Patent Description:
Using <NUM>-ethyl-<NUM>-hydroxymethyloxetane as raw material, the etherification reaction with a halogenated organic compound under the action of a base can obtain a series of oxetane derivatives, which can be used as monomers in a photocurable cation system, and applied in the fields of photocurable inks, coatings, adhesives, and the like. The representative products are <NUM>-ethyl-<NUM>-[(oxiranyl-<NUM>-methoxy)methyl]oxetane, bis[<NUM>-ethyl(<NUM>-oxetanyl)methyl]ether, and <NUM>-benzyloxymethyl-<NUM>-ethyloxetane. These oxetane products have become one of the raw materials having the most promising market potentials in the field of cationic photocuring due to their low viscosity, good dilutability, fast crosslinking rate, and excellent performances after film-forming.

Taking <NUM>-ethyl-<NUM>-[(oxiranyl-<NUM>-methoxy)methyl]oxetane as an example, its industrial production is to use <NUM>-ethyl-<NUM>-hydroxymethyloxetane and epichlorohydrin as raw materials for etherification reaction under the action of solid sodium hydroxide. Since the reaction system is a liquid-solid heterogeneous phase and the mass transfer is relatively difficult, there should be an excess of more than <NUM> % of epichlorohydrin and sodium hydroxide in order to ensure the conversion rate. The production is conducted in a <NUM><NUM> reaction kettle, and the reaction process takes about <NUM>. The post-treatments including filtration, rectification, and other processes take about <NUM>. The operation of adding solid sodium hydroxide in batches during the reaction is cumbersome and has safety hazards such as temperature runaway.

In view of the existence of the above problems, it is necessary to provide a method for synthesizing an oxetane derivative with short reaction time, high mass transfer efficiency, and good safety. <NPL>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT> and <CIT> disclose methods for synthesizing oxetane derivative. <NPL>; <NPL>; <CIT> disclose the use of microreactors.

A main object of the invention is to provide a method for synthesizing an oxetane derivative in a microreactor, so as to solve the problems present in the existing synthesis methods for oxetane derivatives such as long reaction time, cumbersome operations, and poor safety. The selectivity of etherification reaction is ensured while realizing the continuous production, and the product yield is improved.

In order to achieve the above object, the invention provides a method for synthesizing an oxetane derivative in a microreactor, the oxetane derivative having the structure shown in Formula (I):
<CHM>
wherein R is a C<NUM> to C<NUM> linear or branched alkyl, an alkyl containing ethylene oxide structure, an alkyl containing oxetane structure, phenyl, tolyl, benzyl, or biphenyl, and n is <NUM>-<NUM>; the method for synthesizing an oxetane derivative by a microreactor as above comprising: feeding <NUM>-ethyl-<NUM>-hydroxymethyloxetane, a raw material Ha, a catalyst, and a base into a microreactor for etherification reaction to obtain an etherification product, wherein the raw material Ha has a general formula of R-(X)n, and X is halogen; and submitting the etherification product to separation to obtain the oxetane derivative.

In the invention the microreactor has a reaction channel having an inner diameter of <NUM> to <NUM>,<NUM>.

Further, the base is an alkali metal compound or an aqueous solution of alkali metal compound, and the alkali metal compound is selected from one or more of the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, and calcium hydroxide; preferably, the alkali metal compound is sodium hydroxide; the concentration of the aqueous solution of alkali metal compound is <NUM> % to <NUM> %; and the catalyst is selected from one or more of the group consisting of polyethers, cyclic polyethers, and quaternary ammonium salts.

Further, the catalyst is selected from one or more of the group consisting of polyethylene glycol, polyethylene glycol alkyl ether, <NUM>-crown-<NUM>, <NUM>-crown-<NUM>, tetraethylammonium bromide, tetrabutylammonium bromide, tetrabutylammonium chloride, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecyltrimethylammonium chloride.

Further, the catalyst is selected from one or more of the group consisting of polyethylene glycol dimethyl ether, <NUM>-crown-<NUM>, and tetrabutylammonium bromide.

