Process, plant and reactor for producing 3-methylsulfolene

Abstract

The invention is directed toward the production of 3-methylsulfolene using isoprene and can be used in the chemical and petrochemical industry. A process of producing 3-methylsulfolene using isoprene comprises reacting isoprene with sulfur dioxide in a cyclization reaction in the presence of an isoprene polymerization inhibitor and a tenfold excess of solvent relative to the amount of 3-methylsulfolene produced, at a temperature of 60-80°C and a pressure of 1.0 MPa for 1-2 hours, and subsequently purifying and drying the 3-methylsulfolene. The process is carried out in a plant for producing 3-methylsulfolene which consists of a batch reaction apparatus having an agitator and a heat exchange jacket, a fractionating column, pumps, feedstock tanks, final product tanks, intermediate tanks, a sulfur oxidation unit, a filter unit, and a unit of heat exchangers that are interconnected by a system of pipes with shutoff valves. The process of producing 3-methylsulfolene provides a high yield of high-purity target product, prevents large losses of solvent and enables more efficient use of sulfur, and can be used for industrial-scale production with the aid of the proposed plant, which provides for efficient production of 3-methylsulfolene.

Description

[0001] METHOD, APPARATUS AND REACTOR FOR PRODUCING

[0002] 3 -METHI LSULFO LENA

[0003] AREA OF TECHNOLOGY

[0004] The method, installation and reactor for producing 3-methylsulfolene are intended for the production of 3-methylsulfolene on an industrial scale and can be used in the chemical industry.

[0005] 3-Methylsulfolene is used as a universal solvent, as well as in the production of cis-3,4-dihydroxysulfolanes, bromo derivatives of sulfolane, and other sulfur-containing substances, in the production of polysulfone semipermeable membranes, and as an inhibitor of diolefin polymerization. An important application of 3-methylsulfolene is the possibility of obtaining ultra-pure isoprene for synthetic purposes. In the first stage, 3-methylsulfolene is obtained, then purified and then decomposed upon heating to yield isoprene. However, the most promising application of 3-methylsulfolene is for the synthesis of 3-methylsulfolane, which is used as a solvent in extraction and extractive rectification processes for the separation of benzene, toluene, and xylenes from hydrocarbon mixtures, solvents of quaternary ammonium bases, nitrocellulose, and some polymer compounds, and is also an intermediate product in the production of pest control agents.

[0006] Information on the methods for producing 3-methylsulfolene is extremely insufficient; data on the chemistry of the process are provided in outdated literary sources (Rozantsev E.G. Sulfolanes and Some Aspects of Their Industrial Application. Chemical Industry, 1961, No. 7, p. 12); only recently have several patents been published in the open press, protecting long-standing works on similar topics.

[0007] PRIOR ART

[0008] A method is known for producing cyclic 1,3-butadiene sulfone (3-sulfolene) by heating liquid 1,3-butadiene under pressure with sulfur dioxide in the presence of linear polysulfone formation inhibitors, characterized in that the 1,3-butadiene is a fraction of C4 hydrocarbons from industrial gasoline pyrolysis gas separation plants (patent RU 2065857, IPC C07D 333 / 48, filed 03 / 27 / 1995, published 08 / 27 / 1996).

[0009] The closest to the claimed invention is a method for producing monomethyl homologues of the cyclic sulfone butadiene-1,3 (sulfolene-3) by heating under pressure a liquid mixture containing isoprene and pentadiene-1,3 with liquid sulfur dioxide in the presence of catalysts dissolved in this mixture, characterized in that, in order to increase the efficiency of the process, a fraction of hydrocarbons-Cs from industrial installations for separating gasoline pyrolysis gases is used as a source of isoprene and pentadiene-1,3 (patent RU 2065858, IPC C07D 333 / 48, declared on 13.06.1995, published on 27.08.1996).

[0010] What both patents have in common is the use of the Diels-Alder reaction to produce sulfolene and its homologues. However, a common drawback is the lack of technological and instrumental development of the process.

