A method and device for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt

Abstract

The invention discloses a synthetic method and device of phenylene-bis-benzimidazole-tetrasulfonic acid disodium salt, and relates to the technical field of chemical synthesis, and the synthetic method of the phenylene-bis-benzimidazole-tetrasulfonic acid disodium salt comprises the following steps: terephthalaldehyde, catalyst, solvent and o-phenylenediamine are mixed, and a ring-closure reaction is carried out to obtain phenylene-bis-benzimidazole; the phenylene-bis-benzimidazole is mixed with a sulfonating agent, and a sulfonation reaction is carried out to obtain a sulfonic acid derivative of phenylene-bis-benzimidazole; the sulfonic acid derivative of the phenylene-bis-benzimidazole is mixed with a sodium salt solution, and crystals are separated to obtain phenylene-bis-benzimidazole-tetrasulfonic acid disodium salt. The synthetic method of the present invention solves the phenomenon of high-temperature sublimation of o-phenylenediamine in the ring-closure reaction, avoids causing the loss of o-phenylenediamine raw materials, improves the utilization rate of o-phenylenediamine, and then improves the yield of the product.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a method and a device for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt. Background Art

[0002] Disodium phenyl dibenzimidazole tetrasulfonate, English name is DISODIUM PHENYL DIBENZIMIDAZOLETETRASULFONATE (DPDT), alias: sodium salt of phenylene dibenzimidazole sulfonate. DPDT is a water-soluble UVA protective agent with an absorption wavelength between 290-370nm and good light stability.

[0003] The main function of disodium phenyl dibenzimidazole tetrasulfonate in cosmetics and skin care products is a chemical sunscreen. It is non-comedogenic, has a low risk factor, is relatively safe, and can be used with confidence.

[0004] However, the current industrial preparation method of disodium phenyl dibenzimidazole tetrasulfonate has the following disadvantages: the chemical synthesis process has a high reaction temperature and is prone to produce a large amount of white smoke, which is relatively dangerous. Summary of the invention

[0005] The main purpose of the present invention is to provide a method and device for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, aiming to solve the problem of too high reaction temperature and easy generation of a large amount of white smoke in the prior art.

[0006] To achieve the above object, the present invention provides a method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, comprising the following steps:

[0007] S10, mixing terephthalaldehyde, a catalyst, a solvent and o-phenylenediamine, and performing a cyclization reaction to obtain phenylene-bisbenzimidazole;

[0008] S20, mixing the phenylene-bisbenzimidazole with a sulfonating agent, and performing a sulfonation reaction to obtain a sulfonic acid derivative of the phenylene-bisbenzimidazole;

[0009] S30, mixing the sulfonic acid derivative of phenylene-bisbenzimidazole with a sodium salt solution to precipitate crystals to obtain phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt.

[0010] In one embodiment, in step S10:

[0011] The molar ratio of the terephthalaldehyde to the catalyst is 1:(0.5-2.0); and / or,

[0012] The molar ratio of the terephthalaldehyde to the o-phenylenediamine is 1:(2.0-2.5); and / or,

[0013] The mass ratio of the terephthalaldehyde to the solvent is 1:(8-30); and / or,

[0014] The catalyst includes sodium metabisulfite, sodium sulfite or sulfur dioxide.

[0015] In one embodiment, step S10 includes:

[0016] Terephthalaldehyde, a catalyst and o-phenylenediamine are sequentially added into a solvent to carry out a cyclization reaction to obtain phenylene-bisbenzimidazole; wherein the solvent comprises water or an aqueous solution of alcohol; and the volume ratio of alcohol to water in the aqueous solution of alcohol is 1:(1-3).

[0017] In one embodiment, step S10 includes:

[0018] S11, mixing terephthalaldehyde, a catalyst and a first solvent to obtain a first solution;

[0019] S12, mixing o-phenylenediamine and a second solvent to obtain a second solution;

[0020] S13, mixing the first solution and the second solution, and performing a cyclization reaction to obtain phenylene-bisbenzimidazole;

[0021] The boiling point of the first solvent and / or the second solvent is less than or equal to 100°C.

[0022] In one embodiment, in step S11, the mass ratio of the terephthalaldehyde to the first solvent is 1:(6-20); and / or,

[0023] In step S12, the mass ratio of the o-phenylenediamine to the second solvent is 1:(2-10); and / or,

[0024] In step S11, the first solvent includes water or an aqueous solution of alcohol; the alcohol in the aqueous solution of alcohol includes at least one of methanol and ethanol; and / or,

[0025] In step S12, the second solvent includes alcohol or an alcohol aqueous solution; the alcohol in the alcohol and the alcohol aqueous solution includes at least one of methanol and ethanol; and / or,

[0026] Step S13 comprises: mixing the first solution and the second solution by dropwise addition, the mixing time is 30 to 300 minutes, the mixing temperature is 60 to 90° C., and after the mixing is completed, performing a cyclization reaction at 80 to 120° C. for 3 to 8 hours to obtain phenylene-bisbenzimidazole.