Further, based on the weight of <NUM>-ethyl-<NUM>-hydroxymethyloxetane, the catalyst is added in an amount of <NUM> % to <NUM> % by weight.

Further, the reaction temperature of the etherification reaction is <NUM> to <NUM>, and the residence time of materials is <NUM> to <NUM>.

Further, the device used in the separation step comprises a secondary thin-film evaporation device or a rectification tower.

Further, the microreactor has a reaction channel having an inner diameter of <NUM> to <NUM>,<NUM>.

By applying the technical solution of the invention, the microreactor the advantages, such as high heat and mass transfer coefficient, good mixing performance, easy temperature control, and safe and controllable process as compared to conventional reactors. The advantages of the use of a microreactor in the preparation of oxetane derivative can greatly improve the mass and heat transfer performances of the reaction system, reduce the reaction time, improve the production efficiency, improve the product yield, realize the process continuity and automation, and improve the process safety. Limiting the aperture of the reaction channel of the microreactor within the above-mentioned range is beneficial to improving the selectivity of the etherification reaction, thereby contributing to improving the conversion rate of the oxetane derivative. In addition, the above synthesis process requires small size for reaction device, small floor space for production site, and less manpower, and has high safety.

The accompanying drawing as a part of the subject application is used to provide further understandings on the invention. The exemplary embodiments and their descriptions in the invention are used to explain the invention and do not serve as improper limitations to the invention. In the accompanying drawing:
<FIG> shows a schematic diagram for the structure of a device for preparing an oxetane derivative provided according to a typical embodiment of invention.

Among others, the above drawing includes the following reference signs:.

It should be noted that, in the case of no conflict, the embodiments in the subject application as well as the features therein can be combined with each other. The invention will be described in detail below with reference to the embodiments.

As described in the background, the existing synthesis methods for oxetane derivatives have problems such as long reaction time, cumbersome operations, and poor safety. In order to solve the above technical problems, the invention provides a method for synthesizing an oxetane derivative in a microreactor, the oxetane derivative having the structure shown in Formula (I):
<CHM>
wherein R is a C<NUM> to C<NUM> linear or branched alkyl, an alkyl containing ethylene oxide structure, an alkyl containing oxetane structure, phenyl, tolyl, benzyl, or biphenyl, and n is <NUM>-<NUM>; this method for synthesizing an oxetane derivative comprising: feeding <NUM>-ethyl-<NUM>-hydroxymethyloxetane, a raw material Ha, a catalyst, and a base into a microreactor for etherification reaction to obtain an etherification product, wherein the raw material Ha has a general formula of R-(X)n, and X is halogen; and submitting the etherification product to separation to obtain the oxetane derivative.

The microreactor has advantages, such as high heat and mass transfer coefficient, good mixing performance, easy temperature control, and safe and controllable process as compared to conventional reactors. The advantages of the use of a microreactor in the preparation of oxetane derivative can greatly improve the mass and heat transfer performances of the reaction system, reduce the reaction time, improve the production efficiency, improve the product yield, realize the process continuity and automation, and improve the process safety. In addition, the above synthesis process requires small size for reaction device, small floor space for production site, and less manpower, and has high safety.

The microreactor has a reaction channel having an inner diameter of <NUM> to <NUM>,<NUM>. Limiting the aperture of the reaction channel of the microreactor within the above-mentioned range is beneficial to improving the selectivity of the etherification reaction, and further improves the conversion rate of the oxetane derivative. For example, the microreactor has a reaction channel having an inner diameter of <NUM>, <NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, or <NUM>,<NUM>, and preferably, the microreactor has a reaction channel having an inner diameter of <NUM> to <NUM>,<NUM>.

In the above synthesis method, the base is an alkali metal compound or an aqueous solution of alkali metal compound. The alkali metal compound can be selected from those commonly used in the art. Preferably, the alkali metal compound includes but is not limited to one or more of the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, and calcium hydroxide; more preferably, the alkali metal compound is sodium hydroxide; and the concentration of the aqueous solution of alkali metal compound is <NUM> % to <NUM> %.