[0011] DISCLOSURE OF THE INVENTION

[0012] The objective of the development of this invention is to develop a technological method, installation and reactor that make it possible to implement the synthesis of 3-methyl sulfolene with high conversion and minimization of process flows with a reduction in the technogenic impact on the environment.

[0013] The problem is solved due to the fact that the method for producing 3-methylsulfolene based on isoprene includes the following stages: a) oxidizing sulfur in a medium of concentrated oxygen to obtain sulfur dioxide; b) condensing sulfur dioxide at a temperature of no higher than minus 10 °C and atmospheric pressure, followed by accumulation in a vessel with a cooling jacket, into which a coolant is fed; c) mixing liquid sulfur dioxide from stage (b) with the first part of the solvent at a temperature of no higher than minus 10 °C and atmospheric pressure in a batch reaction apparatus with a stirrer; d) mixing a solution of sulfur dioxide in the solvent medium from stage (c) with an isoprene polymerization inhibitor and isoprene under atmospheric pressure and at a temperature of no higher than minus 10 °C in excess against the stoichiometric ratio with isoprene according to the Diels-Alder reaction in a batch reaction apparatus with a stirrer and a heat exchange jacket;d) the reaction medium prepared in step d) is heated with a heat carrier through the heat exchange jacket of the batch reaction apparatus to 40 °C, corresponding to the start of the reaction, and then the chemical reaction is carried out with stirring with an increase in temperature to 60-80 °C and a pressure of up to 1.0 MPa for 1-2 hours to obtain the first solution of 3-methylsulfolene; e) the first solution of 3-methylsulfolene of step (e) is heated with a heat carrier to 90-100 °C and the residual sulfur dioxide and excess solvent are evaporated, directed to step k), obtaining the second solution of 3-methylsulfolene; g) the second solution of 3-methylsulfolene of step (e) is mixed with the second part of the solvent, obtaining a third solution of 3-methylsulfolene; c) the third solution of 3-methylsulfolene is cooled with stirring to 20 °C, whereby 3-methylsulfolene crystallizes, creating, with stirring, a suspension with a dispersed phase of 3-methylsulfolene in the solvent medium;i) filtering the suspension from step h) to obtain a dried precipitate of 3-methylsulfolene and a solvent-filtrate vapor, which is sent to step g) as the second part of the solvent; k) further drying the dried precipitate of 3-methylsulfolene from step i) to obtain a marketable product and exhaust solvent vapors; k) cooling the vapors of residual sulfur dioxide and excess solvent from step e) and subjecting them to rectification to obtain sulfur dioxide vapors sent to step b) and a liquid solvent sent to step c) as the first part of the solvent; in this case, the amount of the second part of the solvent in stage g) must be at least tenfold excess in relation to the amount of 3-methylsulfolene produced, the residual sulfur dioxide vapor and excess solvent in stage l) are cooled before rectification to a temperature not exceeding 80 °C at a pressure of 0.11-0.12 MPa;the filtration of the suspension in stage h) is carried out in a vacuum at a residual pressure of at least 40 mm Hg, the solvent-filtrate vapors leaving stage h) are subjected to thermal neutralization on a candle, and stages c)-h) are carried out in a single batch reaction apparatus with a stirrer and a heat exchange jacket in accordance with the cyclogram of stages c)-h), while the second part of the solvent in stage g) is fed into the reaction apparatus in an ascending flow at a speed lower than the hovering speed of the 3-methylsulfolene crystals.

[0014] The efficiency of the proposed method for producing 3-methylsulfolene is based on the fact that the method is implemented as a single-phase process at moderate temperatures and pressures according to a fairly simple reaction (Figure 1) from common and accessible starting materials - isoprene and sulfur oxide.

