped with a dip tube and a filter, 2.4g of catalyst Co2(CO)8, 2.4g of VPy–DVB (2:1), 11.2g of diisobutylene, and 48g of methanol were added in sequence. The reaction was replaced with 0.2MPa of CO for 3 times, and the pressure was filled with CO to 6.0MPa. The reaction was heated to 150°C within 60min, and stirring was started. The reaction was carried out at 8.0MPa for 10h. After cooling to room temperature, the reaction liquid was pressed out of the dip tube through the filter, and the catalyst was retained in the reactor for repeated use. The reaction liquid was analyzed by gas chromatography. The conversion rate of diisobutylene was 87.6%, and the selectivity of methyl isononanoate was 93.1%.

[0031] Example 6

[0032] During the reaction of Example 6, Co2(CO)8 and the polymer VPy-DVB formed a complex in situ. After the reaction, the complex was separated by filtration and directly used in the next reaction without any post-treatment. The effect of each repeated use (reaction conditions were the same as in Example 6) is shown in Table 1:

[0033] Table 1

[0034]

[0035] The divinylbenzene unit introduced into the VPy-DVB polymer can improve the structural stability of the catalyst when it is reused.

[0036] Embodiments 7 to 15

[0037] The operation process of Examples 7 to 15 is the same as that of Example 5, and the specific reaction conditions are shown in Table 2:

[0038] Table 2

[0039]

[0040] The diisobutylene conversion and methyl isononanoate selectivity of Examples 7 to 15 are shown in Table 3:

[0041] Table 3

[0042]

[0043] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing isononanoic acid ester by hydroesterification of diisobutylene, comprising: Under the catalysis of cobalt salt and polyvinylpyridine-polydivinylbenzene or cobalt salt and polyvinylimidazole-polydivinylbenzene, diisobutylene, CO and fatty alcohol react to obtain isononanoic acid ester, wherein the polyvinylpyridine-polydivinylbenzene is obtained by polymerizing vinylpyridine monomer and divinylbenzene monomer in a molar ratio of 1:1 to 2:1, and the polyvinylimidazole-polydivinylbenzene is obtained by polymerizing vinylimidazole monomer and divinylbenzene monomer in a molar ratio of 1:1 to 2:

1.

2. The method according to claim 1, characterized in that: The cobalt salt is Co2(CO)8 or Co(acac)3.

3. The method according to claim 1, characterized in that: The amount of the cobalt salt used is 2wt.% to 6wt.% of the total feed amount.

4. The method according to claim 3, characterized in that: The amount of the cobalt salt used is 4 wt.% to 6 wt.% of the total feed amount.

5. The method according to claim 1, characterized in that: The amount of the polyvinyl pyridine-polydivinyl benzene or polyvinyl imidazole-polydivinyl benzene used is 2wt.% to 10wt.% of the total feed amount.

6. The method according to claim 1, characterized in that: The mass ratio of the cobalt salt to the polyvinyl pyridine-polydivinyl benzene or polyvinyl imidazole-polydivinyl benzene is 1.5:1 to 1:

2.

7. The method according to claim 1, characterized in that: The CO pressure is 4~8MPa, the reaction temperature is 120~180℃, and the reaction time is 6~16h.

8. The method according to claim 7, characterized in that: The CO pressure is 6~8MPa, the reaction temperature is 140~160℃, and the reaction time is 8~12h.

9. The method according to claim 1, characterized in that: The fatty alcohol is a fatty alcohol having 1 to 4 carbon atoms.

10. The method according to claim 9, characterized in that: The fatty alcohol is methanol or ethanol.

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