In the above synthesis method, the catalyst can be selected from those commonly used in the art. The catalyst includes but is not limited to one or more of the group consisting of polyethers, cyclic polyethers, and quaternary ammonium salts. Preferably, the catalyst includes but is not limited to one or more of the group consisting of polyethylene glycol, polyethylene glycol alkyl ether, <NUM>-crown-<NUM>, <NUM>-crown-<NUM>, tetraethylammonium bromide, tetrabutylammonium bromide, tetrabutylammonium chloride, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecyltrimethylammonium chloride. Compared with other catalysts, the use of the above catalysts is beneficial to further improving the reaction rate of etherification reaction and shortening the reaction period. More preferably, the catalyst includes but is not limited to one or more of the group consisting of polyethylene glycol dimethyl ether, <NUM>-crown-<NUM>, and tetrabutylammonium bromide.

In a preferred embodiment, based on the weight of <NUM>-ethyl-<NUM>-hydroxymethyloxetane, the catalyst is added in an amount of <NUM> % to <NUM> % by weight. The amount of the catalyst includes but is not limited to the above-mentioned range, while limiting it within the above-mentioned range is beneficial to further improving the reaction rate of the etherification reaction. For example, based on the weight of <NUM>-ethyl-<NUM>-hydroxymethyloxetane, the catalyst is added in an amount of <NUM> %, <NUM> %, <NUM> %, <NUM> %, <NUM> %, <NUM> %, or <NUM> % by weight. More preferably, based on the weight of <NUM>-ethyl-<NUM>-hydroxymethyloxetane, the catalyst is added in an amount of <NUM> % to <NUM> % by weight.

In a preferred embodiment, the molar ratio of <NUM>-ethyl-<NUM>-hydroxymethyloxetane to the halogen in the raw material Ha is <NUM>: (<NUM> to <NUM>). The molar ratio of <NUM>-ethyl-<NUM>-hydroxymethyloxetane to the halogen in the raw material Ha includes but is not limited to the above-mentioned range, while limiting it within the above-mentioned range is beneficial to improving the conversion rate of <NUM>-ethyl-<NUM>-hydroxymethyloxetane.

In a preferred embodiment, the reaction temperature of the etherification reaction is <NUM> to <NUM>, and the residence time of materials is <NUM> to <NUM>. The reaction temperature of the etherification reaction and the residence time of materials include but are not limited to the above-mentioned ranges, while limiting them within the above-mentioned ranges is beneficial to further improving the yield of the etherification product. For example, the reaction temperature of the etherification reaction can be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>.

The above separation step can be conducted using a device commonly used in the art. Preferably, the device used in the separation step includes: a secondary thin-film evaporation device or a rectification tower.

The subject application is further described in detail below with reference to specific examples, which cannot be understood as limiting the claimed scope in the subject application.

In the examples, the device shown in <FIG> was used to prepare the oxetane derivative, and the synthesis method included the following steps:.

It differed from Example <NUM> in that: the microreactor has a reaction channel having an inner diameter of <NUM>.

The selectivity for <NUM>-ethyl-<NUM>-[(oxiranyl-<NUM>-methoxy)methyl]oxetane was <NUM> %, with a yield of <NUM> %.

It differed from Example <NUM> in that: the microreactor has a reaction channel having a size of <NUM>,<NUM>.

The selectivity for <NUM>-ethyl-<NUM>-[(oxiranyl-<NUM>-methoxy)methyl]oxetane was <NUM> %, with a yield of <NUM> wt %.

It differed from Example <NUM> in that: the catalyst was added in an amount of <NUM> %, the catalyst was polyethylene glycol dimethyl ether, and the residence time of materials was <NUM>.

It differed from Example <NUM> in that: the catalyst was added in an amount of <NUM> %, the catalyst was <NUM>-crown-<NUM>, and the residence time of materials was <NUM>.

It differed from Example <NUM> in that: the catalyst was added in an amount of <NUM> %, the catalyst was polyethylene glycol, and the residence time of materials was <NUM>.