[0015] The proposed solutions are related to the specifics of the industrial implementation of the process for producing 3-methylsulfolene. 1. The requirement that the amount of the second portion of the solvent in step g) must be at least tenfold excess over the amount of 3-methylsulfolene produced is related to the reactor operation during step e), when residual sulfur dioxide and excess solvent are evaporated and sent to step k), producing a second solution of 3-methylsulfolene. The resulting second solution of 3-methylsulfolene, under the reactor operating conditions from steps e) to h), changes temperature from 100 °C to 20 °C and changes its phase state. At high temperatures, the reaction medium is liquid 3-methylsulfolene with significant dilution by the previously evaporating first portion of the solvent.As the temperature decreases, 3-methylsulfolene crystallizes in the remaining first portion of the solvent, forming a concentrated suspension with a solids concentration of 30-60%. This pasty mass is difficult to remove from the reactor for subsequent process steps. Repeated dilution of the suspension with the second portion of the solvent produces a suspension with a solids concentration of 3-6%, easily removed from the reactor by pump or gravity.

[0016] 2. For efficient operation of the distillation column, the residual sulfur dioxide vapor and excess solvent in step (k) must be cooled before distillation to a temperature no higher than 80°C at a pressure of 0.11-0.12 MPa. This creates a vapor-liquid mixture at the column inlet, ensuring the removal of solvent of any specified purity. When the feedstock is introduced into the column in the vapor phase, the solvent purity is limited by the phase equilibrium of the components being separated. The cooling temperature is limited to 80°C because the entire stream entering the column will then be in the vapor phase.

[0017] 3. The need to filter the suspension in step 3) under vacuum at a residual pressure of at least 40 mmHg is determined by the fact that increasing pressure intensifies solvent evaporation. Solvent evaporation leads to irreversible losses, worsening the environmental situation (air pollution), or necessitates the installation of additional exhaust gas purification systems with solvent return to the process, which degrades the economic performance of the process.

[0018] 4. To reduce emissions of toxic substances into the atmosphere, the solvent-filtrate vapors leaving stage 3) are subjected to thermal neutralization in a candle.

[0019] 5. The main stages of the synthesis of 3-methylsulfolene c)-h) are carried out in a single batch reaction apparatus with a stirrer and a heat exchange jacket in accordance with the cyclogram of stages c)-h), which makes it possible to reduce the number of apparatuses in the installation and ensure automated switching from one stage to another.

[0020] 6. During intense crystallization of 3-methylsulfolene, mechanical stirring of the thick suspension becomes energy-consuming; stirring the diluted suspension with the second portion of the solvent is more efficient. In this case, the solvent in step g) should be fed into the reaction apparatus in an ascending flow at a velocity lower than the velocity of the 3-methylsulfolene crystals, as this will cause the suspension to fluidize.

[0021] In cases where the productivity of the 3-methylsulfolene production plant is low, it is advisable to feed sulfur dioxide into the process from cylinders, which allows for the reduction of stages a) and b), thereby reducing the capital costs of implementing the process.

[0022] It is advisable to feed isoprene into the reaction apparatus in portions at a temperature of 25-30 °C (the temperature of isoprene in the storage tank) under nitrogen pressure to avoid a sharp rise in temperature in the reaction apparatus and the release of sulfur dioxide vapors outside the reaction apparatus.

[0023] It is advisable to use isopropyl alcohol as a solvent in the process, as it is readily available, inexpensive, and dissolves both the feedstock components and the reaction product equally well. Hydroquinone, which exhibits high inhibitory activity, is recommended as an isoprene polymerization inhibitor.

[0024] It is efficient to use a single component as a coolant and heat transfer fluid circulating in the jacket of the reaction apparatus of the reaction block, providing an operating temperature range from minus 20 to plus 120 °C, which will reduce the number of flows in the process and simplify maintenance.

[0025] It is recommended to use n-octane, or n-nonane, or octane-nonane fraction as such a refrigerant and heat transfer agent, since these hydrocarbons, in terms of solid-liquid-vapor phase transformation temperatures, satisfy the thermal characteristics of the process, and the use of a fraction that is cheaper than pure components will increase the efficiency of the process.

