CN112028740B - Process for producing chlorohydrin - Google Patents
Process for producing chlorohydrin Download PDFInfo
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- CN112028740B CN112028740B CN202010964970.9A CN202010964970A CN112028740B CN 112028740 B CN112028740 B CN 112028740B CN 202010964970 A CN202010964970 A CN 202010964970A CN 112028740 B CN112028740 B CN 112028740B
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/64—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by simultaneous introduction of -OH groups and halogens
Abstract
The invention relates to the field of organic synthesis, and discloses a method for preparing chlorohydrin, which comprises the following steps: in the presence of an organic solvent and water, N-chloroisocyanuric acid and/or a salt thereof and a pH regulator are added to isoprene to perform a chlorohydrination reaction at such a rate that the difference between the maximum value and the minimum value of the pH of the reaction system is not higher than 1, preferably not higher than 0.5. The method has the advantages of stable reaction process, less by-products and high product yield.
Description
Technical Field
The invention relates to the field of organic synthesis, in particular to a preparation method of chlorohydrin.
Background
Vitamin a acetate is an important pharmaceutical and nutraceutical, with the following structure:
at present, two synthesis routes are commonly used in the field of vitamin A production, one is a C14 and C6 method:
the other method is C15 plus C5:
the two methods have respective advantages and disadvantages because the C14 and the C6 relate to more materials, long route, complex equipment and large fixed investment. Therefore, the method of C15 plus C5 is becoming more popular.
The synthesis of five-carbon aldehyde (C5) mainly comprises two types, one is prepared by taking butenediol as a raw material through esterification, rearrangement and hydroformylation:
the method has less byproducts and less environmental pollution, but the hydroformylation has one step at high temperature and high pressure and uses expensive rhodium catalyst.
Another way to synthesize the pentanal is to carry out chlorohydrination, esterification and oxidation on isoprene as a raw material to obtain the pentanal:
the method has the advantages of mild reaction conditions, convenient operation, cheap and easily-obtained raw materials and auxiliary materials, and has been widely concerned by people.
CN101041619A discloses a preparation method of 1-chloro-2-methyl-4-hydroxy acyloxy-2-butene, which comprises the following steps: isoprene is taken as a raw material, calcium hypochlorite solid and a pH value regulator acetic acid are added to carry out chlorohydrination reaction in the presence of a solvent, and addition products of 1,2 sites and 1,4 sites are respectively obtained. The method has the advantages of more chlorohydrin byproducts, lower yield, complex components in the generated wastewater, high difficulty in environmental protection treatment and high cost.
CN100410230C discloses a preparation method of a vitamin A derivative intermediate 1-chloro-2-methyl-4-hydroxy acyloxy-2-butene, which specifically comprises the following steps: (1) carrying out chlorohydrination reaction on isoprene serving as a raw material in a reaction system formed by N-chloroisocyanuric acid series compounds and water to respectively obtain 1-chloro-2-hydroxy-2-methyl-3-butene and 1-chloro-2-methyl-4-hydroxy-2-butene which are addition products of 1,2 bits and 1,4 bits; (2) the reaction mixture reacts with acid anhydride or acyl chloride under the catalysis of acid to obtain the 1-chloro-2-methyl-4-hydroxy acyloxy-2-butene. The method has the advantages of more byproducts, lower chlorohydrin yield and difficult process control.
In view of the above, the conventional chlorohydrination reaction has a problem of low reaction yield, and a method for preparing chlorohydrin with high yield is required.
Disclosure of Invention
In view of the above problems in the prior art, the present invention is directed to a method for preparing chlorohydrin, which has the advantages of stable reaction process and high product yield.
The inventors of the present invention found that the chlorohydrination reaction of isoprene is greatly affected by different pH values, and further studied how to obtain a higher reaction yield by controlling the pH value of the reaction system. Based on this, the present invention provides a method for preparing chlorohydrin, which comprises the steps of: in the presence of an organic solvent and water, N-chloroisocyanuric acid and/or a salt thereof and a pH regulator are added to isoprene to perform a chlorohydrination reaction at such a rate that the difference between the maximum value and the minimum value of the pH of the reaction system is not higher than 1, preferably not higher than 0.5.
According to the method provided by the invention, the N-chloroisocyanuric acid and/or the salt thereof and the pH regulator are simultaneously added into the reaction system, so that the real-time precise control of the pH value and the reaction temperature can be realized, the generation of byproducts is well inhibited, the chlorohydrination reaction can be smoothly carried out, and the higher product yield is obtained.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The present invention provides a method for preparing chlorohydrin, which comprises the following steps: in the presence of an organic solvent and water, N-chloroisocyanuric acid and/or a salt thereof and a pH regulator are added to isoprene to perform a chlorohydrination reaction at such a rate that the difference between the maximum value and the minimum value of the pH of the reaction system is not higher than 1, preferably not higher than 0.5.
