Preparation method of 1-propylene-1, 3-sultone

Abstract

The invention belongs to the field of new materials, and discloses a preparation method of 1-propylene-1, 3-sultone, which comprises the following steps: step 1, addition reaction: using propargyl alcohol and alkali metal sulfite and / or alkali metal hydrosulfite as raw materials, and carrying out addition reaction in the presence of a catalyst and a free radical initiator to obtain an addition product; step 2, acidification reaction: adjusting the pH value of the addition product to 4 or below 4, and separating to obtain an acidified product; step 3, cyclization reaction: carrying out cyclization reaction on the acidified product to obtain 1-propylene-1, 3-sultone; the catalyst is soluble metal salt which is soluble in water. According to the method, the catalyst and the free radical initiator which are low in price are compounded, so that a product with relatively good conversion rate and selectivity is obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of new materials, more specifically, it relates to a preparation method of 1-propylene-1,3-sulfolactone. BACKGROUND

[0002] At present, the synthesis route of propylene-1,3-sulfolactone can be summarized into two categories. One is to use electronic grade 1,3-propane sulfolactone as raw material to synthesize propylene-1,3-sulfolactone through halogenation and elimination reaction, or to use 2-hydroxy-1,3-sulfolactone as raw material, and then to generate 1,3-propylene sulfonate through chlorination reaction and elimination reaction with thionyl chloride. The raw material of this scheme is a semi-finished product and has high purity requirement, which is expensive and not suitable for industrial application. The second synthesis route uses propargyl alcohol and alkali metal sulfite or bisulfite as raw materials to carry out addition reaction, and then acidizes to obtain hydroxypropylene sulfonic acid, and then heats to cyclize to obtain product PST. This route has certain economic benefits, and can be used for industrial production because the raw materials are cheaper, the product quality is high and stable, and the waste is less.

[0003] Among them, the second synthesis route has three different synthesis paths:

[0004] Path one: propargyl alcohol and alkali metal sulfite or bisulfite as raw materials, in the presence of a free radical initiator, to generate an addition product, and then to generate the product through acidification, separation and cyclization of the addition product;

[0005] Path two: propargyl alcohol and alkali metal sulfite or bisulfite as raw materials, in the presence of a composite catalyst composed of onium salt and crown ether, to generate an addition product, and then to generate the product through acidification, separation and cyclization of the addition product;

[0006] Path three: propargyl alcohol and alkali metal sulfite or bisulfite as raw materials, in the presence of a composite catalyst composed of 2,2'-azobis isobutylamidine hydrochloride and crown ether with a molar ratio of (10-50):1, to generate an addition product, and then to generate the product through acidification, separation and cyclization of the addition product;

[0007] The advantage of route three is that the addition reaction is very fast. Through gas phase monitoring of the reaction, it can be known that the conversion rate can reach more than 99% within 0.5 hours.

[0008] The problems existing in the above route are:

[0009] Route one: the yield is low. In its application, it is recorded that based on the free radical induced synthesis reaction, the yield is difficult to exceed 80%;

[0010] Route two: onium salt and crown ether are expensive;

[0011] Route three: crown ether is expensive.

[0012] The technical problem solved by the present application is: how to realize the synthesis of propylene-1,3-sulfolactone under the premise of considering efficiency and cost. SUMMARY

[0013] The main purpose of the present application is to provide a preparation method of 1-propylene-1,3-sulfolactone, which uses propargyl alcohol and alkali metal sulfite and / or alkali metal bisulfite as raw materials, and makes the catalyst and the free radical initiator compound, so that the product has good conversion rate and selectivity; at the same time, the prices of raw materials, catalysts and free radical initiators are low.

[0014] According to the first aspect of the present application, a preparation method of 1-propylene-1,3-sulfolactone is provided, comprising the following steps:

[0015] Step 1: addition reaction, using propargyl alcohol and alkali metal sulfite and / or alkali metal bisulfite as raw materials, and carrying out addition reaction in the presence of catalyst and free radical initiator to obtain addition product;

[0016] Step 2: acidification reaction, adjusting the pH value of the addition product to 4 or below 4 to separate and obtain acidification product;

[0017] Step 3: cyclization reaction, cyclizing the acidification product to obtain 1-propylene-1,3-sulfolactone;

[0018] The catalyst is a soluble metal salt soluble in water.