[0026] The method for producing 3-methylsulfolene is implemented in a plant that requires a minimum of equipment; the equipment may consist of a batch reaction apparatus with a stirrer and a heat exchange jacket, a distillation column, pumps, raw material, product and intermediate tanks, a sulfur oxidation unit, a filtration unit and a block of heat exchange apparatuses connected by a pipeline system with shut-off valves.

[0027] It is advisable to use a heat exchange jacket in a batch reactor with a stirrer and a heat exchange jacket, which facilitates the process for producing 3-methylsulfolene, equipped with coolant inlet and outlet fittings and coolant inlet and outlet fittings, an inlet fitting for the second solvent portion at the bottom of the reactor, and an outlet fitting for the second solvent portion at the top of the reactor, above the reaction medium level in step (g). This allows for the introduction of coolant or refrigerant into the heat exchange jacket and the circulation of the second solvent portion without overcomplicating the reactor design. It is advisable to form a coolant generation circuit using propane cooling and a coolant generation circuit using water vapor condensation in the heat exchange apparatus block, ensuring cyclic reactor operation.

[0028] It is also advisable to use a drum vacuum filter and a vacuum pump in the filtration unit, providing a residual pressure of up to 40 mm Hg, creating optimal filtration conditions both in terms of pressure and the formation of a sediment layer on the filter surface.

[0029] It is recommended to use a closed sulfur combustion chamber in the sulfur oxidation unit, as this design is the most environmentally friendly. LIST OF DRAWINGS

[0030] The reaction mechanism for producing 3-methyl sulfolene from isoprene using the method of the present invention is shown in Figure 1.

[0031] Figure 2 shows a schematic diagram of one of the possible implementation options for the method of obtaining 3-methylsulfolene using the following designations:

[0032] 1-34 - streams,

[0033] 100 - sulfur oxidation unit,

[0034] 200 - block for preparation of initial reagents,

[0035] 300 - reaction block,

[0036] 400 - solvent regeneration unit,

[0037] 500 - filtration unit,

[0038] 501 - first stage of drying,

[0039] 502 - the second stage of drying,

[0040] 600 - 3-methylsulfolene storage unit.

[0041] The proposed method for producing 3-methylsulfolene is implemented in a batch reactor with a stirrer and a heat-exchange jacket. Figure 3 shows the reactor design using the following designations: 41 - housing,

[0042] 42 - feedstock inlet nozzle,

[0043] 43 - reaction product outlet nipple,

[0044] 44 - mixing device drive shaft,

[0045] 45 - pocket for collecting recirculated waste,

[0046] 46 - paddle mixers,

[0047] 47 - anchor stirrer,

[0048] 48 - recirculated exhaust outlet fitting,

[0049] 49 - recirculated air inlet fitting,

[0050] 50 - heat exchange jacket,

[0051] 51 - refrigerant inlet nipple,

[0052] 52 - refrigerant outlet fitting,

[0053] 53 - coolant inlet nipple,

[0054] 54 - coolant outlet nipple.

