Synthesis method of oxetane

Abstract

The invention relates to the technical field of cyclobutane synthesis, in particular to a synthetic method of oxetane, which comprises the following steps of: adding two organic monomers, namely 2-(chloromethyl)-2-methyl ethylene oxide and 3-ethyl-3-oxabutyl cyclomethanol, as well as a base catalyst and a dehydrating agent into a reactor for reaction, adding a filter aid into the obtained product for suction filtration, and filtering to obtain a filtrate; 2-(chloromethyl)-2-methyl ethylene oxide is added in the suction filtration process to wash a filter cake, then vacuum rectification is conducted, fractions at 45-50 DEG C / 40-50 mmHg are collected, and the target product is obtained. According to the invention, 2-(chloromethyl)-2-methyl ethylene oxide and 3-ethyl-3-oxabutyl cyclomethanol are used as raw materials, alkali is directly used as a catalyst, and a phase transfer catalyst does not need to be added, so that the cost of the raw materials is reduced, and the environmental pollution is reduced; meanwhile, the dehydrating agent is added, so that the reaction yield is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cyclobutane synthesis, and in particular to a method for synthesizing oxetane. Background Art

[0002] Cationic photocuring systems are unaffected by oxygen inhibition, have a reduced cured volume, and exhibit excellent adhesion when applied to plastic or metal substrates. Typically, cationic photocuring systems contain alicyclic epoxy compounds. In the presence of an appropriate photoinitiator and irradiated with light of a suitable wavelength, they produce a cured product with excellent heat resistance, adhesion, and chemical resistance. However, the application of alicyclic epoxy compounds has limitations, most notably their sensitivity to humidity. Water vapor in the application environment can significantly reduce the cure rate. In recent years, the introduction of oxetane compounds into cationic curing systems has become a development trend, believed to improve the performance of the cured product, and has achieved progress in areas such as coating compositions. However, the variety of oxetane compounds in these coating compositions is limited, with limited selectivity, and there is still the issue of humidity sensitivity, and the cured product has an odor. In addition, for solvent-free systems, these compositions generally have a high viscosity, which limits their application in some areas, such as low-viscosity inks. 3-Ethyl-3-(((2-methyloxiran-2-yl)methoxy)methyl)oxetane is a bifunctional UV-curable monomer with wide applications. It is insensitive to humidity and has the advantages of high reactivity, low odor and viscosity, and strong adhesion.

[0003] Chinese patent publication number CN119504719A discloses a method for synthesizing 3-ethyl-3-[(2-oxiranylmethoxy)methyl]oxetane, which uses sodium hydroxide as an alkaline reagent and a quaternary ammonium salt or quaternary phosphonium salt phase transfer catalyst to promote the effective contact between the generated sodium salt and epichlorohydrin, thereby catalyzing the conversion of 3-ethyl-3-oxetanemethanol and epichlorohydrin to prepare 3-ethyl-3-[(2-oxiranylmethoxy)methyl]oxetane.

[0004] In addition to adding alkali, the patented preparation process also requires the use of quaternary ammonium salt or quaternary phosphonium salt phase transfer catalyst, which has the disadvantages of high cost and certain pollution to the environment. Summary of the Invention

[0005] The present invention solves the problems in the related art and proposes a method for synthesizing oxetane. 2-(chloromethyl)-2-methyloxirane and 3-ethyl-3-oxetane methanol are used as raw materials. A base is directly used as a catalyst without adding a phase transfer catalyst, thereby reducing raw material costs and environmental pollution. At the same time, the addition of a dehydrating agent greatly improves the reaction yield.

[0006] In order to solve the above technical problems, the present invention is achieved through the following technical solutions: a method for synthesizing oxetane, the structural formula of oxetane is as follows:

[0007]

[0008] The preparation method is as follows:

[0009] Step 1: Add two organic monomers, 2-(chloromethyl)-2-methyloxirane and 3-ethyl-3-oxetanol, a base catalyst, and a dehydrating agent into a reactor, and react at 100-120° C. until the content of 3-ethyl-3-oxetanol in the reaction system is less than 5 wt%, and then stop the reaction;

[0010] Step 2: Add a filter aid to the product obtained in step 1 and filter it with suction. During the filtration process, add 2-(chloromethyl)-2-methyloxirane to wash the filter cake. The raw materials used in the washing are collected together in the filtrate. The filtrate contains a mixture of the product and 2-(chloromethyl)-2-methyloxirane.