[0027] In one embodiment, in step S20:

[0028] The phenylene-bisbenzimidazole and the sulfonating agent are mixed in a dropwise manner, the mixing time is 30 to 300 minutes, and the mixing temperature is 60 to 90° C.;

[0029] After the mixing is completed, a sulfonation reaction is carried out at 80-160° C. for 4-20 hours to obtain a sulfonic acid derivative of phenylene-bisbenzimidazole.

[0030] In one embodiment, step S30 includes:

[0031] S31, mixing the sulfonic acid derivative of phenylene-bisbenzimidazole with a sodium salt solution to precipitate crystals to obtain a crude product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt;

[0032] S32, mixing the crude product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, water and sodium hydroxide until the solution is clear, adding activated carbon for adsorption, filtering, and obtaining a filtrate;

[0033] S33, acidifying the filtrate and eluting it with an eluent to obtain purified phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt.

[0034] In one embodiment, in step S33, the acid used for the acidification treatment includes at least one of sulfuric acid, hydrochloric acid and phosphoric acid; and / or,

[0035] In step S33, the eluent includes a sodium salt solution or an organic reagent, wherein the sodium salt aqueous solution includes at least one of an aqueous solution of sodium sulfate, an aqueous solution of sodium bisulfate, an aqueous solution of sodium sulfite and an aqueous solution of sodium chloride, and the alcohol includes methanol, ethanol, propanol or butanol; preferably, the eluent includes an aqueous solution of sodium sulfate, an aqueous solution of sodium chloride or ethanol.

[0036] In one embodiment, in step S20, the sulfonating agent includes at least one of sulfuric acid, chlorosulfonic acid and oleum; and / or,

[0037] In step S20, the molar ratio of the phenylene-bisbenzimidazole to the chlorosulfonic acid is 1:(1.0-2.0); and / or,

[0038] In step S30, the sodium salt in the sodium salt solution includes sodium sulfate, sodium chloride or sodium carbonate.

[0039] The present invention also provides a device for the synthesis method of the aforementioned phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, comprising:

[0040] A reaction device containing a solvent and reaction raw materials; and

[0041] A condensation component, the condensation component includes a condensation device and a water separation device connected in an upper and lower direction; wherein the condensation device is used to reduce the temperature of the evaporated solvent and change it from a gaseous state to a liquid state; the water separation device is used to separate the target solvent from the non-target solvent, and the water separation device is respectively connected to a reflux device and a recovery device, the reflux device is connected to the reaction device to return the cooled target solvent to the reaction device, and the recovery device is used to recover the non-target solvent.

[0042] The invention adopts a new path to synthesize phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, mixes terephthalaldehyde, a catalyst, a solvent and o-phenylenediamine for cyclization reaction, dissolves the o-phenylenediamine in a solvent and then adds the solvent, and reacts with the terephthalaldehyde under the catalytic action of the catalyst, thereby avoiding an excessively rapid increase in system temperature during the reaction, improving the safety of the reaction, solving the problem of high-temperature sublimation of o-phenylenediamine in the cyclization reaction, avoiding the loss of o-phenylenediamine raw materials, improving the utilization rate of o-phenylenediamine, and further improving the yield of the product; and also avoiding the blockage caused by the long-term attachment of o-phenylenediamine to the inner wall of a reaction kettle and a pipeline after sublimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0044] Figure 1 The HPLC chromatogram of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt prepared in Example 1 provided by the present invention;

[0045] Figure 2 This is a high performance liquid chromatogram of the standard product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt prepared in Example 1 provided by the present invention.

[0046] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0047] To make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme in the embodiment of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiment, it is carried out according to the normal conditions or the conditions recommended by the manufacturer. If the reagents or instruments used do not specify the manufacturer, they are all conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes, taking "A and / or B" as an example, including scheme A, or scheme B, or schemes that A and B meet at the same time. In addition, the technical schemes between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in the field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist, and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention.

[0048] Disodium phenyl dibenzimidazole tetrasulfonate, English name is DISODIUM PHENYL DIBENZIMIDAZOLETETRASULFONATE (DPDT), alias: sodium salt of phenylene dibenzimidazole sulfonate. DPDT is a water-soluble UVA protective agent with an absorption wavelength between 290-370nm and good light stability.

[0049] The main function of disodium phenyl dibenzimidazole tetrasulfonate in cosmetics and skin care products is a chemical sunscreen. It is non-comedogenic, has a low risk factor, is relatively safe, and can be used with confidence.