In the present invention, the chlorohydrination reaction may be carried out in a reaction flask equipped with a thermometer and a stirring device, and the reaction flask may be provided with 1 or more feed ports, preferably 2 or more feed ports.
According to the method of the present invention, the volume ratio of the organic solvent to water may be 1 (0.1-5), preferably 1 (0.1-2).
In the invention, in the chlorohydrination reaction process, water is added to participate in the chlorohydrination reaction on one hand, and on the other hand, the chlorination reagent (N-chloroisocyanuric acid and/or salt thereof) can be better dissolved in the reaction system.
According to the process of the present invention, the total amount of the organic solvent and water is not particularly limited as long as the requirements of the chlorohydrination reaction can be satisfied, and preferably the total amount of the organic solvent and water per gram of isoprene may be 1 to 20mL, more preferably 4 to 15 mL.
According to the method of the present invention, the organic solvent may be selected from at least one of acetone, methanol and methyl isobutyl ketone, preferably acetone.
According to the method of the present invention, the N-chloroisocyanuric acid and/or salts thereof may be selected from existing substances capable of reacting with isoprene to form chlorohydrin, and preferably, the N-chloroisocyanuric acid may be selected from trichloroisocyanuric acid or dichloroisocyanuric acid.
According to the process of the present invention, the salt of N-chloroisocyanuric acid may be selected from at least one of sodium dichloroisocyanurate, potassium dichloroisocyanurate, calcium dichloroisocyanurate and magnesium dichloroisocyanurate.
According to the method of the present invention, the pH adjusting agent may be obtained by dissolving a salt which is basic in solution after dissolving in water, and preferably, the pH adjusting agent may be at least one selected from the group consisting of an aqueous solution of sodium bicarbonate, an aqueous solution of potassium bicarbonate, an aqueous solution of sodium carbonate, an aqueous solution of sodium acetate, and an aqueous solution of potassium carbonate, and more preferably, an aqueous solution of sodium bicarbonate.
According to the method of the present invention, the mass fraction of the solute in the pH adjuster may be 1 to 15 wt%, preferably 1 to 9 wt%.
According to the process of the invention, the molar ratio of the N-chloroisocyanuric acid and/or salts thereof to isoprene may be (0.1-1): 1, preferably (0.33-0.5): 1.
in the present invention, the molar amount of N-chloroisocyanuric acid and/or a salt thereof is measured as a ratio of the weight of N-chloroisocyanuric acid and/or a salt thereof to the relative molecular mass thereof.
According to the method of the present invention, in order to more effectively suppress the production of by-products in the chlorohydrination reaction, the pH of the chlorohydrination reaction system is preferably controlled within a certain range, and preferably, the pH of the chlorohydrination reaction system is preferably 5 to 8, more preferably 6 to 6.5.
According to the method of the present invention, preferably, the method comprises: adding the solution of the N-chloroisocyanuric acid and/or the salt thereof and a pH regulator into a mixed solution containing isoprene, an organic solvent and water for reaction, wherein the adding speed of the solution of the N-chloroisocyanuric acid and/or the salt thereof and the pH regulator is such that the pH of the reaction system is maintained within the range of 5-8 and the difference between the maximum value and the minimum value is not higher than 1, preferably not higher than 0.5, and then continuing the reaction for 0.5-2 h.
In the present invention, preferably, the solution of N-chloroisocyanuric acid and/or its salt may be at least one selected from trichloroisocyanuric acid solution, dichloroisocyanuric acid solution, sodium dichloroisocyanurate solution, potassium dichloroisocyanurate solution, calcium dichloroisocyanurate solution and magnesium dichloroisocyanurate solution, and the molar concentration thereof may be 0.5 to 2 mol/L; in general, the solution of N-chloroisocyanuric acid and/or its salt is obtained by dissolving N-chloroisocyanuric acid and/or its salt in a dissolving solvent, preferably, the dissolving solvent can be acetone or methanol, more preferably acetone.
In the present invention, preferably, the pH adjuster is an aqueous solution of sodium bicarbonate, an aqueous solution of potassium bicarbonate, an aqueous solution of sodium carbonate, an aqueous solution of sodium acetate, and an aqueous solution of potassium carbonate, and the mass fraction of the solute thereof may be 1 to 20 wt%.