[0055] BRIEF DESCRIPTION OF DRAWINGS

[0056] In one embodiment of the method for producing 3-methylsulfone, at step (a) sulfur is fed to the sulfur oxidation unit 100 via stream 1 and concentrated oxygen via stream 2 into the reaction apparatus. A closed sulfur combustion chamber can be used to convert sulfur to sulfur dioxide. Combustion of sulfur in a concentrated oxygen environment produces sulfur dioxide, which is then fed via stream 3 to step (b) in the feedstock preparation unit 200 into a feedstock tank with a stirrer and cooling jacket, where it is maintained in liquid form at a temperature of up to minus 10°C by circulating the coolant via streams 4 and 5 in the heat exchange jacket. Fresh isoprene enters the feedstock preparation unit 200 in a raw material tank with a stirrer and a cooling jacket, where it is maintained in liquid form under atmospheric pressure at a temperature not exceeding minus 10 °C by feeding coolant into the heat exchange jacket in flows 10 and 11.Liquid sulfur dioxide enters stage (c) of reaction block 300 via stream 6 in a batch-type apparatus with a stirrer, where it is mixed with the first portion of the solvent, entering via stream 12 from the corresponding feed tank of the initial reagent preparation unit 200, with an isoprene polymerization inhibitor supplied via stream 7, and cooled isoprene supplied via stream 9 under atmospheric nitrogen pressure and at a temperature no higher than minus 10°C in excess of the stoichiometric ratio for the Diels-Alder reaction. Isopropyl alcohol can be used as the solvent, and hydroquinone can be used as the isoprene polymerization inhibitor.The reaction mass is prepared by stirring at stage (d), after which, at stage (d), the reaction mass is heated with a heat carrier circulating through the heat exchange jacket of the batch reaction apparatus to 40 °C, corresponding to the start of the reaction, and then the chemical reaction is carried out with stirring, increasing the temperature to 60-80 °C and the pressure to 1.0 MPa for 1-2 hours to obtain the first solution of 3-methylsulfolene. At stage (e), the first solution of 3-methylsulfolene is heated with a heat carrier to 90-100 °C by streams 13 and 14 circulating through the heat exchange jacket of the batch reaction apparatus, and the residual sulfur dioxide and excess solvent are evaporated by means of the heat carrier, directed by stream 19 to stage l) in the solvent regeneration unit 400, where they are subsequently separated, thereby obtaining a second solution of 3-methylsulfolene, which is a sulfolene concentrate with a 3-methylsulfolene content of about 95-99%.At stage (g), carried out in a batch reaction apparatus, the second solution of 3-methylsulfolene of stage (e) is mixed with a second portion of the solvent fed into the lower part of the reaction apparatus in an ascending flow at a speed lower than the speed of the 3-methylsulfolene crystals by flow 20, thereby obtaining a third solution of 3-methylsulfolene, which at stage (z) is cooled to 20 °C with intensive mixing by feeding a coolant into the heat exchange jacket of the reaction apparatus by flows 21 and 22, whereby 3-methylsulfolene crystallizes, creating during mixing a suspension with a dispersed phase of 3-methylsulfolene in a solvent medium, which is directed by flow 25 into the filtration unit 500.The reactor in the reaction block 300 is a batch reaction apparatus with a stirrer and a heat exchange jacket, which is equipped with coolant inlet and outlet fittings and coolant inlet and outlet fittings, an inlet fitting for the second part of the solvent at the bottom of the apparatus and an outlet fitting for the second part of the solvent in the upper part of the apparatus above the level of the reaction medium.

[0057] The filtration of the suspension in step (h) is carried out in a vacuum at a residual pressure of at least 40 mm Hg. The amount of the second portion of the solvent in step (g) must be at least tenfold excess in relation to the amount of 3-methylsulfolene produced. In the filtration unit 500, step (i) is carried out, in which the suspension with the dispersed phase of 3-methylsulfolene in the solvent medium is filtered in the first drying stage 501 to obtain a dried precipitate of 3-methylsulfolene fed by stream 26 to the second stage, and the solvent-filtrate vapors, which are subjected to thermal neutralization on a candle by stream 27, are sent to step (g) as the second portion of the solvent and mixed with stream 20 of the second portion of the solvent leaving the solvent regeneration unit 400.Then, the dried precipitate of 3-methylsulfolene, received by stream 26, is further dried at step (k) at the second drying stage 502 in the filtration unit 500 to obtain crystalline 3-methylsulfolene, which is discharged by stream 28 into the 3-methylsulfolene storage unit, from where it is sent to the consumer as a commercial product by stream 30; the solvent vapors formed at the second drying stage 502 are sent by stream 29 for purification to the solvent regeneration unit 400. In the filtration unit 500, a drum vacuum filter is used at the first drying stage 501, and a vacuum pump is used at the second drying stage 502, providing a residual pressure of up to 40 mm Hg.The residual sulfur dioxide vapor and excess solvent from step (e), fed by stream 19 to solvent regeneration unit 400, are cooled and subjected to rectification to obtain sulfur dioxide vapor directed by stream 32 to step (b) into the raw material tank with a cooling jacket of the initial reagent preparation unit 200, the thermal regime in which is maintained due to the circulation of the coolant by streams 33 and 34 through the heat exchange jacket, and liquid solvent directed by stream 31 into the raw material tank with a cooling jacket of the initial reagent preparation unit 200 for feeding to step (c) as the first portion of the solvent. In this case, the residual sulfur dioxide vapor and excess solvent in step (l) are cooled before rectification to a temperature of no higher than 80 °C at a pressure of 0.11-0.12 MPa (the rectification column is not shown in the diagram).The stages of the method (c)-(h) are carried out in a single batch reaction apparatus with a stirrer and a heat-exchange jacket in accordance with the cyclogram of stages (c)-(h). A block of heat-exchange apparatuses connected by a system of pipelines with shut-off valves is provided in the reaction block 300. A circuit for creating a coolant supplied to the heat-exchange jacket by streams 21 and 22 in stage (h) is formed in the block of heat-exchange apparatuses, using cooling due to the circulation of propane by streams 23 and 24, and a circuit for creating a heat-transfer agent supplied to the heat-exchange jacket by streams 13 and 14 in stages (d)-(g) using the condensation of water vapor.Thus, the water leaving the heat exchange jacket is heated by flow 14 due to steam flow 15, moving in a straight line through the tube space of the heat exchanger and leaving the tube space in the form of condensate by flow 16, while the heated water by flow 13 again enters the heat exchange jacket, and the condensate by flow 16 enters the tube space of the second heat exchanger, where it is heated by steam circulating in the intertube space by flows 17 and 18.