[0050] The industrial preparation method of disodium phenyl dibenzimidazole tetrasulfonate is generally to first add terephthalic acid to concentrated sulfuric acid, heat it, then add o-phenylenediamine for mixed reaction, finally add chlorosulfonic acid as a sulfonating agent, keep warm in one pot, and finally purify to obtain disodium phenyl dibenzimidazole tetrasulfonate. However, the current preparation method has a high reaction temperature in the chemical synthesis process, and is prone to produce a large amount of white smoke, which is relatively dangerous.

[0051] In view of this, the present invention provides a method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, comprising the following steps:

[0052] S10, mixing terephthalaldehyde, a catalyst, a solvent and o-phenylenediamine, and performing a cyclization reaction to obtain phenylene-bisbenzimidazole;

[0053] S20, mixing the phenylene-bisbenzimidazole with a sulfonating agent, and performing a sulfonation reaction to obtain a sulfonic acid derivative of the phenylene-bisbenzimidazole;

[0054] S30, mixing the sulfonic acid derivative of phenylene-bisbenzimidazole with a sodium salt solution to precipitate crystals to obtain phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt.

[0055] In the technical scheme of the present invention, a completely new path is adopted to synthesize phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, terephthalaldehyde, a catalyst, a solvent and o-phenylenediamine are mixed to carry out a cyclization reaction, so that an excessively rapid increase in the system temperature during the reaction process is avoided, the safety of the reaction is improved, and the high-temperature sublimation phenomenon of o-phenylenediamine in the cyclization reaction is solved, so that the loss of o-phenylenediamine raw materials is avoided, the utilization rate of o-phenylenediamine is improved, and the yield of the product is further improved; at the same time, the blockage phenomenon caused by the long-term attachment of o-phenylenediamine to the inner wall of the reactor and the pipeline after sublimation is also avoided.

[0056] The reaction principle of the present invention is as follows:

[0057] The chemical reaction equation of the cyclization reaction in step S10 is:

[0058]

[0059] The chemical reaction equation of the sulfonation reaction in step S20 is:

[0060]

[0061] The chemical reaction equation of the salt addition precipitation reaction in step S30 is:

[0062]

[0063] In some embodiments of the present invention, in step S10, the molar ratio of the terephthalaldehyde to the catalyst is 1:(0.5-2.0); and / or, the molar ratio of the terephthalaldehyde to the o-phenylenediamine is 1:(2.0-2.5); and / or, the mass ratio of the terephthalaldehyde to the solvent is 1:(8-30); and / or, the catalyst comprises sodium pyrosulfite, sodium sulfite or sulfur dioxide.

[0064] In the technical solution of the present invention, the molar ratio of the terephthalaldehyde to the catalyst can be 1:0.5, 1:1 or 1:2.0; the molar ratio of the terephthalaldehyde to the o-phenylenediamine can be 1:2.0, 1:2.2 or 1:2.5; the mass ratio of the terephthalaldehyde to the solvent can be 1:8, 1:20 or 1:30, and the molar ratio and mass ratio can ensure that the cyclization reaction is relatively sufficient within a suitable range. The catalyst can be sodium pyrosulfite, sodium sulfite or sulfur dioxide, and the above catalyst can catalyze the cyclization reaction of o-phenylenediamine and terephthalaldehyde, promote the reaction to proceed in the forward direction, make o-phenylenediamine and terephthalaldehyde react fully, and improve the yield of the intermediate phenylene-bisbenzimidazole.

[0065] In some embodiments of the present invention, step S10 comprises: adding terephthalaldehyde, a catalyst, and o-phenylenediamine to a solvent in sequence to carry out a cyclization reaction to obtain phenylene-bisbenzimidazole; wherein the solvent comprises water or an aqueous solution of alcohol; and the volume ratio of alcohol to water in the aqueous solution of alcohol is 1:(1-3).

[0066] In the technical scheme of the present invention, p-phenylenediamine, catalyst and o-phenylenediamine can be simultaneously put into the solvent in the form of solids for cyclization reaction, which will not cause the system temperature to be too high and produce a large amount of white smoke. When the solvent is water, the catalyst can be better dissolved; when the solvent is an aqueous solution of alcohol, the aqueous solution of alcohol can better dissolve terephthalaldehyde, catalyst and o-phenylenediamine, increase the dispersion uniformity of the raw materials, and make the cyclization reaction more sufficient and thorough. The volume ratio of alcohol and water in the aqueous solution of alcohol can be 1:1, 1:2 or 1:3. The volume ratio can ensure that terephthalaldehyde, catalyst and o-phenylenediamine in the reaction system are well dissolved in the solvent within a suitable range, increase the contact of the three raw materials, and promote the reaction to proceed fully. In addition, during the exothermic process of the cyclization reaction, as the temperature of the system increases, the alcohol in the aqueous solution of alcohol absorbs heat and refluxes. The refluxed alcohol will further dissolve the raw materials and reduce the system temperature, preventing o-phenylenediamine from sublimating, thereby reducing the loss of o-phenylenediamine and increasing the utilization rate, product purity and product yield of o-phenylenediamine.