In the present invention, the content of isoprene in the mixed solution containing isoprene, organic solvent and water may be 0.05 to 0.5g/mL, preferably 0.1 to 0.3 g/mL. In the present invention, since the mixed solution may contain a small amount of an alkaline substance, the aqueous phase extracted after the completion of the reaction can be reused as the mixed solution.
In the invention, the detection of the pH value in the chlorohydrination reaction process can be carried out by using a pH meter or a precise pH test paper.
According to the process of the invention, the temperature of the chlorohydrination reaction is preferably from-10 ℃ to 30 ℃, more preferably from-5 ℃ to 5 ℃; the time of the chlorohydrination reaction is preferably 1 to 5 hours, more preferably 1 to 3 hours.
According to the process of the invention, the chlorohydrination reaction may be carried out in the presence of a polymerization inhibitor and/or a phase transfer catalyst. The polymerization inhibitor can further improve the yield of chlorohydrination reaction and inhibit the polymerization of isoprene; the phase transfer catalyst can further promote the contact of oil and water phases.
According to the method of the present invention, the polymerization inhibitor may be preferably at least one selected from hydroquinone, 2, 6-di-tert-butyl-p-toluidine, p-hydroxyanisole and p-benzoquinone, and more preferably, the polymerization inhibitor is hydroquinone.
According to the method of the present invention, preferably, the phase transfer catalyst may be one selected from the group consisting of tetrabutylammonium bromide, tetrabutylammonium chloride and benzyltriethylammonium chloride, and more preferably, the phase transfer catalyst is benzyltriethylammonium chloride.
According to the method of the present invention, the amount of the polymerization inhibitor to be used is not particularly limited as long as the requirements of the chlorohydrination reaction of the present invention can be satisfied, and preferably, the amount of the polymerization inhibitor to be used may be 0.05 to 5 moles, more preferably 0.1 to 1 mole per 100 moles of isoprene.
According to the process of the present invention, generally, there is no particular requirement for the amount of the phase transfer catalyst to be used as long as the requirements of the chlorohydrination reaction of the present invention can be satisfied, and preferably, the amount of the phase transfer catalyst to be used may be 0.05 to 2 moles, more preferably 0.1 to 1 mole, per 100 moles of isoprene.
According to the process of the invention, the chlorohydrination reaction product may also be subjected to a work-up to obtain a purer chlorohydrin, said work-up preferably comprising filtration, extraction, distillation operations. Wherein, the distilled organic solvent, the unreacted isoprene and the water phase of the extraction operation can be recycled for chlorohydrination reaction.
In the invention, preferably, the chlorohydrination reaction product can be separated and purified by vacuum rectification under the conditions of a packed column of 300-800mm, the temperature of 50-70 ℃ and the vacuum degree of 3-7 bar.
In the present invention, the by-product can be obtained by distillation under the conditions comprising: the temperature is 40-50 ℃, the vacuum degree is 3-7bar, and the packed column is 200-500 mm.
In the present invention, the yield of the by-product can be further calculated by iodination, for example, a crude product containing the by-product can be reacted with an excess amount of sodium iodide to obtain an iodide corresponding to the by-product, which is separated and purified, and then converted into the yield of the by-product.
In the present invention, the chlorohydrin may be a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol.
In the present invention, the by-product may be 2-chloromethyl-1, 3-butadiene.
The present invention will be described in detail below by way of examples.
The raw materials, solvents, catalysts, and the like used in the following examples and comparative examples were obtained commercially. The content of the product was detected by Gas Chromatography (GC), and the yield was calculated from the molar amount of the actually obtained product/the molar amount of the actually reacted isoprene × 100%. The drying temperature is 50 ℃ and the drying time is 8 h.
GC analysis conditions were as follows: chromatography column SE-30 x 30m 0.32mm 0.33 μm; a sample inlet is 300 ℃; the split ratio is 10: 1; column pressure 128.9 KPa; the total flow rate is 64.3 mL/min; a detector is 300 ℃; the column temperature is 40 ℃ for 2min,20 ℃/min and 260 ℃ for 15 min.