[0058] The batch reaction apparatus consists of a housing 41 having a cylindrical part and two elliptical bottoms, inside which a drive shaft of the mixing device 44 is placed, at the end of which an anchor stirrer 47 is fixed, along the height of the drive shaft of the mixing device 44 at an equal distance from each other, paddle stirrers 46 are fixed, the upper part of the reaction apparatus above the outer paddle stirrer 6 is equipped with a pocket for collecting recirculated 45, the upper bottom is equipped with a nozzle for inlet of the initial products 42, the lower bottom is equipped with a nozzle for outlet of the reaction product 43 and a nozzle for inlet of recirculated 49, above the lower boundary of the pocket for collecting recirculated 45 in the cylindrical part of the housing 41 a nozzle for outlet of recirculated 48 is located. The housing 41 of the reaction apparatus is dressed in a heat exchange jacket 50, equipped with a nozzle for inlet of coolant 51, a nozzle coolant outlet 52, coolant inlet fitting 53 and coolant outlet fitting 54.

[0059] Thus, the claimed invention addresses the problem of developing a method for producing 3-methylsulfolene via the cyclization reaction of isoprene with sulfur dioxide, ensuring a high yield and high purity of the target product. The proposed method will avoid significant solvent losses due to repeated use after the solvent regeneration unit, improve sulfur utilization, and is applicable for industrial production, for which a plant and reactor have been developed that ensure the efficient production of 3-methylsulfolene. The technical result consists in developing a process method, plant, and reactor that enable the production of 3-methylsulfolene with high conversion and minimized process flows, while reducing capital costs, environmental impact, and solvent loss.