[0067] It should be noted that, in the embodiment of the present invention, terephthalaldehyde and the catalyst may be dissolved in a solvent, and solid o-phenylenediamine may be added to the mixed solution.

[0068] In some embodiments of the present invention, step S10 includes:

[0069] S11, mixing terephthalaldehyde, a catalyst and a first solvent to obtain a first solution;

[0070] S12, mixing o-phenylenediamine and a second solvent to obtain a second solution;

[0071] S13, mixing the first solution and the second solution, and performing a cyclization reaction to obtain phenylene-bisbenzimidazole;

[0072] The boiling point of the first solvent and / or the second solvent is less than or equal to 100°C.

[0073] In the technical solution of the present invention, in step S11, terephthalaldehyde and the catalyst are dissolved in the first solvent together, and in step S12, the o-phenylenediamine solvent is dissolved in the second solvent, which can ensure that all raw materials are well dissolved and dispersed in the solvent. When the first solution and the second solution are mixed in step S13, the terephthalaldehyde, the catalyst and the o-phenylenediamine can be prevented from being locally contacted and causing intense heat release, thereby effectively reducing the danger of the exothermic process of the cyclization reaction. When the boiling point of the first solvent and / or the second solvent is less than or equal to 100° C., when the temperature of the reaction system reaches 100° C. or above, the first solvent and / or the second solvent will reflux, thereby reducing the temperature of the reaction system, thereby preventing the o-phenylenediamine from sublimating.

[0074] It should be noted that, in the scheme of the present invention, terephthalaldehyde, catalyst, and o-phenylenediamine may be dissolved in solvents separately and then mixed for reaction, such as dissolving terephthalaldehyde in alcohol, dissolving the catalyst in water, and dissolving o-phenylenediamine in alcohol, and then mixing the three mixed solutions for cyclization reaction.

[0075] In some embodiments of the present invention, in step S11, the mass ratio of the terephthalaldehyde to the first solvent is 1:(6-20); and / or, in step S12, the mass ratio of the o-phenylenediamine to the second solvent is 1:(2-10); and / or, in step S11, the first solvent comprises water or an aqueous solution of alcohol; the alcohol in the aqueous solution of alcohol comprises at least one of methanol and ethanol; and / or, in step S12, the second solvent comprises alcohol or an aqueous solution of alcohol; the alcohol and the alcohol in the aqueous solution of alcohol comprise at least one of methanol and ethanol.

[0076] In the technical solution of the present invention, the mass ratio of the terephthalaldehyde to the first solvent can be 1:6, 1:16, or 1:20, and the mass ratio can ensure that the terephthalaldehyde is fully dissolved within a suitable range; the mass ratio of the o-phenylenediamine to the second solvent can be 1:2, 1:6, or 1:10, and the mass ratio can ensure that the o-phenylenediamine is fully dissolved within a suitable range. The first solvent includes water or an aqueous solution of alcohol, and the second solvent includes alcohol or an aqueous solution of alcohol. The selection of the first solvent and the second solvent can ensure that the final system contains water and alcohol, water is used to dissolve the catalyst, and alcohol is used to dissolve terephthalaldehyde and o-phenylenediamine, and is also used for reflux.

[0077] When the first solvent is an aqueous solution of alcohol, the alcohol therein may be any one of methanol and ethanol, or may be methanol and ethanol, all within the protection scope of the present invention. The type of alcohol in the second solvent or in the aqueous solution of alcohol is the same. The water in the first solvent can dissolve the catalyst well; the alcohol in the second solvent can dissolve terephthalaldehyde and o-phenylenediamine well, and its reflux effect can also control the temperature of the reaction system well, cool the reaction system, and prevent violent boiling and sublimation of o-phenylenediamine.

[0078] In some embodiments of the present invention, step S13 includes: mixing the first solution and the second solution by dropwise addition, the mixing time is 30 to 300 minutes, the mixing temperature is 60 to 90°C, and after the mixing is completed, the cyclization reaction is carried out at 80 to 120°C for 3 to 8 hours to obtain phenylene-bisbenzimidazole.

[0079] In the technical scheme of the present invention, the time of dripping and mixing can be 30min, 150min or 300min, the mixing temperature can be 60℃, 70℃ or 90℃, and the cyclization reaction time can be 30min, 150min or 300min. The dripping time can better control the speed of the cyclization reaction by controlling the contact speed of o-phenylenediamine with terephthalaldehyde and the catalyst within a suitable range, so that the heat release is uniform and well controlled. For example, when the second solution is dripped into the first solution, the heat released by the reaction can be quickly absorbed by the solution, and the system temperature is maintained within a relatively low range, and it is not easy to cause violent boiling and sublimation of o-phenylenediamine; the mixing temperature can ensure the smooth progress of the cyclization reaction within a suitable range; the cyclization reaction time can ensure a more thorough reaction within a suitable range, and the product yield is better.

