阅读说明：本技术 一种气氛煅烧调控溴苯乙酮选择性还原的方法和应用 (Method for regulating and controlling bromoacetophenone selective reduction through atmosphere calcination and application ) 是由 舒细记 商锦婷 孙宾莲 柳威 包建 雷磊 刘钰晨 于 2020-12-31 设计创作，主要内容包括：本发明公开了一种气氛煅烧调控溴苯乙酮选择性还原的方法和应用,所述方法包括：将二氧化钛在惰性气体气氛下,于450℃煅烧进行改性,然后以改性后的二氧化钛作为催化剂,光催化溴苯乙酮的选择性还原。本发明将二氧化钛于450℃下煅烧改性,根据煅烧时间的不同,得到不同氧空位浓度的二氧化钛样品,并用改性后的二氧化钛光催化溴苯乙酮的还原。通过调节煅烧时间的长短,可调控溴苯乙酮还原的选择性,进而得到了溴苯基乙醇或苯乙酮与溴苯基乙醇的混合物。并且Br在苯环上的取代位置发生变化时,该规律仍然存在。采用该方法可人为调控溴苯乙酮的还原反应,以获得重要的有机合成中间体苯乙酮或溴苯基乙醇,且制备方法简单快速,适合大规模广泛应用。(The invention discloses a method for regulating and controlling bromoacetophenone selective reduction through atmosphere calcination and application, wherein the method comprises the following steps: calcining titanium dioxide at 450 ℃ in an inert gas atmosphere for modification, and then carrying out photocatalysis on the bromoacetophenone selective reduction by using the modified titanium dioxide as a catalyst. According to the invention, titanium dioxide is calcined and modified at 450 ℃, titanium dioxide samples with different oxygen vacancy concentrations are obtained according to different calcination times, and the modified titanium dioxide is used for photocatalysis reduction of bromoacetophenone. The reduction selectivity of bromoacetophenone can be regulated by regulating the calcination time, and then the bromoxyethanol or the mixture of the acetophenone and the bromoxyethanol is obtained. And the substitution position of Br on the benzene ring is changed, the rule still exists. The method can be used for manually regulating and controlling the reduction reaction of bromoacetophenone to obtain an important organic synthesis intermediate acetophenone or bromophenyl ethanol, is simple and quick, and is suitable for large-scale wide application.)

1. A method for catalyzing bromoacetophenone selective reduction by titanium dioxide through atmosphere calcination regulation is characterized by comprising the following steps: calcining titanium dioxide at 450 ℃ in an inert gas atmosphere for modification, and then carrying out photocatalysis on the bromoacetophenone selective reduction by using the modified titanium dioxide as a catalyst.

2. The method of claim 1, wherein the calcination is carried out for a time of 0 to 12 hours.

3. The method according to claim 2, wherein when the calcination time is 0h, all of the reduction products of bromoacetophenone are C ═ O bond reduction products; the reduction products of the bromoacetophenone have increased C-Br bond reduction products as the calcination time is prolonged, and the reduction products of the bromoacetophenone are a mixture of the reduction products of the C ═ O bond and the reduction products of the C-Br bond.

4. The method of claim 1, wherein the inert gas is hydrogen argon.

5. The method according to claim 1, characterized in that the method is: calcining titanium dioxide at 450 ℃ in an inert gas atmosphere to modify the titanium dioxide to obtain modified titanium dioxide, dissolving bromoacetophenone and the modified titanium dioxide by using methanol, then adding a sodium hydroxide alcohol solution, and carrying out photocatalysis on the bromoacetophenone by using the modified titanium dioxide in the inert gas atmosphere at 25 ℃.

6. Use of a process according to any one of claims 1 to 5 for the preparation of bromophenylethanol.

7. Use of a process according to any one of claims 1 to 5 for the preparation of a mixture of bromophenyl ethanol and acetophenone.

Technical Field

The invention belongs to the technical field of bromoacetophenone reduction, and particularly relates to a method for regulating bromoacetophenone selective reduction through atmosphere calcination and application.