[0019] When the above free radical initiator and the above soluble metal salt are used in combination to synthesize 1-propylene-1,3-sulfolactone, it is found that the conversion rate and the reaction rate are obviously improved, effectively overcoming the problem of low conversion rate of the addition reaction when any of the traditional free radical initiator and the soluble metal salt is used in the present application. The principle is: propargyl alcohol as a typical terminal alkyne has smaller steric hindrance than non-terminal alkyne, and transition metal salt can effectively catalyze free radical reaction to realize alkyne addition; at the same time, in the sodium bisulfite system, the free radicals formed by the initiator will couple with the free radicals of copper alkynyl to form a unique sp bond, realizing the direct sulfonation of terminal alkyne, effectively improving the conversion of addition reaction, and effectively solving the problems of slow reaction rate and low sulfonation conversion rate in the sulfonation of propargyl alcohol.

[0020] In the acidification reaction, the terminal pH value is controlled to 4 or below 4 to avoid incomplete acidification or excessive acidification and carbonization, which affects the yield of the subsequent cyclization reaction.

[0021] In the above preparation method, the catalyst is a soluble transition metal salt;

[0022] Preferably, the catalyst is one or more of a mixture of copper salt, iron salt, cobalt salt, nickel salt, silver salt, palladium salt.

[0023] In some embodiments, the anion of the metal salt of the catalyst is selected from nitrate, sulfate, chloride, and the like.

[0024] In the above preparation method, the free radical initiator is one or more of a combination of air, oxygen, peroxide free radical initiator, azo free radical initiator.

[0025] In the above preparation method, the peroxide free radical initiator is an organic peroxide initiator and / or an inorganic peroxide initiator.

[0026] The organic peroxide initiator is one or more of a combination of benzoyl peroxide, t-butyl benzoyl peroxide, methyl ethyl ketone peroxide.

[0027] The inorganic peroxide initiator is one or more of a combination of hydrogen peroxide, ammonium persulfate, potassium persulfate.

[0028] The azo free radical initiator is one or more of a combination of azobisisobutyronitrile, azobisisobutyronitrile dihydrochloride, azobisisoheptyl nitrile.

[0029] In the above preparation method, the molar ratio of propargyl alcohol, alkali metal sulfite and / or alkali metal bisulfite is 1:0.5-10, preferably the molar ratio of propargyl alcohol, alkali metal sulfite and / or alkali metal bisulfite is 1:0.5-5.

[0030] In some embodiments of the present application, the molar ratio of propargyl alcohol, alkali metal sulfite and / or alkali metal bisulfite is 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0031] In the above preparation method, the catalyst is 0.1-10 wt% of the mass of propargyl alcohol.

[0032] In some embodiments of the present application, the catalyst is 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.7 wt%, 0.9 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt% of the mass of propargyl alcohol.

[0033] In the above preparation method, the free radical initiator is 1-20 wt% of the mass of propargyl alcohol.

[0034] In some embodiments of the present application, the radical initiator is 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt% of the mass of propargyl alcohol.

[0035] In the above preparation method, in step 1, the raw material exists in the form of an aqueous solution, and the catalyst, the radical initiator, and the raw material are each independently added to the reaction container in any one of the following ways: one-time addition, dropwise addition, and batch addition, and then the reaction is carried out; preferably, the catalyst, the radical initiator, and the raw material are each independently added dropwise, which is beneficial to improving the reaction conversion rate and reducing the occurrence of side reactions.

[0036] The reaction time of step 1 is 30 min to 2 h.

[0037] The reaction temperature of step 1 is 30-100°C.

[0038] Optionally, the reaction time is 30 min, 40 min, 50 min, 1 h, 70 min, 80 min, 90 min, 1.5 h, 100 min, 110 min, or 2 h.

[0039] Optionally, the reaction temperature is 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C.

[0040] In the above preparation method, step 2 is specifically as follows:

[0041] Step 21: removing part or all of the water in the addition product;

[0042] Step 22: adjusting the pH value of the mixture obtained in step 21 to 4 or below;

[0043] Step 23: separating the acidified product from the mixture obtained in step 22.