[0080] In some embodiments of the present invention, in step S20:

[0081] The phenylene-bisbenzimidazole and the sulfonating agent are mixed in a dropwise manner, the mixing time is 30 to 300 minutes, and the mixing temperature is 60 to 90° C.;

[0082] After the mixing is completed, a sulfonation reaction is carried out at 80-160° C. for 4-20 hours to obtain a sulfonic acid derivative of phenylene-bisbenzimidazole.

[0083] In the technical solution of the present invention, the time of dripping and mixing in step S20 can be 30 minutes, 150 minutes or 300 minutes, the mixing temperature can be 60° C., 70° C. or 90° C., the temperature of the sulfonation reaction can be 80° C., 120° C. or 160° C., and the sulfonation reaction time can be 4 hours, 12 hours or 20 hours. The above conditions can ensure sufficient mixing and a thorough sulfonation reaction within a suitable range.

[0084] In some embodiments of the present invention, step S30 includes:

[0085] S31, mixing the sulfonic acid derivative of phenylene-bisbenzimidazole with a sodium salt solution to precipitate crystals to obtain a crude product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt;

[0086] S32, mixing the crude product of disodium phenylene-bisbenzimidazole-tetrasulfonic acid salt, water and an alkaline substance until the solution is clear, adding activated carbon for adsorption, filtering, and obtaining a filtrate;

[0087] S33, acidifying the filtrate and eluting it with an eluent to obtain purified phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt.

[0088] In the technical scheme of the present invention, in step S31, the sulfonic acid derivative of phenylene-bisbenzimidazole is mixed with a sodium salt solution, so that the sulfonic acid derivative of phenylene-bisbenzimidazole is converted into phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, and since the solubility of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt is low, it precipitates from the solution into crystals. In step S32, the crude product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt is mixed with water and sodium hydroxide until the solution is clarified, so that the disodium salt of phenylene-bisbenzimidazole-tetrasulfonic acid is converted into phenylene-bisbenzimidazole-tetrasulfonic acid tetrasodium salt, and since phenylene-bisbenzimidazole-tetrasulfonic acid tetrasodium salt is easily soluble in water, adding activated carbon is easy to adsorb impurities in the crude product. In step S33, the filtrate is acidified to convert phenylene-bisbenzimidazole-tetrasulfonic acid tetrasodium salt into phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt and precipitate, thereby obtaining a purified product and improving the purity of the product.

[0089] In some embodiments of the present invention, in step S33, the acid used for the acidification treatment includes at least one of sulfuric acid, hydrochloric acid and phosphoric acid. The above acids are widely available and have low costs.

[0090] In some embodiments of the present invention, in step S33, the eluent includes a sodium salt solution or an alcohol, wherein the sodium salt solution includes at least one of an aqueous solution of sodium sulfate, an aqueous solution of sodium bisulfate, an aqueous solution of sodium sulfite and an aqueous solution of sodium chloride, and the mass concentration of the sodium salt solution is 2% to 3%; the alcohol includes methanol, ethanol, propanol or butanol; preferably, the eluent includes an aqueous solution of sodium sulfate, an aqueous solution of sodium chloride or ethanol. The crystal form of the purified disodium phenylene-bisbenzimidazole-tetrasulfonic acid salt obtained by selecting the above eluent is better. More preferably, when the eluent is an alcohol, the crystal form of the obtained product is better and the particles are distinct.

[0091] In some embodiments of the present invention, in step S20, the sulfonating agent includes at least one of sulfuric acid, chlorosulfonic acid and fuming sulfuric acid; and / or, in step S20, the molar ratio of the phenylene-bisbenzimidazole to the chlorosulfonic acid is 1:(1.0-2.0); and / or, in step S30, the sodium salt in the sodium salt solution includes sodium sulfate, sodium chloride or sodium carbonate.

[0092] In the technical solution of the present invention, the molar ratio of the phenylene-bisbenzimidazole to the chlorosulfonic acid can be 1:1.0, 1:1.5 or 1:2.0. The molar ratio within a suitable range can ensure a more thorough sulfonation reaction.

[0093] The present invention also provides a device used in the synthesis method of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, including: a reaction device, the reaction device is filled with a solvent and a reaction raw material; and a condensation component, the condensation component includes a condensation device and a water separator connected in an up-down direction; wherein the condensation device is used to reduce the temperature of the evaporated solvent and change it from a gaseous state to a liquid state; the water separator is used to separate the target solvent from the non-target solvent, and the water separator is respectively connected to a reflux device and a recovery device, the reflux device is connected to the reaction device, and is used to return the cooled target solvent to the reaction device, and the recovery device is used to recover the non-target solvent. Wherein, the condensation component is used to control the condensation and reflux of low-boiling point substances in the solvent to reduce the temperature of the reaction system; specifically, the condensation component can include a condenser and a water separator connected in an up-down direction, and the side wall and the bottom of the water separator are respectively connected to a reflux bottle and a recovery bottle.