Example 1
A2000 mL four-necked flask equipped with a thermometer and a stirring device was placed in an alcohol cooling bath, and isoprene (80g,1.176mol), acetone (300g) and water (240g) were added, followed by 0.6g hydroquinone and 0.5g benzyltriethylammonium chloride. Trichloroisocyanuric acid (95.7g,0.412mol, 90% of available chlorine content) is dissolved in acetone (360g) to prepare an acetone solution of trichloroisocyanuric acid. Keeping the temperature of the reaction system at 0 ℃ under stirring, dripping acetone solution of trichloroisocyanuric acid from one feed inlet, dripping sodium bicarbonate solution with 6 mass percent of solute from the other feed inlet, keeping the dripping at the same time, controlling the pH of the reaction system between 6 and 6.2, finishing the dripping within about 1.5 hours, and then continuing the heat preservation reaction for 1 hour. The reaction was monitored by gas chromatography for the total amount of sodium bicarbonate solution 9 mL. Filtering, washing filter cake with 40mL of water and 40mL of acetone, discarding the filter cake, collecting the filtrate, combining the filtrates, and distilling under reduced pressure at a temperature lower than 40 ℃ to recover acetone and 2g of unreacted isoprene, which can be used for the next reaction. Cyclohexane (40mL multiplied by 3) is added into the distillation residual liquid for extraction, the extracted layered water layer is 262g which can be used for the next reaction, the organic layer is decompressed and distilled at 40 ℃ to recover the solvent, and then the mixture of the product 1-chloro-2-methyl-3-butylene-2-alcohol and 4-chloro-3-methyl-2-butylene-1-alcohol is obtained, the gas chromatography analysis shows that the total content of the product is 96 weight percent, and the yield is 97 percent. Separating the mixture by vacuum rectification with a packed column (500mm) at 60 deg.C and 5bar vacuum degree, and performing structural identification.
Determination of the content of the by-product 2-chloromethyl-1, 3-butadiene: and (2) carrying out vacuum rectification on the recovered acetone solution by using a packed column, collecting 5.6g of a crude product of 2-chloromethyl-1, 3-butadiene under the conditions of the temperature of 45 ℃ and the vacuum degree of 5bar and the addition of the packed column (300mm), adding 40mL of dichloromethane into the crude product, then adding 12g of sodium iodide, stirring and carrying out heat preservation reaction for 5h at the temperature of 25 ℃, then directly adding silica gel (30g, 200 meshes and 300 meshes) for sample mixing, removing the solvent by using a rotary evaporator, loading the residual liquid on the column, carrying out elution and separation by using an eluent (ethyl acetate: petroleum ether ═ 20:1), and concentrating and drying the eluent to obtain 5.3g of iodide-derived 2-iodomethyl-1, 3-butadiene. After conversion, 3g of 2-chloromethyl-1, 3-butadiene by-product was obtained with a yield of 2.3%.
And (3) product structure confirmation: 1-chloro-2-methyl-3-buten-2-ol:1H-NMR(CDCl3)δ：1.10(S,3H),3.55(dd,2H),5.29(dd,2H),6.0(dd, 1H); 4-chloro-3-methyl-2-buten-1-ol:1H-NMR(CDCl3)δ：1.70(s,3H),4.05(s,2H),4.15(d,2H),5.65(dd,1H)。
GC analysis results: 1-chloro-2-methyl-3-buten-2-ol: the peak retention time is 3.8min, and the content: 52 wt%; 4-chloro-3-methyl-2-buten-1-ol: the peak retention time was 6.0min and 6.3min, respectively, and the content was 2 wt% and 38 wt%, respectively.
The by-product was derived from iodide to confirm that (2-iodomethyl-1, 3-butadiene):1H-NMR(CDCl3)δ：4.03(s,2H),5.25(dd,2H),5.42(dd,2H),6.32(dd,1H)。
GC analysis results: the peak-emerging retention time of 2-chloromethyl-1, 3-butadiene was 2.8min, the content was 5.6 wt.%, and the GC retention time of 2-iodomethyl-1, 3-butadiene was 5.3 min.
Example 2
A2000 mL four-necked flask equipped with a thermometer and a stirring device was placed in an alcohol cooling bath, and isoprene (80g,1.176mol), acetone (300g) and water (240g) were added, followed by 0.6g hydroquinone and 0.5g benzyltriethylammonium chloride. Trichloroisocyanuric acid (99g,0.426mol, 90% of available chlorine content) is dissolved in acetone (360g) to prepare acetone solution of trichloroisocyanuric acid. Keeping the temperature of the reaction system at 2 ℃ under stirring, dripping acetone solution of trichloroisocyanuric acid from one feed inlet, dripping sodium bicarbonate solution with 5% of solute by mass from the other feed inlet, keeping the dripping simultaneously, controlling the pH of the reaction system between 6 and 6.5, finishing the dripping within about 2 hours, and then continuing the heat preservation reaction for 1 hour. The reaction was monitored by gas chromatography and the total amount of sodium bicarbonate solution used was 11 mL. Filtering, washing filter cake with 40mL of water and 40mL of acetone, discarding the filter cake, collecting the filtrate, combining the filtrates, and distilling under reduced pressure at a temperature lower than 40 ℃ to recover acetone and 2g of unreacted isoprene, which can be used for the next reaction. Cyclohexane (40mL multiplied by 3) is added into the distillation residual liquid for extraction, the extracted layered water layer is 264g which can be used for the next reaction, the organic layer is subjected to reduced pressure distillation at 40 ℃ to recover the solvent, and then a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol is obtained, the gas chromatography analysis shows that the total content of the product is 96 weight percent, and the yield is 96.7 percent.