[0011] Step 3: The product obtained in step 2 is subjected to vacuum distillation, and the fraction at 45-50°C / 40-50 mmHg is collected, which is the target product 3-ethyl-3-(((2-methyloxirane-2-yl)methoxy)methyl)oxetane. At the same time, the raw material 2-(chloromethyl)-2-methyloxirane is recovered by distillation.

[0012] As a preferred embodiment, the alkaline catalyst is at least one of potassium hydroxide, sodium hydroxide, calcium hydroxide, sodium methoxide, sodium ethoxide, and sodium tert-butoxide.

[0013] As a preferred embodiment, the dehydrating agent is at least one of calcium oxide, molecular sieve, and aluminum oxide.

[0014] As a preferred embodiment, the molar ratio of the 3-ethyl-3-oxetanol and the 2-(chloromethyl)-2-methyloxirane is 1:1-8.

[0015] As a preferred embodiment, the molar ratio of the 3-ethyl-3-oxetanol to the base catalyst is 1:0.5-2.

[0016] As a preferred embodiment, the filter aid is at least one of diatomaceous earth, white clay, and activated carbon.

[0017] As a preferred embodiment, the mass ratio of the 3-ethyl-3-oxetanol to the dehydrating agent is 1:1-2.

[0018] Compared with the prior art, the present invention has the following beneficial effects: the present invention uses 2-(chloromethyl)-2-methyloxirane and 3-ethyl-3-oxetanol as raw materials, directly uses a base as a catalyst, and does not need to add a quaternary ammonium salt or a quaternary phosphonium salt phase transfer catalyst, thereby reducing raw material costs and reducing environmental pollution; at the same time, by adding a dehydrating agent, the reaction yield is greatly improved, and can be increased from an initial 50% to 85% to 91%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the NMR spectrum of the target compound 3-ethyl-3-(((2-methyloxiran-2-yl)methoxy)methyl)oxetane prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. Technology and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and methods should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values.

[0022] In the following examples, the experimental methods without specific conditions are generally measured according to national standards; if there is no corresponding national standard, the general standard requirements or general methods are used.

[0023] Example 1

[0024] To a four-necked flask equipped with a stirring device, a thermometer, and a reflux condenser, 3-ethyl-3-oxetane methanol (258 mmol, 1 eq) 30 g, 2-(chloromethyl)-2-methyloxirane (1.29 mol, 5 eq) 137.59 g, 21.74 g potassium hydroxide (387 mmol, 1.5 eq) and 30 g anhydrous calcium oxide dehydrating agent were added in sequence, and the reaction was carried out at 100 ° C. for 5 h. The gas phase was tracked until the reaction raw material 3-ethyl-3-oxetane methanol completely disappeared. After the reaction was completed, diatomaceous earth was added as a filter aid and stirred thoroughly, and filtered. During filtration, 137.59 g (5.0 eq) of 2-(chloromethyl)-2-methyloxirane was used to clean the filter cake and the reaction bottle. The washed solvent was collected together in the filtrate to obtain a mixture of the product and the raw material 3-ethyl-3-oxetane methanol.

[0025] The resulting crude product mixture was placed in a single-necked flask and connected to a vacuum distillation apparatus. The fractions at 45-50°C / 40-50 mmHg were collected to obtain a colorless, transparent, low-viscosity liquid product. Simultaneously, the raw material 2-(chloromethyl)-2-methyloxirane was recovered by distillation. The product yield was 85.95%, the GC purity was 94.84%, and the viscosity was approximately 349 mp·s.

[0026] The structure and purity of the product were confirmed by GC-MS and H-NMR.

[0027] Example 2

[0028] To a four-necked flask equipped with a stirring device, a thermometer, and a reflux condenser, 30 g of 3-ethyl-3-oxetane methanol (258 mmol, 1 eq), 137.59 g of 2-(chloromethyl)-2-methyloxirane (1.29 mol, 5 eq), 21.74 g of potassium hydroxide (387 mmol, 1.5 eq) and 30 g of a molecular sieve dehydrating agent were added sequentially, and the reaction was carried out at 100 ° C for 5 h. The gas phase was tracked until the reaction raw material 3-ethyl-3-oxetane methanol completely disappeared. After the reaction was completed, a filter aid, white clay, was added and stirred thoroughly, and the mixture was filtered. During the filtration, 137.59 g (5.0 eq) of 2-(chloromethyl)-2-methyloxirane was used to clean the filter cake and the reaction flask. The washed raw materials were pooled together in the filtrate to obtain a mixture of the product and the raw material 3-ethyl-3-oxetane methanol.