Background

Bromoacetophenone is an important organic synthesis raw material, and is widely applied to the fields of spices, medicines, pesticides, dyes, organic photoelectricity and the like. According to the difference of reaction conditions, bromoacetophenone can undergo selective reduction reaction to produce important organic synthesis intermediate acetophenone or bromoxyethanol, for example, acetophenone can be used for making perfumed soap and cigarette, also can be used as intermediate of organic chemical synthesis, solvent of fiber resin and the like and plasticizer of plastics, and also can be used for blending edible essence of cherry, Chinese sage, tomato, strawberry, apricot and the like or essence for cigarette.

Titanium dioxide is a white solid or powdery amphoteric oxide, has no toxicity, optimal opacity, optimal whiteness and brightness, is considered to be a white pigment with the best performance in the world nowadays, and is widely applied to industries such as coatings, plastics, papermaking, printing ink, chemical fibers, rubber, cosmetics and the like. Titanium dioxide is an n-type semiconductor material, has a forbidden band width of 3.2ev (anatase), and when irradiated by light (ultraviolet light) with a wavelength of 387.5nm or less, electrons in the valence band gain photon energy and form photogenerated electrons (e) going forward to the conduction band^-) And photogenerated holes (h) are formed correspondingly in the valence band⁺)。The titanium dioxide has extremely strong oxidation-reduction capability, is a common photocatalyst and can be used for reducing the bromoacetophenone.

Disclosure of Invention

The invention aims to provide a method for regulating bromoacetophenone selective reduction through atmosphere calcination and application thereof.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for catalyzing bromoacetophenone selective reduction by atmosphere-controlled titanium dioxide, the method comprising: calcining titanium dioxide at 450 ℃ in an inert gas atmosphere for modification, and then carrying out photocatalysis on the bromoacetophenone selective reduction by using the modified titanium dioxide as a catalyst.

Further, the calcining time is 0-12 hours.

Further, when the calcination time is 0h, all the reduction products of bromoacetophenone are C ═ O bond reduction products; the reduction products of the bromoacetophenone have increased C-Br bond reduction products as the calcination time is prolonged, and the reduction products of the bromoacetophenone are a mixture of the reduction products of the C ═ O bond and the reduction products of the C-Br bond.

Further, the inert gas is hydrogen-argon mixed gas.

Further, the method comprises the following steps: calcining titanium dioxide at 450 ℃ in an inert gas atmosphere to modify the titanium dioxide to obtain modified titanium dioxide, dissolving bromoacetophenone and the modified titanium dioxide by using methanol, then adding a sodium hydroxide alcohol solution, and carrying out photocatalysis on the bromoacetophenone by using the modified titanium dioxide in the inert gas atmosphere at 25 ℃.

The invention also provides the application of the method in preparing the bromophenyl ethanol.

The invention also provides the application of the method in preparing the mixture of the bromophenyl ethanol and the acetophenone.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, titanium dioxide is calcined at a high temperature of 450 ℃ for modification, titanium dioxide samples with different surface defect concentrations, namely different oxygen vacancy concentrations, are obtained according to different calcination times, and the modified titanium dioxide is used for photocatalysis reduction of bromoacetophenone. The reduction selectivity of bromoacetophenone can be regulated by regulating the calcination time, so that a mixture of a C ═ O bond reduction product bromophenyl ethanol or a C-Br bond reduction product acetophenone and bromophenyl ethanol is obtained, and further, the acetophenone and the bromophenyl ethanol can be separated by separation and purification to respectively obtain the bromophenyl ethanol and the acetophenone. And the substitution position of Br on the benzene ring is changed, the rule still exists. The method can be used for manually regulating and controlling the reduction reaction of bromoacetophenone to obtain an important organic synthesis intermediate acetophenone or bromophenyl ethanol, is simple and quick, and is suitable for large-scale wide application.

Drawings

FIG. 1 shows the distribution of the modified titanium dioxide photocatalytic reduction of 4-bromoacetophenone in accordance with the present invention in example 1, with different calcination times in a mixed gas atmosphere of hydrogen and argon; wherein the abscissa is the reaction time (min), A-H₂-12H represents the calcination of titanium dioxide in a mixture of hydrogen and argon for 12H, A-H₂-4H represents the calcination of titanium dioxide in a mixture of hydrogen and argon for 4H, A-H₂-2H represents the calcination of titanium dioxide in a mixture of hydrogen and argon for 2H; a represents titanium dioxide which is not calcined at high temperature; the bottom graph shows the top graph before photocatalytic reduction of 4-bromoacetophenone.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The sources of the instrument equipment and the material reagent adopted in the embodiment of the invention are as follows:

anatase type titanium dioxide, 4-bromoacetophenone, 2-bromoacetophenone, 3-bromoacetophenone, methanol and sodium hydroxide are all purchased from national pharmaceutical group chemical reagent company Limited;

a circulating constant-temperature water bath kettle which is sourced from Beijing Changhui scientific instruments, Inc.;

xenon lamps from Beijing Aulight Technology co, ltd;

high performance liquid chromatography instrument from Thermo.