The mixtures were separated in the manner of example 1 and then individually structurally characterized.
In the same manner as in example 1, 2.5% of by-product 2-chloromethyl-1, 3-butadiene was obtained in a yield.
The obtained product is a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 3
A2000 mL four-necked flask equipped with a thermometer and a stirring device was placed in an alcohol cooling bath, and isoprene (80g,1.176mol), acetone (300g) and water (240g) were added, followed by 0.13g hydroquinone and 0.26g benzyltriethylammonium chloride. Dichloroisocyanuric acid (116.2g,0.587mol, 67% available chlorine content) was dissolved in acetone (360g) to prepare an acetone solution of dichloroisocyanuric acid. Keeping the temperature of the reaction system at-5 ℃ under stirring, dripping acetone solution of dichloroisocyanuric acid from one feed inlet, dripping sodium bicarbonate solution with 5 percent of solute by mass from the other feed inlet, keeping dripping simultaneously, controlling the pH of the reaction system between 6 and 6.5, finishing dripping within about 2 hours, and continuing to keep the temperature for reaction for 1 hour. The reaction was monitored by gas chromatography and the total amount of sodium bicarbonate solution was 13 mL. Filtering, washing filter cake with 40mL of water and 40mL of acetone, discarding the filter cake, collecting the filtrate, combining the filtrates, and distilling under reduced pressure at a temperature lower than 40 ℃ to recover acetone and 2g of unreacted isoprene, which can be used for the next reaction. Cyclohexane (40mL multiplied by 3) is added into the distillation residual liquid for extraction, the extracted layered water layer is 267g, which can be used for the next reaction, the organic layer is subjected to reduced pressure distillation at 40 ℃ to recover the solvent, and a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol is obtained, and the gas chromatographic analysis shows that the total content of the product is 96 wt%, and the yield is 96.5%.
The mixtures were separated in the manner of example 1 and then individually structurally characterized.
In the same manner as in example 1, 2.7% of by-product 2-chloromethyl-1, 3-butadiene was obtained in a yield.
The obtained product is a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 4
A2000 mL four-necked flask equipped with a thermometer and a stirring device was placed in an alcohol cooling bath, and isoprene (80g,1.176mol), acetone (300g) and water (240g) were added, followed by 1.3g hydroquinone and 3.8g tetrabutylammonium bromide. Trichloroisocyanuric acid (95.7g,0.412mol, 90% of available chlorine content) is dissolved in acetone (360g) to prepare an acetone solution of trichloroisocyanuric acid. Keeping the temperature of the reaction system at 5 ℃ under stirring, dripping acetone solution of trichloroisocyanuric acid from one feed inlet, dripping sodium bicarbonate solution with solute mass fraction of 9% from the other feed inlet, keeping dripping simultaneously, controlling the pH of the reaction system between 6 and 6.5, finishing dripping within about 2 hours, and then continuing to keep the temperature for reaction for 1 hour. The reaction was monitored by gas chromatography for the total amount of sodium bicarbonate solution used of 6 mL. Filtering, discarding filter cake, collecting filtrate, combining, and distilling under reduced pressure at 40 deg.C below to recover acetone and 2.1g unreacted isoprene. And adding cyclohexane (40mL multiplied by 3) into the distillation residual liquid for extraction, wherein the extracted layered water layer is 261g and can be used for the next reaction, and the organic layer is subjected to reduced pressure distillation at 40 ℃ to recover the solvent to obtain a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol, wherein the total content of the product is 96.5 percent by weight and the yield is 96.8 percent as shown by gas chromatographic analysis.
The mixtures were separated in the manner of example 1 and then individually structurally characterized.
In the same manner as in example 1, 2.4% yield of by-product 2-chloromethyl-1, 3-butadiene was obtained.
