A method for oxidizing olefins

Abstract

The invention discloses a method for oxidizing olefins, which comprises contacting and reacting a liquid mixture containing olefins and at least one oxidizing agent with titanium-silicon molecular sieves in a reactor under oxidation reaction conditions, wherein the selectivity of the target oxidation product is reduced to Below the expected value, the reaction temperature and optionally the mass of oxidant in the liquid mixture is increased until the target oxidation product meets the expected value. The method can effectively prolong the single-pass service life of the titanium-silicon molecular sieve used as the catalyst, reduce the regeneration frequency of the catalyst, improve the production efficiency, improve the operation stability, and prolong the total service life of the catalyst.

Description

technical field

[0001] The present invention relates to a process for the oxidation of alkenes. Background technique

[0002] Epoxides are an important class of oxygen-containing organic compounds. For example, propylene oxide is an important basic organic chemical raw material, and its yield is second only to polypropylene among propylene derivatives. The largest use of propylene oxide is to produce polyether polyols for further processing to make polyurethane, and it can also be used to produce propylene glycol which is widely used. In addition, propylene oxide can also be used in the production of surfactants, oilfield demulsifiers, etc.

[0003] With the wide application of polyurethane and other materials, the demand for propylene oxide is increasing year by year. However, the current industrial production of propylene oxide still has drawbacks, especially the inability to meet the requirements of green chemistry. Therefore, there is an urgent need to develop econom...

Examples

Embodiment 1

[0082] The catalyst (volume average particle diameter is a spherical catalyst of 700 μm, the content of titanium silicon molecular sieve TS-1 in the catalyst is 80% by weight, the content of silicon oxide is 20% by weight, and the density is 0.74g / cm 3 ) is packed in a fixed-bed reactor to form a catalyst bed of equal diameter, wherein the number of the catalyst bed is 1 layer.

[0083]Propylene, hydrogen peroxide (provided in the form of 30% by weight hydrogen peroxide) as oxidant and acetone as solvent were mixed and fed from the bottom of the fixed bed reactor and flowed through the catalyst bed. Among them, the molar ratio of propylene to hydrogen peroxide is 1:0.5, the molar ratio of propylene to solvent acetone is 1:5, and the weight hourly space velocity of propylene is 1.5h -1 . The initial reaction temperature was 40° C., and the pressure in the fixed-bed reactor was controlled to 2.0 MPa during the reaction.

[0084] During the reaction process, the composition of ...

Embodiment 2

[0087] Adopt the same method as Example 1 to oxidize propylene, the difference is that during the reaction process, when condition 1 is met for the first time, the reaction temperature is increased by 0.02-2°C / day until condition 2 is met, and the reaction temperature is stopped. And keep it as the temperature after raising; When meeting condition 1 for the 2nd time, improve the quality of hydrogen peroxide in the liquid mixture with the amplitude of 0.02-5% / day (realize by increasing the concentration of hydrogen peroxide in hydrogen peroxide, Correspondingly reduce the consumption of hydrogen peroxide, to keep the mol ratio of hydrogen peroxide and propylene constant) until satisfying condition 2, stop improving the quality of hydrogen peroxide in the liquid mixture and keep as the numerical value after raising, and so on (that is, When condition 1 is met for the odd number of times, increase the reaction temperature by 0.02-2°C / day until condition 2 is met; when condition 1 ...

Embodiment 3

[0093] Adopt the same method as embodiment 2 to oxidize propylene, the difference is that the titanium-silicon molecular sieve TS-1 in the catalyst is replaced by an equal amount of hollow titanium-silicon molecular sieve (that is, the hollow titanium-silicon molecular sieve is formed, and the content of the hollow titanium-silicon molecular sieve is 80 % by weight, the content of silicon oxide is 20% by weight, and the density of the catalyst is 0.69g / cm 3 ).

[0094] The reaction was carried out for 880 hours. At the end of the reaction, the reaction temperature was 48° C., and the concentration of hydrogen peroxide in hydrogen peroxide was 57% by weight. The results of 0.5 hours and 880 hours of reaction are listed in Table 1.

technical field

[0001] The present invention relates to a process for the oxidation of alkenes. Background technique

[0002] Epoxides are an important class of oxygen-containing organic compounds. For example, propylene oxide is an important basic organic chemical raw material, and its yield is second only to polypropylene among propylene derivatives. The largest use of propylene oxide is to produce polyether polyols for further processing to make polyurethane, and it can also be used to produce propylene glycol which is widely used. In addition, propylene oxide can also be used in the production of surfactants, oilfield demulsifiers, etc.

[0003] With the wide application of polyurethane and other materials, the demand for propylene oxide is increasing year by year. However, the current industrial production of propylene oxide still has drawbacks, especially the inability to meet the requirements of green chemistry. Therefore, there is an urgent need to develop econom...

Examples

Embodiment 1

[0082] The catalyst (volume average particle diameter is a spherical catalyst of 700 μm, the content of titanium silicon molecular sieve TS-1 in the catalyst is 80% by weight, the content of silicon oxide is 20% by weight, and the density is 0.74g / cm 3 ) is packed in a fixed-bed reactor to form a catalyst bed of equal diameter, wherein the number of the catalyst bed is 1 layer.

[0083]Propylene, hydrogen peroxide (provided in the form of 30% by weight hydrogen peroxide) as oxidant and acetone as solvent were mixed and fed from the bottom of the fixed bed reactor and flowed through the catalyst bed. Among them, the molar ratio of propylene to hydrogen peroxide is 1:0.5, the molar ratio of propylene to solvent acetone is 1:5, and the weight hourly space velocity of propylene is 1.5h -1 . The initial reaction temperature was 40° C., and the pressure in the fixed-bed reactor was controlled to 2.0 MPa during the reaction.

[0084] During the reaction process, the composition of ...

Embodiment 2

[0087] Adopt the same method as Example 1 to oxidize propylene, the difference is that during the reaction process, when condition 1 is met for the first time, the reaction temperature is increased by 0.02-2°C / day until condition 2 is met, and the reaction temperature is stopped. And keep it as the temperature after raising; When meeting condition 1 for the 2nd time, improve the quality of hydrogen peroxide in the liquid mixture with the amplitude of 0.02-5% / day (realize by increasing the concentration of hydrogen peroxide in hydrogen peroxide, Correspondingly reduce the consumption of hydrogen peroxide, to keep the mol ratio of hydrogen peroxide and propylene constant) until satisfying condition 2, stop improving the quality of hydrogen peroxide in the liquid mixture and keep as the numerical value after raising, and so on (that is, When condition 1 is met for the odd number of times, increase the reaction temperature by 0.02-2°C / day until condition 2 is met; when condition 1 ...

Embodiment 3

[0093] Adopt the same method as embodiment 2 to oxidize propylene, the difference is that the titanium-silicon molecular sieve TS-1 in the catalyst is replaced by an equal amount of hollow titanium-silicon molecular sieve (that is, the hollow titanium-silicon molecular sieve is formed, and the content of the hollow titanium-silicon molecular sieve is 80 % by weight, the content of silicon oxide is 20% by weight, and the density of the catalyst is 0.69g / cm 3 ).

[0094] The reaction was carried out for 880 hours. At the end of the reaction, the reaction temperature was 48° C., and the concentration of hydrogen peroxide in hydrogen peroxide was 57% by weight. The results of 0.5 hours and 880 hours of reaction are listed in Table 1.

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