[0029] The resulting crude product mixture was placed in a single-necked flask and connected to a vacuum distillation apparatus. The fractions at 45-50°C / 40-50 mmHg were collected to obtain a colorless, transparent, low-viscosity liquid product. Simultaneously, the raw material 2-(chloromethyl)-2-methyloxirane was recovered by distillation. The product yield was 86.75%, the GC purity was 93.52%, and the viscosity was approximately 353 mp·s.

[0030] The structure and purity of the product were confirmed by GC-MS and H-NMR.

[0031] Example 3

[0032] To a four-necked flask equipped with a stirring device, a thermometer, and a reflux condenser were added 30 g of 3-ethyl-3-oxetane methanol (258 mmol, 1 eq), 137.59 g of 2-(chloromethyl)-2-methyloxirane (1.29 mol, 5 eq), and 21.74 g of potassium hydroxide (387 mmol, 1.5 eq). The reaction was carried out at 100 ° C for 5 h, and the gas phase was tracked until the reaction raw material 3-ethyl-3-oxetane methanol completely disappeared. After the reaction was completed, a filter aid, white clay, was added and stirred thoroughly, and the mixture was filtered. During filtration, 2-(chloromethyl)-2-methyloxirane was used to clean the filter cake and the reaction flask. The washed raw materials were pooled together in the filtrate to obtain a mixture of the product and the raw material 3-ethyl-3-oxetane methanol.

[0033] The resulting crude product mixture was placed in a single-necked flask and connected to a vacuum distillation apparatus. The fractions at 45-50°C / 40-50 mmHg were collected to obtain a colorless, transparent, low-viscosity liquid product. Simultaneously, the raw material 2-(chloromethyl)-2-methyloxirane was recovered by distillation. The product yield was 56.75%, the GC purity was 6.59%, and the viscosity was approximately 353 mp·s.

[0034] The structure and purity of the product were confirmed by GC-MS and H-NMR.

[0035] The above are preferred embodiments of the present invention. Those skilled in the art to which the present invention belongs can also change and modify the above embodiments. Therefore, the present invention is not limited to the above specific embodiments. Any obvious improvements, replacements or modifications made by those skilled in the art on the basis of the present invention fall within the scope of protection of the present invention.

Claims

1. A method for synthesizing oxetane, characterized in that: The structural formula of oxetane is as follows: The preparation method is as follows: Step 1: Add two organic monomers, 2-(chloromethyl)-2-methyloxirane and 3-ethyl-3-oxetanol, a base catalyst, and a dehydrating agent into a reactor, and react at 100-120° C. until the content of 3-ethyl-3-oxetanol in the reaction system is less than 5 wt%, and then stop the reaction; Step 2: Add a filter aid to the product obtained in step 1 and filter it with suction. During the filtration process, add 2-(chloromethyl)-2-methyloxirane to wash the filter cake. The raw materials used in the washing are collected together in the filtrate. The filtrate contains a mixture of the product and 2-(chloromethyl)-2-methyloxirane. Step 3: The product obtained in step 2 is subjected to vacuum distillation, and the fraction at 45-50°C / 40-50 mmHg is collected, which is the target product 3-ethyl-3-(((2-methyloxirane-2-yl)methoxy)methyl)oxetane. At the same time, the raw material 2-(chloromethyl)-2-methyloxirane is recovered by distillation.

2. The method for synthesizing oxetane according to claim 1, wherein: The alkaline catalyst is at least one of potassium hydroxide, sodium hydroxide, calcium hydroxide, sodium methoxide, sodium ethoxide, and sodium tert-butoxide.

3. The method for synthesizing oxetane according to claim 1, wherein: The dehydrating agent is at least one of calcium oxide, molecular sieve and aluminum oxide.

4. The method for synthesizing oxetane according to claim 1, wherein: The molar ratio of the 3-ethyl-3-oxetanol and 2-(chloromethyl)-2-methyloxirane is 1:1-8.

5. The method for synthesizing oxetane according to claim 1, wherein: The molar ratio of the 3-ethyl-3-oxetanol to the base catalyst is 1:0.5-2.

6. The method for synthesizing oxetane according to claim 1, wherein: The filter aid is at least one of diatomaceous earth, white clay, and activated carbon.

7. The method for synthesizing oxetane according to claim 1, wherein: The mass ratio of the 3-ethyl-3-oxetanol to the dehydrating agent is 1:1-2.

Images