The obtained product is a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 5
The procedure of example 1 was followed except that the pH of the reaction system was controlled to be in the range of 6.5 to 7.5, that is, the difference between the maximum value and the minimum value of the pH was 1.
Finally, a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and the total content of the product was 95% by weight as determined by gas chromatography, with a yield of 94%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 5.2% as a by-product.
The obtained product is a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 6
The procedure of example 1 was followed except that the pH of the reaction system was controlled to be 7 to 8, that is, the difference between the maximum and minimum values of pH was 1.
Finally, a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and the total content of the product was 94% by weight as determined by gas chromatography, with a yield of 94%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 5.7% as a by-product.
The nuclear magnetic hydrogen spectrum and gas chromatography analysis show that the obtained product is a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 7
The procedure of example 1 was followed except that a sodium hydrogencarbonate solution having a solute mass fraction of 5% was used and the pH of the reaction system was controlled to 5 to 6.
Finally, a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and gas chromatography analysis showed that the total content of the product was 93.5% by weight, and the yield was 94.5%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 4.6% as a by-product.
The product obtained was a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol by nuclear magnetic and gas chromatographic analysis, and 2-chloromethyl-1, 3-butadiene was the by-product.
Example 8
The procedure of example 1 was repeated, except that the temperature of the reaction system was controlled to 10 ℃.
A mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and gas phase analysis showed that the total content of the product was 93% by weight, and the yield was 93.5%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 6.2% as a by-product.
The obtained products are 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 9
The procedure of example 1 is followed except that the water in the isoprene containing system is the recovered aqueous phase of example 1 before the dropwise addition of the acetone solution of trichloroisocyanuric acid and the sodium bicarbonate solution.
A mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and gas phase analysis showed that the total content of the product was 92% by weight and the yield was 94%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 4.6% as a by-product.
The obtained products are 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 10
The procedure of example 1 was followed except that hydroquinone was not added as a polymerization inhibitor to the reaction system.
A mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and gas phase analysis showed that the total content of the product was 92% by weight and the yield was 93%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 6.3% as a by-product.
The obtained products are 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 11
The procedure of example 1 was followed except that benzyltriethylammonium chloride was not added as a phase transfer catalyst to the reaction system.
A mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and gas phase analysis showed that the total content of the product was 92% by weight and the yield was 93%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 6.8% as a by-product.
The obtained products are 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Example 12
The procedure of example 1 was followed except that the polymerization was carried out without adding a polymerization inhibitor and a phase transfer catalyst.
Finally, a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and gas chromatography analysis showed that the total content of the product was 93% by weight, and the yield was 88%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 11.3% as a by-product.
The obtained product is a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Comparative example 1
The method is carried out by adopting a method without adding a pH regulator.
A2000 mL four-necked flask equipped with a thermometer and a stirring device was placed in an alcohol cooling bath, and isoprene (80g,1.176mol), acetone (300g) and water (240g) were added, followed by 0.6g hydroquinone and 0.5g benzyltriethylammonium chloride. Trichloroisocyanuric acid (95.7g,0.412mol, 90% of available chlorine content) is dissolved in acetone (360g) to prepare an acetone solution of trichloroisocyanuric acid. The reaction system is kept at the temperature of 0 ℃ and stirred, the acetone solution of trichloroisocyanuric acid is dripped from the feed inlet, the dripping is finished within about 1.5 hours, and then the reaction is kept at the temperature for 1 hour. Filtering, washing filter cake with 40mL of water and 40mL of acetone, discarding filter cake, collecting filtrate, combining the filtrates, and distilling at a temperature lower than 40 ℃ under reduced pressure to recover acetone and 2.2g of unreacted isoprene. Cyclohexane (40mL multiplied by 3) is added into the distillation residual liquid for extraction, the extracted layered water layer is 261g, which can be used for the next reaction, the organic layer is decompressed and distilled at 40 ℃ to recover the solvent, and then the mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol is obtained, the gas chromatographic analysis shows that the total content of the product is 83 weight percent, and the yield is 87 percent.
The mixtures were separated in the manner of example 1 and then individually structurally characterized.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 11.2% as a by-product.
The obtained product is a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol through nuclear magnetic hydrogen spectrum and gas chromatography analysis, and the byproduct is 2-chloromethyl-1, 3-butadiene.
Comparative example 2
The procedure of example 1 was followed except that a 20% by mass sodium carbonate solution was used as the pH adjusting agent, and the pH of the reaction system was controlled to be 5 to 7, that is, the difference between the maximum and minimum values of pH was 2.
Finally, a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol was obtained, and the total content of the product was 80% by weight as determined by gas chromatography, with a yield of 69.7%.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 15.7% as a by-product.
