阅读说明：本技术 一种利用溶剂调控不饱和醛酮的光催化还原反应选择性的方法 (Method for regulating and controlling selectivity of photocatalytic reduction reaction of unsaturated aldehyde ketone by using solvent ) 是由 赵进才 商锦婷 马万红 陈春城 籍宏伟 盛桦 于 2019-03-25 设计创作，主要内容包括：本发明属于光催化还原合成技术领域,具体涉及一种利用溶剂调控不饱和醛酮的光催化还原反应选择性的方法,所述方法包括如下步骤：将光催化剂、不饱和醛酮、溶剂加入到反应容器中,其中,所述溶剂包括醇,在无氧条件下,用光源照射反应容器进行反应,通过调节反应溶剂中醇的比例和/或种类,得到选择性不同的还原产物。所述方法操作简单、选择性好、产率高,选择性最高可达100％,产率最高可达100％。(The invention belongs to the technical field of photocatalytic reduction synthesis, and particularly relates to a method for regulating and controlling selectivity of photocatalytic reduction reaction of unsaturated aldehyde ketone by using a solvent, which comprises the following steps: adding a photocatalyst, unsaturated aldehyde ketone and a solvent into a reaction container, wherein the solvent comprises alcohol, irradiating the reaction container with a light source to perform reaction under the oxygen-free condition, and adjusting the proportion and/or the type of the alcohol in the reaction solvent to obtain reduction products with different selectivity. The method has the advantages of simple operation, good selectivity and high yield, wherein the selectivity can reach 100% at most, and the yield can reach 100% at most.)

1. A method for regulating and controlling selectivity of photocatalytic reduction reaction of unsaturated aldehyde and ketone by using a solvent is characterized by comprising the following steps: adding a photocatalyst, unsaturated aldehyde ketone and a solvent into a reaction vessel, wherein the solvent comprises alcohol, irradiating the reaction vessel with a light source to perform reaction under the oxygen-free condition, and obtaining reduction products with different selectivities by adjusting the proportion and/or the type of the alcohol in the solvent.

2. The process according to claim 1, characterized in that the solvent is an alcohol or a mixture of an alcohol and an inert organic solvent; the ratio of the alcohol to the inert organic solvent in the mixture is (1-10) to (1-10).

3. The process according to claim 1 or 2, wherein the alcohol is C_1-6One or more alkyl alcohol compounds.

4. The method of claim 3, wherein the alcohol is C_1-4One or more alkyl alcohol compounds.

5. The method of any one of claims 1 to 4, wherein the photocatalyst is titanium dioxide;

the unsaturated aldehyde ketone is C conjugated with C ═ O_6-24Aliphatic or aromatic aldehyde ketones.

6. The method according to any one of claims 1 to 5, wherein the concentration of the photocatalyst is 0.1 to 5g/L, and the concentration of the unsaturated aldehyde ketone is 0.01 to 5 mmol/L.

7. The process according to any one of claims 1 to 6, wherein the reactor is a transparent reactor.

8. The process of any one of claims 1 to 7, wherein the oxygen-free condition is achieved by bubbling an inert gas into the reaction vessel, the inert gas generating a pressure in the reaction vessel of 0.02MPa to 0.1 MPa;

the inert gas is one or more of nitrogen, helium and argon.

9. The method according to any one of claims 1 to 8, wherein the light source is ultraviolet or visible light having a wavelength of 360 to 720nm, and the irradiation is performed under stirring;

the light source is provided by a xenon lamp, and the power of the xenon lamp is 300W;

the irradiation time of the light source is 10-120 min;

the reaction temperature is 10-40 ℃.

10. The method as claimed in any one of claims 1 to 9, wherein the selectivity of the photocatalytic reduction reaction of the unsaturated aldehyde ketone is 45% or more and the yield is 64% or more under the regulation of the method.

Technical Field

The invention belongs to the technical field of photocatalytic reduction synthesis, and particularly relates to a method for regulating and controlling selectivity of photocatalytic reduction reaction of unsaturated aldehyde ketone by using a solvent.

Background

Industrially, unsaturated alcohol compounds are often used for flavors, fragrances, pharmaceutical intermediates, and the like, and are conventionally produced by selective reduction of unsaturated aldehyde ketones, but in practice, a C ═ C double bond is thermodynamically more easily reduced than a C ═ O double bond. For the selective reduction, the usual means is to support the synthesis catalyst with noble metal, and to use H under heating and pressurizing conditions₂As a hydrogen source, the method requires harsh reaction conditions and high equipment requirements, and the use of the supported noble metal also increases the cost. Therefore, a clean, economical and effective new production method is needed.