[0094] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0095] Example 1

[0096] A method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt comprises the following steps:

[0097] (1) Cyclization reaction: 5 mol of terephthalaldehyde, 5 mol of sodium pyrosulfite and 10 kg of water (first solvent) were added to a dry and clean reactor, and the mixture was heated to 70°C and stirred to mix evenly; 10 mol of o-phenylenediamine, 5 kg of ethanol and 5 kg of water (i.e., an aqueous solution of ethanol, second solvent) were added to a dry and clean dissolving reactor, and the mixture was stirred and heated to 70°C to dissolve the materials; the o-phenylenediamine solution after dissolution was added dropwise at 70°C for 2 hours, and the reaction was carried out at 80°C for 6 hours; the temperature was lowered to 20-30°C, and the crude product was filtered; the crude product was filtered, and 10 kg of water was added to make pulp; the wet product was filtered, and dried at 80°C at -0.1 MPa to obtain 1.522 kg of yellow powder, i.e., phenylene-bisbenzimidazole, with a yield of 98%.

[0098] (2) Sulfonation reaction: 1.522 kg of phenylene-bisbenzimidazole and 5 kg of sulfuric acid were added to the reaction flask, stirred and heated to 80°C; chlorosulfonic acid was added dropwise, and the reaction was completed after about 2 hours of addition, and the sulfonation reaction was carried out at 110°C for 8 hours.

[0099] (3) Precipitation and purification by salting: After the heat preservation is completed, the reaction solution is added dropwise to 15 kg of water to dissolve; 0.5 kg of sodium sulfate is added to the reaction solution to precipitate a crude product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt; filtered to obtain 4.7 kg of a wet product; the wet product is added to 5 kg of water, and 1 kg of a 30% sodium hydroxide aqueous solution is added dropwise to adjust the solution pH to 12 to dissolve the wet product; 0.2 kg of activated carbon is added for decolorization for 1 hour; the activated carbon is filtered, and 30% sulfuric acid is added dropwise to the filtrate to adjust the pH to 1 to precipitate crystals; filtered to obtain a light yellow solid wet product, and 0.6 kg of ethanol is added for rinsing once; 4.3 kg of a light yellow wet product is obtained; 80°C, -0.1 MPa vacuum drying is performed to obtain 3.214 kg of a yellow powder, i.e., phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, with a yield of 95% and a purity of 98.50%.

[0100] Example 2

[0101] Compared with Example 1, Example 2 is different in that:

[0102] In step (1): sodium pyrosulfite is replaced by sulfur dioxide, the molar ratio of terephthalaldehyde to sulfur dioxide is 1:0.5; the molar ratio of terephthalaldehyde to o-phenylenediamine is 1:2.3; the mass ratio of terephthalaldehyde to water (first solvent) is 1:20; the mass ratio of o-phenylenediamine to methanol solution (second solvent) is 1:5, and the mass ratio of methanol to water in the methanol solution is 1:1.5; the reaction is added dropwise at 60°C for 30 minutes, and the reaction is carried out at 70°C for 8 hours;

[0103] In step (2), chlorosulfonic acid is added dropwise at 60° C. for 30 min; and the sulfonation reaction is carried out at 80° C. for 4 h.

[0104] The yield of phenylene-bisbenzimidazole obtained in Example 2 was 96.23%; the yield of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was 92.16% and the purity was 97.50%.

[0105] Example 3

[0106] Compared with Example 1, Example 3 is different in that:

[0107] In step (1), sodium pyrosulfite is replaced by sodium sulfite, the molar ratio of terephthalaldehyde to sodium sulfite is 1:2; the molar ratio of terephthalaldehyde to o-phenylenediamine is 1:2.5; the mass ratio of terephthalaldehyde to water (first solvent) is 1:6; the mass ratio of o-phenylenediamine to ethanol solution (second solvent) is 1:2, and the mass ratio of ethanol to water in the ethanol solution is 1:2; the reaction is added dropwise at 90°C for 300 minutes, and the cyclization reaction is carried out at 120°C for 3 hours;

[0108] In step (2), chlorosulfonic acid is added dropwise at 90° C. for 300 min; and the sulfonation reaction is carried out at 160° C. for 20 h.

[0109] The yield of phenylene-bisbenzimidazole obtained in Example 3 was 96.16%; the yield of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was 92.13% and the purity was 97.80%.