The product obtained was a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol by nuclear magnetic and gas chromatographic analysis, and 2-chloromethyl-1, 3-butadiene was the by-product.
Comparative example 3
The method is carried out by adding a pH regulator and then adding N-chloroisocyanuric acid.
A2000 mL four-necked flask equipped with a thermometer and a stirring device was placed in an alcohol cooling bath, and isoprene (80g,1.176mol), acetone (300g) and water (240g) were added, followed by 0.6g of hydroquinone and 0.5g of benzyltriethylammonium chloride, and then 9mL of a sodium bicarbonate solution having a solute mass fraction of 6% was added. Trichloroisocyanuric acid (95.7g,0.412mol, 90% of available chlorine content) is dissolved in acetone (360g) to prepare an acetone solution of trichloroisocyanuric acid. Keeping the temperature of the reaction system at 0 ℃ under stirring, dripping acetone solution of trichloroisocyanuric acid from a feed inlet, keeping the pH of the reaction system between 3 and 7 in the dripping process, finishing dripping within about 1.5 hours, and keeping the temperature to react for 1 hour. Filtering, washing filter cake with 40mL of water and 40mL of acetone, discarding filter cake, collecting filtrate, combining, and distilling under reduced pressure at a temperature lower than 40 ℃ to recover acetone and 2.1g of unreacted isoprene. Adding cyclohexane (40mL multiplied by 3) into the distillation residual liquid for extraction, wherein the extracted layered water layer is 260g which can be used for the next reaction, and the organic layer is subjected to reduced pressure distillation at 40 ℃ to recover the solvent to obtain a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol, wherein the gas chromatographic analysis shows that the total content of the product is 80 wt%, and the yield is 72%.
The mixtures were separated in the manner of example 1 and then individually structurally characterized.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 23.2% as a by-product.
The product obtained was a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol by nuclear magnetic and gas chromatographic analysis, and 2-chloromethyl-1, 3-butadiene was the by-product.
Comparative example 4
The method is carried out by adopting a reverse dropwise adding mode, namely a method of dropwise adding isoprene into a system containing a pH regulator and N-chloroisocyanuric acid.
A2000 mL four-necked flask equipped with a thermometer and a stirring device was placed in an alcohol cooling bath, and 0.6g of hydroquinone and 0.5g of benzyltriethylammonium chloride were added, followed by trichloroisocyanuric acid (95.7g,0.412mol, 90% available chlorine content), 9mL of 6% sodium bicarbonate solution, and acetone (360 g). Isoprene (80g,1.176mol), acetone (300g), and water (240g) were mixed to prepare an isoprene-containing mixture. Cooling the reaction system containing trichloroisocyanuric acid to 0 ℃, dripping mixed liquid containing isoprene from a feed inlet while stirring, wherein the pH of the reaction system is between 3 and 6 in the dripping process, dripping is finished within about 1.5 hours, and the reaction is continued for 1.5 hours under heat preservation. Filtering, washing filter cake with 40mL of water and 40mL of acetone, discarding filter cake, collecting filtrate, combining filtrate, and distilling under reduced pressure at the temperature lower than 40 ℃ to recover acetone and 2.6g of unreacted isoprene. And adding cyclohexane (40mL multiplied by 3) into the distillation residual liquid for extraction, wherein an extracted layered water layer is 268g which can be used for the next reaction, and an organic layer is subjected to reduced pressure distillation at 40 ℃ to recover the solvent to obtain a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol, wherein the total content of the product is 87 weight percent and the yield is 81 percent as shown by gas chromatographic analysis.
The mixtures were separated in the manner of example 1 and then individually structurally characterized.
In the same manner as in example 1, 2-chloromethyl-1, 3-butadiene was obtained in a yield of 13% as a by-product.
The product obtained was a mixture of 1-chloro-2-methyl-3-buten-2-ol and 4-chloro-3-methyl-2-buten-1-ol by nuclear magnetic and gas chromatographic analysis, and 2-chloromethyl-1, 3-butadiene was the by-product.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (24)
1. A process for preparing a chlorohydrin comprising the steps of: in the presence of an organic solvent and water, adding N-chloroisocyanuric acid and/or a salt thereof and a pH regulator into isoprene for carrying out chlorohydrination reaction, wherein the adding speed is such that the difference between the maximum value and the minimum value of the pH of a reaction system is not higher than 1.
2. The method according to claim 1, wherein the addition rate is such that the difference between the maximum value and the minimum value of the pH of the reaction system is not higher than 0.5.