Claims

CLAUSES OF THE INVENTION 1. A method for producing 3-methylsulfolene based on isoprene, comprising the following stages: a) oxidizing sulfur in a concentrated oxygen medium to produce sulfur dioxide; b) condensing sulfur dioxide at a temperature of no higher than minus 10 °C and atmospheric pressure, followed by accumulation in a vessel with a cooling jacket, into which a coolant is fed; c) mixing liquid sulfur dioxide from step (b) with a first portion of the solvent at a temperature of no higher than minus 10 °C and atmospheric pressure in a batch reactor with a stirrer; d) mixing a solution of sulfur dioxide in the solvent medium from step (c) with an isoprene polymerization inhibitor and isoprene under atmospheric pressure and at a temperature of no higher than minus 10 °C in excess against the stoichiometric ratio with isoprene according to the Diels-Alder reaction in a batch reactor with a stirrer and a heat exchange jacket;d) the reaction medium prepared in step d) is heated with a heat carrier through the heat exchange jacket of the batch reaction apparatus to 40 °C, corresponding to the start of the reaction, and then the chemical reaction is carried out with stirring with an increase in temperature to 60-80 °C and a pressure of up to 1.0 MPa for 1-2 hours to obtain the first solution of 3-methylsulfolene; e) the first solution of 3-methylsulfolene of step (e) is heated with a heat carrier to 90-100 °C and the residual sulfur dioxide and excess solvent are evaporated, directed to step k), obtaining the second solution of 3-methylsulfolene; g) the second solution of 3-methylsulfolene of step (e) is mixed with the second part of the solvent, obtaining a third solution of 3-methylsulfolene; h) the third solution of 3-methylsulfolene is cooled with stirring to 20 °C, whereby 3-methylsulfolene crystallizes, creating upon stirring a suspension with a dispersed phase of 3-methylsulfolene in a solvent medium; i) the suspension from step h) is filtered to obtain a dried precipitate of 3-methylsulfolene and a solvent-filtrate vapor, which is sent to step g) as the second part of the solvent; j) the dried precipitate of 3-methylsulfolene from step i) is further dried to obtain a commercial product and exhaust solvent vapors; k) the vapors of residual sulfur dioxide and excess solvent from step e) are cooled and subjected to rectification to obtain sulfur dioxide vapors sent to step b), and a liquid solvent sent to step c) as the first part of the solvent;characterized in that the amount of the second portion of the solvent in step g) is provided in at least a tenfold excess in relation to the amount of 3-methylsulfolene produced, the vapors of residual sulfur dioxide and excess solvent in step l) are cooled before rectification to a temperature of no more than 80 °C at a pressure of 0.11-0.12 MPa; the filtration of the suspension in step h) is carried out in a vacuum at a residual pressure of no less than 40 mm Hg, the vapors of the solvent-filtrate leaving step h) are subjected to thermal neutralization on a candle, and steps c)-h) are carried out in a single batch reaction apparatus with a stirrer and a heat exchange jacket in accordance with the cyclogram of steps c)-h), wherein the second portion of the solvent in step g) is fed into the reaction apparatus in an ascending stream at a speed lower than the hovering speed of the 3-methylsulfolene crystals.

2. The method according to paragraph 1, characterized in that sulfur dioxide is supplied from cylinders.

3. The method according to paragraph 1, characterized in that isoprene is fed into the reaction apparatus in portions at a temperature of 25-30 °C under nitrogen pressure.

4. The method according to paragraph 1, characterized in that isopropyl alcohol is used as a solvent.

5. The method according to claim 1, characterized in that hydroquinone is used as an isoprene polymerization inhibitor.

6. The method according to paragraph 1, characterized in that a single component is used as a coolant and a heat carrier circulating in the jacket of the reaction apparatus of the reaction block, providing an operating temperature range from minus 20 to plus 120 °C.

7. The method according to paragraph 1, characterized in that n-octane, or n-nonane, or an octane-nonane fraction is used as the coolant and heat transfer agent.

8. An installation for producing 3-methylsulfolene according to paragraph 1, consisting of a batch reaction apparatus with a stirrer and a heat exchange jacket, a distillation column, pumps, raw material, product and intermediate tanks, a sulfur oxidation unit, a filtration unit and a block of heat exchange apparatuses connected by a pipeline system with shut-off valves.

9. The installation according to paragraph 8, characterized in that in the block of heat exchange apparatuses a circuit for creating a coolant using propane cooling and a circuit for creating a heat carrier using the condensation of water vapor are formed.

10. The installation according to paragraph 8, characterized in that a drum vacuum filter and a vacuum pump are used in the filtration unit, providing a residual pressure of up to 40 mm Hg. And. The installation according to paragraph 8, characterized in that a closed sulfur combustion chamber is used in the sulfur oxidation unit.

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