Example 1

The embodiment takes 4-bromoacetophenone as an example, and provides a method for regulating and controlling selective reduction of titanium dioxide photocatalytic bromoacetophenone by atmosphere calcination, which specifically comprises the following steps:

anatase titanium dioxide was weighed separately and charged in a tube furnace in a 5% hydrogen argon mixture (containing 5% H)₂And 95% Ar) at 450 ℃, preparing titanium dioxide samples with different oxygen vacancy concentrations by controlling the calcination time, and obtaining A, A-H by calcining for 0H, 2H, 4H and 12H respectively₂-2H、A-H₂-4H and A-H₂The temperature rising and reducing rates of the-12H sample in the calcining process are all 5 ℃ for min^-1。

Separately weighing A, A-H₂-2H、A-H₂-4H and A-H₂Dissolving a-12H sample into methanol to a concentration of 1g/L, adding 2-bromoacetophenone to a concentration of 0.1mM, adding a sodium hydroxide alcoholic solution of 0.5mM, filling the mixture into a double-layer glass bottle reactor, purging with argon for 20min, and sealing;

then, the temperature is controlled at 25 ℃ by using a circulating water bath and the stirring is continued, the illumination below 360nm is filtered by using a 300W xenon lamp, the reduction reaction of the 4-bromoacetophenone is catalyzed by using the modified titanium dioxide sample, the reaction time is 30min, and the concentration change of reactants and products in the reaction liquid is detected in real time by using a high performance liquid chromatograph, and the result is shown in figure 1.

Wherein the abscissa is the reaction time (min), A-H₂-12H represents the calcination of titanium dioxide in a mixture of hydrogen and argon for 12H, A-H₂-4H tableCalcining titanium dioxide in a mixed gas of hydrogen and argon for 4H, A-H₂2H represents the calcination of the titanium dioxide in a hydrogen-argon mixed gas for 2 hours, A represents the calcination for 0 hours, namely the titanium dioxide is not calcined at high temperature; the bottom graph shows the top graph before photocatalytic reduction of 4-bromoacetophenone.

The results show that when titanium dioxide is directly used for photocatalytic reduction of 4-bromoacetophenone without high-temperature calcination, the reaction product is only a C ═ O bond reduction product, i.e., the product is only 1- (4-bromophenyl) ethanol. After high-temperature calcination, the oxygen vacancy concentration of the titanium dioxide is increased along with the extension of the calcination time, and C-Br bond reduction products begin to appear in the products of the 4-bromoacetophenone reduction reaction and gradually increase, namely the products are the mixture of 1- (4-bromophenyl) ethanol and acetophenone. Further, 1- (4-bromophenyl) ethanol and acetophenone may be separated by conventional separation methods to obtain 1- (4-bromophenyl) ethanol and acetophenone, respectively. The method can realize the selective reduction of bifunctional molecular bromoacetophenone, thereby obtaining different reaction products.

Example 2

The present embodiment is different from embodiment 1 in that: this example replaces 4-bromoacetophenone by either 2-bromoacetophenone or 3-bromoacetophenone.

The result is the same as example 1, when the raw material is 2-bromoacetophenone, when the calcination time is 0h, the reduction product is all 1- (2-bromophenyl) ethanol, the concentration of the acetophenone in the product is gradually increased along with the increase of the calcination time, and the product is a mixture of the 1- (2-bromophenyl) ethanol and the acetophenone; the same applies to 3-bromoacetophenone. The present example is mainly used to verify that when the substitution position of Br on the benzene ring is changed, the change rule of the reduction selectivity of bromoacetophenone and the atmosphere calcination time is the same as that in example 1, that is, the substitution position of Br on the benzene ring has no influence on the selective reduction of bromoacetophenone.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.