[0110] Example 4

[0111] Compared with Example 1, Example 4 is different in that:

[0112] In step (1), terephthalaldehyde, sodium metabisulfite and an aqueous solution of ethanol are added to a dry and clean reactor in sequence, and the temperature is raised to 70° C. and stirred to mix evenly; solid o-phenylenediamine is then added, and the feeding time is 2 hours. After the feeding, the temperature is kept at 80° C. for cyclization reaction for 6 hours; the mass ratio of terephthalaldehyde to the ethanol solution is 1:8; and the mass ratio of ethanol to water in the ethanol solution is 1:2.

[0113] The yield of phenylene-bisbenzimidazole obtained in Example 4 was 97.33%; the yield of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was 94.24% and the purity was 98.20%.

[0114] Example 5

[0115] Compared with Example 4, Example 5 is different in that:

[0116] In step (1), the mass ratio of terephthalaldehyde to the ethanol solution is 1:30; the mass ratio of ethanol to water in the ethanol solution is 1:3.

[0117] The yield of phenylene-bisbenzimidazole obtained in Example 5 was 97.26%; the yield of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was 94.31% and the purity was 98.10%.

[0118] Example 6

[0119] Compared with Example 4, Example 6 is different in that:

[0120] In step (1), the mass ratio of terephthalaldehyde to the ethanol solution is 1:20; the mass ratio of ethanol to water in the ethanol solution is 1:2.5.

[0121] The yield of phenylene-bisbenzimidazole obtained in Example 6 was 97.14%; the yield of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was 94.17% and the purity was 98.10%.

[0122] Example 7

[0123] Compared with Example 4, Example 7 is different in that:

[0124] In step (1): replace the ethanol solution with water.

[0125] The yield of phenylene-bisbenzimidazole obtained in Example 7 was 96.31%; the yield of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was 93.35% and the purity was 98.00%.

[0126] In the above-mentioned Examples 1 to 7, the method for detecting the purity of the product is high performance liquid chromatography, and the yield calculation formula is: yield = (actual amount of target product produced / theoretical amount of target product produced) × 100%.

[0127] Comparative Example 1

[0128] This comparative example 1 provides a prior art, and the specific steps are as follows:

[0129] First, 1.703 g of 96% sulfuric acid and 232 g of terephthalic acid were added to a reactor, and then 302 g of o-phenylenediamine was added after stirring to react. During the process, the temperature of the reaction system was raised to 110° C. After the reaction was completed, 1200 g of chlorosulfonic acid was continued to be added to the reaction system, and the mixture was stirred for another 12 h at 110° C. for sulfonation reaction. After the reaction was completed, the reaction system was cooled to room temperature, and then 4000 g of water and 600 g of 13% sodium chloride were added and mixed, and the mixture was stirred at 47° C. for 2 h and then filtered. The filter cake was washed with a 5 wt % sodium chloride solution to obtain 782.1 g of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt;

[0130] The generated phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was mixed with 168 g of 45% sodium hydroxide solution and 2000 g of water until the phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was dissolved, and then 30 g of activated carbon was added for adsorption for 5 hours and filtered. The pH of the filtrate was adjusted to 3, stirred for 2 hours and then filtered. The filter cake was washed with 2% sodium chloride solution to obtain 664.8 g of finished phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt.

[0131] During the reaction, when o-phenylenediamine is added to the reactor, it reacts with concentrated sulfuric acid to generate o-phenylenediamine sulfate, causing the o-phenylenediamine solid to aggregate, and the dissolved o-phenylenediamine participates in the cyclization reaction, resulting in a large amount of heat release. The heat causes the undissolved o-phenylenediamine solid to sublimate and generate a large amount of white smoke, resulting in waste, resulting in a low utilization rate of o-phenylenediamine, and the yield is only 70.18%, and the purity is 98%.

[0132] Performance Testing

[0133] The phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt prepared in Example 1 was subjected to high performance liquid chromatography analysis. The results are as follows: Figure 1 As shown in Table 1. The standard product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt was subjected to high performance liquid chromatography analysis. The results are as follows Figure 2 And as shown in Table 2.

[0134] Depend on Figure 1 It can be seen that the peak with a retention time of 6.852 is the product peak, which is different from the standard product (such as Figure 2 The peak positions of the two samples are basically the same.

[0135] Table 1 HPLC test table of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt finished product

[0136]

[0137] Table 2 High performance liquid chromatography test table of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt standard product

[0138]

[0139] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, characterized in that: The following steps are involved: S10, mixing terephthalaldehyde, a catalyst, a solvent and o-phenylenediamine, and performing a cyclization reaction to obtain phenylene-bisbenzimidazole; S20, mixing the phenylene-bisbenzimidazole with a sulfonating agent, and performing a sulfonation reaction to obtain a sulfonic acid derivative of the phenylene-bisbenzimidazole; S30, mixing the sulfonic acid derivative of phenylene-bisbenzimidazole with a sodium salt solution to precipitate crystals to obtain phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt.