3. The method according to claim 1, wherein the volume ratio of the organic solvent to the water is 1 (0.1-5);
and/or the total amount of the organic solvent and the water is 1-20mL relative to each gram of isoprene.
4. The method according to claim 1, wherein the volume ratio of the organic solvent to the water is 1 (0.1-2);
and/or the total amount of the organic solvent and the water is 4-15mL relative to each gram of isoprene.
5. The method according to any one of claims 1 to 4, wherein the organic solvent is selected from at least one of acetone, methanol and methyl isobutyl ketone.
6. The method of claim 5, wherein the organic solvent is acetone.
7. The method of any one of claims 1-4, wherein the N-chloroisocyanuric acid is selected from trichloroisocyanuric acid or dichloroisocyanuric acid;
and/or, the salt of N-chloroisocyanuric acid is selected from at least one of sodium dichloroisocyanurate, potassium dichloroisocyanurate, calcium dichloroisocyanurate and magnesium dichloroisocyanurate.
8. The method according to any one of claims 1 to 4, wherein the pH adjusting agent is at least one selected from the group consisting of an aqueous solution of sodium bicarbonate, an aqueous solution of potassium bicarbonate, an aqueous solution of sodium carbonate, an aqueous solution of sodium acetate, and an aqueous solution of potassium carbonate;
and/or the mass fraction of the solute of the pH regulator is 1-15 wt%.
9. The method of any one of claims 1-4, wherein the pH adjusting agent is an aqueous solution of sodium bicarbonate;
and/or the mass fraction of the solute of the pH regulator is 1-9 wt%.
10. The process according to any one of claims 1 to 4, wherein the molar ratio of N-chloroisocyanuric acid and/or salts thereof to isoprene is (0.1-1): 1.
11. the process according to any one of claims 1 to 4, wherein the molar ratio of N-chloroisocyanuric acid and/or salts thereof to isoprene is (0.33-0.5): 1.
12. the method according to any one of claims 1 to 4, wherein the chlorohydrination reaction system has a pH of 5 to 8.
13. The method according to any one of claims 1 to 4, wherein the chlorohydrination reaction system has a pH of 6 to 6.5.
14. The method according to any one of claims 1-4, wherein the method comprises: adding the solution of N-chloroisocyanuric acid and/or salt thereof and a pH regulator into a mixed solution containing isoprene, an organic solvent and water for reaction, wherein the adding speed of the solution of N-chloroisocyanuric acid and/or salt thereof and the pH regulator ensures that the pH of the reaction system is maintained within the range of 5-8 and the difference value between the maximum value and the minimum value is not higher than 1, and then continuing the reaction for 0.5-2 h.
15. The process according to claim 14, wherein the solution of N-chloroisocyanuric acid and/or a salt thereof and the pH adjustor are added at such a rate that the pH of the reaction system is maintained in the range of 5 to 8 and the difference between the maximum value and the minimum value is not higher than 0.5.
16. The process according to any one of claims 1 to 4, wherein the temperature of the chlorohydrination reaction is from-10 ℃ to 30 ℃; the time of the chlorohydrination reaction is 1-5 h.
17. The process according to any one of claims 1-4, wherein the temperature of the chlorohydrination reaction is from-5 ℃ to 5 ℃; the time of the chlorohydrination reaction is 1-3 h.
18. The process according to any one of claims 1 to 4, wherein the chlorohydrination reaction is carried out in the presence of a polymerization inhibitor and/or a phase transfer catalyst.
19. The method of claim 18, wherein the polymerization inhibitor is selected from at least one of hydroquinone, 2, 6-di-t-butyl-p-toluidine ether, p-hydroxyanisole, and p-benzoquinone.
20. The method of claim 18, wherein the polymerization inhibitor is hydroquinone.
21. The process of claim 18, wherein the phase transfer catalyst is selected from at least one of tetrabutylammonium bromide, tetrabutylammonium chloride, and benzyltriethylammonium chloride.
22. The process of claim 18, wherein the phase transfer catalyst is benzyltriethylammonium chloride.
23. The method according to claim 18, wherein the polymerization inhibitor is used in an amount of 0.05 to 5 moles per 100 moles of isoprene;
and/or the phase transfer catalyst is used in an amount of 0.05 to 2 moles per 100 moles of isoprene.
24. The method according to claim 18, wherein the polymerization inhibitor is used in an amount of 0.1 to 1 mole per 100 moles of isoprene;
and/or the phase transfer catalyst is used in an amount of 0.1 to 1 mole per 100 moles of isoprene.
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