[0044] In actual application, step 21 preferably removes the water in the addition product by distillation under normal pressure or reduced pressure; the degree of distillation is controlled by controlling the volume of the distilled liquid, so that the amount of distillation is 40-90% of the volume of the liquid after neutralization.

[0045] In step 22, the pH of the mixture can be controlled by an organic acid or an inorganic acid, and the pH is more preferably controlled to be below 2; preferably, 98% sulfuric acid is used, which has high acidification efficiency and does not introduce impurity elements such as chlorine, which is beneficial to reducing the difficulty of separation and purification and effectively improving the purity of the product.

[0046] The addition product is subjected to pH regulation to achieve salt extrusion, i.e. to separate the alkali metal ion from the 1-sulfonate-1-propenol to form 3-hydroxypropene sulfonic acid and inorganic salt, which can be separated by various separation operations;

[0047] The separation operation in step 23 can be column chromatography separation, and the mobile phase is ethyl acetate:methanol=1:1 to obtain a solution of 3-hydroxypropene sulfonic acid, and 3-hydroxypropene sulfonic acid is obtained after evaporation of the solvent. 3-hydroxypropene sulfonic acid can also be separated by vacuum distillation.

[0048] In the above preparation method, the reaction temperature of step 3 is 130-160℃; the optional reaction temperature is 130℃, 140℃, 150℃ or 160℃.

[0049] The reaction equation of the preparation method of the present application is as follows:

[0050] Addition reaction:

[0051]

[0052] Acidification reaction:

[0053]

[0054] Cyclization reaction:

[0055]

[0056] M is an alkali metal ion.

[0057] The above technical solution of the present application has at least one of the following advantages or beneficial effects:

[0058] The present application selects more inexpensive propargyl alcohol and alkali metal sulfite and / or alkali metal bisulfite as raw materials, and uses metal salt and free radical initiator, and the catalyst in the form of soluble metal salt can also be considered as an oxidation-reduction initiator. Specifically, propargyl alcohol is a typical terminal alkyne, and its steric hindrance is smaller than that of non-terminal alkyne. Transition metal salt can effectively catalyze the free radical reaction to realize the addition of alkyne. Meanwhile, in the sodium bisulfite system, the free radicals formed by the initiator can couple with the free radicals of copper alkynyl to form a unique sp bond, realizing the direct sulfonation of terminal alkyne and effectively improving the conversion of the addition reaction, thereby effectively solving the problems of slow reaction rate and low sulfonation conversion rate in the sulfonation of propargyl alcohol.

[0059] The present application uses a mixed system of metal salt and initiator to efficiently catalyze the addition reaction in the PST synthesis reaction, and the target product can be obtained in a short time with high raw material conversion rate.

[0060] Meanwhile, the present invention uses metal salt catalysts and free radical initiators to ensure a forward and rapid reaction. These two reagents are inexpensive and can effectively reduce the production cost of 1-propene-1,3-sulfonyl lactone. Attached Figure Description

[0061] Figure 1 The PST 1H NMR spectrum of 1-propylene-1,3-sulfonyl lactone from Example 1 of the present invention is shown. Detailed Implementation

[0062] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0063] Example 1

[0064] Step 1:

[0065] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0066] Dissolve 15.6 g (0.15 mol) sodium bisulfite and 6.3 g (0.05 mol) sodium sulfite in 60 g of water to prepare solution B;

[0067] 0.86 g of tert-butyl hydrogen peroxide was placed in a dropping funnel to prepare solution C;

[0068] Dissolve 6.3g sodium sulfite (0.05mol) and 0.1g copper sulfate in 25g water to prepare a reaction solution, place it in a three-necked flask, heat to 40℃, and simultaneously add solutions A, B, and C dropwise to the reaction solution over a period of 1 hour.