In recent years, titanium dioxide photocatalysis has gained wide attention in light energy conversion, and conduction band electrons e with high reaction activity are generated under ultraviolet irradiation_cb ^-And valence band hole h_vb ⁺And electrons and holes are transferred from the conduction band and the valence band to the surface-adsorbed oxidized and reduced species, respectively, to complete the redox reaction. The reaction is difficult to control because of the production of more radical active species during the reaction. Therefore, the method has important significance in realizing selective reduction reaction under the catalysis condition of titanium dioxide.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a method for regulating and controlling the selectivity of a photocatalytic reduction reaction of unsaturated aldehyde ketone by using a solvent, which comprises the following steps: adding a photocatalyst, unsaturated aldehyde ketone and a solvent into a reaction vessel, wherein the solvent comprises alcohol, irradiating the reaction vessel with a light source to perform reaction under the oxygen-free condition, and obtaining reduction products with different selectivities by adjusting the proportion and/or the type of the alcohol in the solvent.

According to an embodiment of the present invention, the solvent may be an alcohol or a mixture of an alcohol and an inert organic solvent; when the solvent is a mixture of alcohol and inert organic solvent, the ratio of alcohol to inert organic solvent in the mixture may be (1-10): (1-10), preferably (1-10): 5-10), such as 1:9, 2:8, 3:7, 4:6, 5: 5.

According to an embodiment of the invention, the alcohol may be C_1-6One or more of alkyl alcohol compounds, preferably C_1-4One or more of alkyl alcohol compounds, such as one or more of methanol, ethanol, propanol, isopropanol.

According to an embodiment of the invention, the inert organic solvent may be an aprotic solvent, preferably one or more of acetonitrile, DMF, DMSO, n-hexane, e.g. acetonitrile.

According to an embodiment of the present invention, the photocatalyst may be titanium dioxide, preferably one or more of type a titanium dioxide, type P25 titanium dioxide.

According to an embodiment of the present invention, the unsaturated aldehyde-ketone may be C ═ C conjugated with C ═ O_6-24Aliphatic or aromatic aldehyde ketones, preferably C ═ C conjugated with C ═ O_6-12Aliphatic or aromatic aldehyde ketones, such as one or more of cinnamaldehyde, α -methyl cinnamaldehyde, trans-2-hexenal, 3-methyl-2-butenal.

According to an embodiment of the present invention, the concentration of the photocatalyst may be 0.1 to 5g/L, preferably 0.5 to 2g/L, for example 1 g/L.

According to an embodiment of the present invention, the concentration of the unsaturated aldehyde ketone may be 0.01 to 5mmol/L, preferably 0.05 to 1mmol/L, such as 0.1 mmol/L.

According to an embodiment of the invention, the reactor is a transparent reactor, preferably a glass reactor, e.g. a double-layer glass reactor.

According to an embodiment of the invention, the oxygen-free conditions may be achieved by bubbling an inert gas through the reaction vessel.

Preferably, the reactor is sealed after an inert gas is bubbled to remove oxygen therefrom.

According to an embodiment of the invention, the inert gas is generated in the reaction vessel at a pressure of 0.02MPa to 0.1 MPa.

According to an embodiment of the present invention, the inert gas may be one or more of nitrogen, helium, and argon.

According to the embodiment of the invention, the light source is ultraviolet and visible light with the wavelength of 360-720 nm, and the irradiation is carried out under stirring; the light source may be provided by a xenon lamp, which may have a power of 300W.

According to an embodiment of the present invention, the irradiation time of the light source is 10min to 120min, preferably 40 min to 80min, for example 60 min.

According to an embodiment of the invention, the temperature of the reaction may be between 10 ℃ and 40 ℃, preferably between 20 ℃ and 30 ℃, for example 25 ℃.

According to the embodiment of the invention, the selectivity of the photocatalytic reduction reaction of unsaturated aldehyde ketone under the regulation and control of the method is more than or equal to 45%, preferably more than or equal to 62%, and more preferably more than or equal to 89%.

According to the embodiment of the invention, the yield of the photocatalytic reduction reaction of unsaturated aldehyde ketone under the regulation of the method can be more than or equal to 64%, preferably more than or equal to 82%, more preferably more than or equal to 95%, such as 82%, 95% and 98%.

The invention has the beneficial effects that:

the invention discloses a method for regulating and controlling selectivity of a photocatalytic reduction reaction of unsaturated aldehyde ketone by using a solvent. The method has the advantages of simple operation, good selectivity and high yield, wherein the selectivity can reach 100% at most, and the yield can reach 100% at most.

Detailed Description

The method of the present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.

The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.