2. The method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt as claimed in claim 1, characterized in that: In step S10: The molar ratio of the terephthalaldehyde to the catalyst is 1:(0.5-2.0); and / or, The molar ratio of the terephthalaldehyde to the o-phenylenediamine is 1:(2.0-2.5); and / or, The mass ratio of the terephthalaldehyde to the solvent is 1:(8-30); and / or, The catalyst includes sodium metabisulfite, sodium sulfite or sulfur dioxide.

3. The synthetic method of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt as claimed in claim 2, characterized in that, Step S10 includes: Terephthalaldehyde, a catalyst and o-phenylenediamine are sequentially added into a solvent to carry out a cyclization reaction to obtain phenylene-bisbenzimidazole; wherein the solvent comprises water or an aqueous solution of alcohol, and the volume ratio of alcohol to water in the aqueous solution of alcohol is 1:(1-3).

4. The method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt as claimed in claim 1, characterized in that: Step S10 includes: S11, mixing terephthalaldehyde, a catalyst and a first solvent to obtain a first solution; S12, mixing o-phenylenediamine and a second solvent to obtain a second solution; S13, mixing the first solution and the second solution, and performing a cyclization reaction to obtain phenylene-bisbenzimidazole; The boiling point of the first solvent and / or the second solvent is less than or equal to 100°C.

5. The method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt as claimed in claim 4, characterized in that: In step S11, the mass ratio of the terephthalaldehyde to the first solvent is 1:(6-20); and / or, In step S12, the mass ratio of the o-phenylenediamine to the second solvent is 1:(2-10); and / or, In step S11, the first solvent includes water or an aqueous solution of alcohol; the alcohol in the aqueous solution of alcohol includes at least one of methanol and ethanol; and / or, In step S12, the second solvent includes alcohol or an aqueous solution of alcohol; the alcohol in the alcohol and the aqueous solution of alcohol includes at least one of methanol and ethanol; Step S13 comprises: mixing the first solution and the second solution by dropwise addition, the mixing time is 30 to 300 minutes, the mixing temperature is 60 to 90° C., and after the mixing is completed, performing a cyclization reaction at 80 to 120° C. for 3 to 8 hours to obtain phenylene-bisbenzimidazole.

6. The method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt as claimed in claim 1, characterized in that: In step S20: The phenylene-bisbenzimidazole and the sulfonating agent are mixed in a dropwise manner, the mixing time is 30 to 300 minutes, and the mixing temperature is 60 to 90° C.; After the mixing is completed, a sulfonation reaction is carried out at 80-160° C. for 4-20 hours to obtain a sulfonic acid derivative of phenylene-bisbenzimidazole.

7. The method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt as claimed in claim 1, characterized in that: Step S30 includes: S31, mixing the sulfonic acid derivative of phenylene-bisbenzimidazole with a sodium salt solution to precipitate crystals to obtain a crude product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt; S32, mixing the crude product of phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt, water and sodium hydroxide until the solution is clear, adding activated carbon for adsorption, filtering, and obtaining a filtrate; S33, acidifying the filtrate and eluting it with an eluent to obtain purified disodium phenylene-bisbenzimidazole-tetrasulfonic acid salt.

8. The method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt as claimed in claim 7, characterized in that: In step S33, the acid used for the acidification treatment includes at least one of sulfuric acid, hydrochloric acid and phosphoric acid; and / or, In step S33, the eluent includes a sodium salt solution or an alcohol, wherein the sodium salt solution includes at least one of an aqueous solution of sodium sulfate, an aqueous solution of sodium bisulfate, an aqueous solution of sodium sulfite and an aqueous solution of sodium chloride, and the alcohol includes methanol, ethanol, propanol or butanol; preferably, the eluent includes an aqueous solution of sodium sulfate, an aqueous solution of sodium chloride or ethanol.

9. The method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt as claimed in claim 1, characterized in that: In step S20, the sulfonating agent includes at least one of sulfuric acid, chlorosulfonic acid and oleum; and / or, In step S20, the molar ratio of the phenylene-bisbenzimidazole to the chlorosulfonic acid is 1:(1.0-2.0); and / or, In step S30, the sodium salt in the sodium salt solution includes sodium sulfate, sodium chloride or sodium carbonate.

10. A device for use in the method for synthesizing phenylene-bisbenzimidazole-tetrasulfonic acid disodium salt according to any one of claims 1 to 9, characterized in that: include: A reaction device, wherein the reaction device contains a solvent and reaction raw materials; as well as, A condensation component, the condensation component includes a condensation device and a water separation device connected in an upper and lower direction; wherein the condensation device is used to reduce the temperature of the evaporated solvent and change it from a gaseous state to a liquid state; the water separation device is used to separate the target solvent from the non-target solvent, and the water separation device is respectively connected to a reflux device and a recovery device, the reflux device is connected to the reaction device to return the cooled target solvent to the reaction device, and the recovery device is used to recover the non-target solvent.

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