[0069] By optimizing the feeding method, sodium sulfite is added to the reactor solution and heated to increase the pH of the reactor solution, creating an alkaline environment for the addition reaction and improving the degree of addition reaction. Furthermore, by heating the reactor solution and simultaneously adding solutions A, B, and C dropwise, the conversion rate of propargyl alcohol is further improved. Compared to adding propargyl alcohol dropwise to sodium sulfite and / or sodium bisulfite solution separately, the feeding method described in this embodiment avoids insufficient propargyl alcohol content in the reaction system, which could lead to the breakage of double bonds in the product and subsequent reaction with bisulfite ions to generate single-bonded disulfite byproducts. Simultaneously, compared to using propargyl alcohol as the reactor solution and adding sodium sulfite and / or bisulfite, free radical initiators, etc., the feeding method avoids propargyl alcohol undergoing self-polymerization in the presence of the initiator, thus preventing the generation of polymerization byproducts.

[0070] Step 2: After the addition reaction is completed, the solution is distilled under reduced pressure of 5 kPa for 1 hour to remove 90% of the water to avoid affecting the subsequent acidification effect; then sulfuric acid (98%) is added until the solution pH ≤ 4 for acidification. The precipitated sodium sulfate in the acidified reaction solution can be separated by filtration; the yield of 3-hydroxypropenesulfonic acid is detected by gas phase, and the results are shown in Table 1.

[0071] Step 3: Heating to 140℃ for cyclization and dehydration for 1 hour, followed by vacuum separation to obtain the product 1-propene-1,3-sulfonyl lactone. The PST 1H NMR spectrum of 1-propene-1,3-sulfonyl lactone can be found in [reference needed]. Figure 1 .

[0072] Example 2

[0073] The process is largely the same as in Example 1, except that the amount of copper sulfate and tert-butyl hydroperoxide is adjusted to 0.0084 g, the dropping time is 30 min, the reaction temperature in step 1 is 60 °C, the acidification pH in step 2 is approximately 3, and the reaction temperature in step 3 is 130 °C with a dehydration time of 2 h.

[0074] Example 3

[0075] The process is largely the same as in Example 1, except that the amount of copper sulfate is adjusted to 0.84 g, the amount of tert-butyl hydroperoxide is adjusted to 1.68 g, the dropping time is 2 h, the reaction temperature in step 1 is 100 °C, the acidification pH in step 2 is approximately 2, and the reaction temperature in step 3 is 160 °C with a dehydration time of 3 h.

[0076] Example 4

[0077] The method is largely the same as in Example 1, except that copper sulfate is replaced by an equal weight of copper nitrate, and tert-butyl hydroperoxide is replaced by an equal weight of azobisisobutyl diimide hydrochloride.

[0078] Example 5

[0079] The method is largely the same as in Example 2, except that copper sulfate is replaced by an equal weight of cuprous bromide, and tert-butyl hydroperoxide is replaced by an equal weight of potassium persulfate.

[0080] Example 6

[0081] The method is largely the same as in Example 3, except that copper sulfate is replaced by an equal weight of palladium chloride, and tert-butyl hydroperoxide is replaced by an equal weight of ammonium persulfate.

[0082] Example 7

[0083] The method is largely the same as in Example 1, except that copper sulfate is replaced by an equal weight of silver chloride, and tert-butyl hydroperoxide is replaced by an equal weight of benzoyl peroxide.

[0084] Example 8

[0085] Step 1:

[0086] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0087] Dissolve 15.6 g (0.15 mol) of sodium bisulfite in 60 g of water to prepare solution B;

[0088] 0.86 g of tert-butyl hydrogen peroxide was placed in a dropping funnel to prepare solution C;

[0089] Dissolve 0.1g of copper sulfate in 25g of water to prepare a reaction solution, place it in a three-necked flask, heat it to 40℃, and simultaneously add solutions A, B, and C dropwise into the reaction solution over a period of 1 hour.

[0090] Step 2: After the addition reaction is completed, distill under reduced pressure to remove most of the water, then add sulfuric acid to acidify the solution until the pH is ≤4, and continue to concentrate the resulting reaction solution under reduced pressure.

[0091] Step 3: Heat to 140℃ for cyclization and dehydration for 1 hour, and then separate under reduced pressure to obtain the product 1-propylene-1,3-sulfonyl lactone.