It differed from Example <NUM> in that: the catalyst was added in an amount of <NUM> %, the catalyst was tetradecyltrimethylammonium chloride, and the residence time of materials was <NUM>.

It differed from Example <NUM> in that: the reaction temperature of the etherification reaction was <NUM>.

It differed from Example <NUM> in that: the stoichiometric amounts of <NUM>-ethyl-<NUM>-hydroxymethyloxetane (MOX101), caustic soda flakes, and catalyst were mixed well and charged into the organic raw material storage tank <NUM>, and epichlorohydrin was charged into the raw material storage tank <NUM>, wherein the microreactor has a reaction channel having an inner diameter of <NUM>.

It differed from Example <NUM> in that: the stoichiometric amounts of <NUM>-ethyl-<NUM>-hydroxymethyloxetane (MOX101), epichlorohydrin, and catalyst were mixed well and charged into the organic raw material storage tank <NUM>, and the base solution was charged into the raw material storage tank <NUM>, wherein the microreactor has a reaction channel having an inner diameter of <NUM>,<NUM>.

It differed from Example <NUM> in that: the catalyst was added in an amount of <NUM> %, the catalyst was tetrabutylammonium bromide, and the residence time of materials was <NUM>.

It differed from Example <NUM> in that: the stoichiometric amounts of <NUM>-ethyl-<NUM>-hydroxymethyloxetane (MOX101) and caustic soda flakes were mixed well and charged into the organic raw material storage tank <NUM>, and epichlorohydrin and catalyst were charged into the raw material storage tank <NUM>, wherein the catalyst was added in an amount of <NUM> %, the catalyst was <NUM>-crown-<NUM>, and the residence time of materials was <NUM>.

It differed from Example <NUM> in that: the stoichiometric amounts of <NUM>-ethyl-<NUM>-hydroxymethyloxetane (MOX101) and caustic soda flakes were mixed well and charged into the organic raw material storage tank <NUM>, and epichlorohydrin and catalyst were charged into the raw material storage tank <NUM>, wherein the catalyst was added in an amount of <NUM> %, the catalyst was tetrabutylammonium bromide, and the residence time of materials was <NUM>.

In Comparative Examples <NUM> to <NUM>, a conventional reactor was used to prepare the oxetane derivative, and the specific process parameters were shown in Table <NUM>. The synthesis method included the following steps:
Into a four-necked flask <NUM>-ethyl-<NUM>-hydroxymethyloxetane (MOX101) and raw material R-(X)n were added and stirred to mix well; the base solution and catalyst were mixed well and dropwise added into the above four-necked flask; after the dropwise addition was completed, the reaction was conducted under heat preservation; the organic phase was taken for detecting the conversion rate by GC, and the reaction was stopped after the conversion rate no longer changed; and the reaction product system was allowed to stand for phase separation, then subjected to rectification to obtain the finished product.

From the above descriptions, it can be seen that the above embodiments of the invention achieve the following technical effects:.

By comparing Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM>, it can be seen that adopting the method provided in the subject application is beneficial to the selectivity and yield of oxetane derivative.

By comparing Examples <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, it can be seen that limiting the inner diameter of the reaction channel of the microreactor within the range of the subject application is beneficial to improving the selectivity and yield of oxetane derivative.

Claim 1:
A method for synthesizing an oxetane derivative in a microreactor, the oxetane derivative having the structure shown in Formula (I):
<CHM>
wherein R is a C2 to C12 linear or branched alkyl, an alkyl containing ethylene oxide structure, an alkyl containing oxetane structure, phenyl, tolyl, benzyl, or biphenyl, and n is <NUM>-<NUM>;
characterized in that the method comprises:
feeding <NUM>-ethyl-<NUM>-hydroxymethyloxetane, a raw material Ha, a catalyst, and a base into a microreactor comprising a reaction channel having an inner diameter of <NUM> to <NUM>,<NUM>, for etherification reaction to obtain an etherification product, wherein the raw material Ha has a general formula of R-(X)n, and X is halogen; and
submitting the etherification product to separation to obtain the oxetane derivative.