[0092] Example 9

[0093] Step 1:

[0094] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0095] Dissolve 62.4 g (0.6 mol) of sodium bisulfite in 220 g of water to prepare solution B;

[0096] 0.86 g of tert-butyl hydrogen peroxide was placed in a dropping funnel to prepare solution C;

[0097] Dissolve 0.1g of copper sulfate in 25g of water to prepare a reaction solution, place it in a three-necked flask, heat it to 40℃, and simultaneously add solutions A, B, and C dropwise into the reaction solution over a period of 1 hour.

[0098] Step 2: After the addition reaction is completed, distill under reduced pressure to remove most of the water, then add sulfuric acid to acidify the solution until the pH is ≤4, and continue to concentrate the resulting reaction solution under reduced pressure.

[0099] Step 3: Heat to 140℃ for cyclization and dehydration for 1 hour, and then separate under reduced pressure to obtain the product 1-propylene-1,3-sulfonyl lactone.

[0100] Example 10

[0101] Step 1:

[0102] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0103] Dissolve 72.8 g (0.7 mol) sodium bisulfite and 50.4 g (0.4 mol) sodium sulfite in 240 g of water to prepare solution B;

[0104] 0.86 g of tert-butyl hydrogen peroxide was placed in a dropping funnel to prepare solution C;

[0105] Dissolve 50.4g (0.4mol) sodium sulfite and 0.1g copper sulfate in 25g water to prepare a reaction solution, place it in a three-necked flask, heat to 40℃, and simultaneously add solutions A, B, and C dropwise to the reaction solution over a period of 1 hour.

[0106] Step 2: After the addition reaction is completed, distill under reduced pressure to remove most of the water, then add sulfuric acid to acidify the solution until the pH is ≤4, and continue to concentrate the resulting reaction solution under reduced pressure.

[0107] Step 3: Heat to 140℃ for cyclization and dehydration for 1 hour, and then separate under reduced pressure to obtain the product 1-propylene-1,3-sulfonyl lactone.

[0108] Example 11

[0109] Step 1:

[0110] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0111] Dissolve 15.6 g (0.15 mol) sodium bisulfite and 6.3 g (0.05 mol) sodium sulfite in 60 g of water to prepare solution B;

[0112] 0.86 g of tert-butyl hydrogen peroxide was placed in a dropping funnel to prepare solution C;

[0113] Dissolve 6.3g sodium sulfite (0.05mol) and 0.1g copper sulfate in 25g water to prepare a reaction solution, place it in a three-necked flask, heat to 40℃, and add solutions A, B and C to the reaction solution at once. The reaction time is 1h.

[0114] Step 2: After the addition reaction is completed, distill under reduced pressure to remove most of the water, then add sulfuric acid to acidify the solution until the pH is ≤ 4, and then concentrate the resulting reaction solution under reduced pressure.

[0115] Step 3: Heat to 140℃ for cyclization and dehydration for 1 hour, and then separate under reduced pressure to obtain the product 1-propylene-1,3-sulfonyl lactone.

[0116] Example 12

[0117] Step 1:

[0118] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0119] Dissolve 7.8 g (0.075 mol) of sodium bisulfite in 60 g of water to prepare solution B;

[0120] 0.86 g of tert-butyl hydrogen peroxide was placed in a dropping funnel to prepare solution C;

[0121] Dissolve 0.1g of copper sulfate in 25g of water to prepare a reaction solution, place it in a three-necked flask, heat it to 40℃, and simultaneously add solutions A, B, and C dropwise into the reaction solution over a period of 1 hour.

[0122] Step 2: After the addition reaction is completed, distill under reduced pressure to remove most of the water, then add sulfuric acid to acidify the solution until the pH is ≤4, and continue to concentrate the resulting reaction solution under reduced pressure.

[0123] Step 3: Heat to 140℃ for cyclization and dehydration for 1 hour, and then separate under reduced pressure to obtain the product 1-propylene-1,3-sulfonyl lactone.

[0124] Comparative Example 1

[0125] Step 1:

[0126] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0127] Dissolve 15.6 g (0.15 mol) sodium bisulfite and 6.3 g (0.05 mol) sodium sulfite in 60 g of water to prepare solution B;

[0128] Dissolve 6.3g sodium sulfite (0.05mol) and 0.1g copper sulfate in 25g water to prepare a reaction solution, place it in a three-necked flask, heat to 40℃, and simultaneously add solution A and solution B dropwise into the reaction solution over a period of 1 hour.

[0129] Step 2: After the addition reaction is completed, distill under reduced pressure to remove most of the water, then add sulfuric acid to acidify the solution until the pH is ≤4, and continue to concentrate the resulting reaction solution under reduced pressure.

[0130] Step 3: Heat to 140℃ for cyclization and dehydration for 1 hour, and then separate under reduced pressure to obtain the product 1-propylene-1,3-sulfonyl lactone.

[0131] Comparative Example 2

[0132] Step 1:

[0133] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0134] Dissolve 15.6 g (0.15 mol) sodium bisulfite and 6.3 g (0.05 mol) sodium sulfite in 60 g of water to prepare solution B;

[0135] 0.86 g of tert-butyl hydrogen peroxide was placed in a dropping funnel to prepare solution C;

[0136] Dissolve 6.3g of sodium sulfite (0.05mol) in 25g of water to prepare a reaction solution, place it in a three-necked flask, heat to 40℃, and simultaneously add solutions A, B, and C dropwise to the reaction solution over a period of 1 hour.

[0137] Step 2: After the addition reaction is completed, distill under reduced pressure to remove most of the water, then add sulfuric acid to acidify the solution until the pH is ≤4, and continue to concentrate the resulting reaction solution under reduced pressure.

[0138] Step 3: Heat to 140℃ for cyclization and dehydration for 1 hour, and then separate under reduced pressure to obtain the product 1-propylene-1,3-sulfonyl lactone.

[0139] Comparative Example 3

[0140] Step 1:

[0141] Dissolve 8.4 g (0.15 mol) of propargyl alcohol in 15 g of water to prepare solution A;

[0142] Dissolve 15.6 g (0.15 mol) sodium bisulfite and 6.3 g (0.05 mol) sodium sulfite in 60 g of water to prepare solution B;

[0143] 0.001 g of tert-butyl hydroperoxide was placed in a dropping funnel to prepare solution C;

[0144] Dissolve 6.3g sodium sulfite (0.05mol) and 0.1g copper sulfate in 25g water to prepare a reaction solution, place it in a three-necked flask, heat to 40℃, and simultaneously add solutions A, B, and C dropwise to the reaction solution over a period of 1 hour.

[0145] Step 2: After the addition reaction is completed, distill under reduced pressure to remove most of the water, then add sulfuric acid to acidify the solution until the pH is ≤4, and continue to concentrate the resulting reaction solution under reduced pressure.

[0146] Step 3: Heat to 140℃ for cyclization and dehydration for 1 hour, and then separate under reduced pressure to obtain the product 1-propylene-1,3-sulfonyl lactone.

[0147] Results Statistics

[0148] The weight of 3-hydroxypropenesulfonic acid obtained from the concentration in step 2 was measured in each case to calculate the addition yield, and the weight of 1-propene-1,3-sulfonyl lactone obtained in step 3 was measured to calculate the total yield. At the same time, the purity of 1-propene-1,3-sulfonyl lactone in the product of step 3 was determined.

[0149] The addition yield and total yield of this invention are calculated using the product obtained from the complete reaction of propargyl alcohol as the calculation standard; in Example 12, the product obtained from the complete reaction of 0.075 mol of propargyl alcohol is used as the calculation standard.

[0150] The test results are shown in Table 1 below;

[0151] Table 1 Statistical Table of Results

[0152]

[0153]

[0154]

[0155] Results analysis:

[0156] 1. The experimental results of Examples 1-3 show that as the amount of catalyst and initiator increases, both the addition yield and the total yield increase;

[0157] 2. As can be seen from Examples 4 to 7, when different types of catalysts and initiators are used, there will be certain differences in the addition yield and total yield. Since the initiators in Examples 5 and 6 are similar, the results of Examples 5 and 6 are significantly different, indicating that the catalytic effect of palladium chloride is better than that of copper ions and better than that of cuprous ions.

[0158] 3. In Examples 8 and 9, which used only bisulfite, the addition yield and total yield decreased, indicating that in the addition reaction, it is preferable to use a combination of alkali metal sulfite and alkali metal bisulfite.

[0159] 4. The addition yield and total yield of Example 10 were further improved, while the addition yield and total yield of Example 12 were significantly reduced. This indicates that in the addition reaction, the excess of alkali metal sulfite and / or alkali metal bisulfite should be controlled. Based on the extent of improvement, we believe that it is appropriate to control the total amount of alkali metal sulfite and / or alkali metal bisulfite to be 1 to 2 times the molar amount of propargyl alcohol, which takes into account both efficiency and material cost.

[0160] 5. Example 11 uses a one-pot reaction, which slightly reduces the addition yield and total yield. However, from the perspectives of process complexity, economy and efficiency, it is recommended to use the dropwise addition method for industrial production.

[0161] 6. As can be seen from Comparative Examples 1 and 2, neither soluble metal salts nor free radical initiators alone can achieve good addition yields or total yields; however, as shown in Example 1, the yield is significantly improved when the two are effectively combined, which is the greatest innovation of this invention.

[0162] 7. As can be seen from Comparative Example 3, when the amount of free radical initiator is too small, it does not improve the addition yield or the total yield. This shows that the free radical initiator of the present invention plays the role of an initiator in the present invention.

Claims

1. A method for preparing 1-propylene-1,3-sulfonyl lactone, characterized in that, Includes the following steps: Step 1: Addition reaction, using propargyl alcohol and alkali metal sulfites and / or alkali metal bisulfites as raw materials, an addition reaction is carried out in the presence of a catalyst and a free radical initiator to obtain the addition product; Step 2: Acidification reaction, adjust the pH of the addition product to 4 or below, and separate the acidified product; Step 3: Cyclization reaction. The acidified product is subjected to a cyclization reaction to obtain 1-propene-1,3-sulfonyl lactone. The catalyst is a soluble metal salt that is soluble in water.

2. The preparation method according to claim 1, characterized in that, The catalyst is a soluble transition metal salt; Preferably, the catalyst is one or a mixture of copper salt, iron salt, cobalt salt, nickel salt, silver salt, and palladium salt.

3. The preparation method according to claim 1, characterized in that, The free radical initiator is one or more combinations of air, oxygen, peroxide free radical initiators, and azo free radical initiators.

4. The preparation method according to claim 3, characterized in that, The peroxide-based free radical initiator is an organic peroxide initiator and / or an inorganic peroxide initiator; The organic peroxide initiator is one or more combinations of benzoyl peroxide, benzoyl tert-butyl peroxide, and methyl ethyl ketone peroxide; The inorganic peroxide initiator is one or more of hydrogen peroxide, ammonium persulfate, and potassium persulfate; The azo radical initiator is one or more combinations of azobisisobutyronitrile, azobisisobutylimide hydrochloride, and azobisisoheptanenitrile.

5. The preparation method according to claim 1, characterized in that, The molar ratio of propargyl alcohol to alkali metal sulfite and / or alkali metal bisulfite is 1:0.5 to 10, preferably, the molar ratio of propargyl alcohol to alkali metal sulfite and / or alkali metal bisulfite is 1:0.5 to 5.

6. The preparation method according to claim 1, characterized in that, The catalyst is 0.1 to 10 wt% of propargyl alcohol.

7. The preparation method according to claim 1, characterized in that, The free radical initiator is 1-20 wt% of propargyl alcohol.

8. The preparation method according to claim 1, characterized in that, In step 1, the raw material exists in the form of an aqueous solution, and the catalyst, free radical initiator, and raw material are added to the reaction vessel independently in any one way, by adding at once, adding dropwise, or adding in batches to carry out the reaction. The reaction time for step 1 is 30 min to 2 h. The reaction temperature in step 1 is 30–100°C.

9. The preparation method according to claim 1, characterized in that, Step 2 specifically involves: Step 21: Remove some or all of the water from the addition product; Step 22: Adjust the pH of the mixture obtained in Step 21 to below 4; Step 23: Separate the acidification product from the mixture obtained in step 22.

10. The preparation method according to claim 1, characterized in that, The reaction temperature in step 3 is 130–160°C.

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