CN115286593A - Preparation method of rubber vulcanization accelerator dibenzothiazyl disulfide - Google Patents
Preparation method of rubber vulcanization accelerator dibenzothiazyl disulfide Download PDFInfo
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- AFZSMODLJJCVPP-UHFFFAOYSA-N dibenzothiazol-2-yl disulfide Chemical compound C1=CC=C2SC(SSC=3SC4=CC=CC=C4N=3)=NC2=C1 AFZSMODLJJCVPP-UHFFFAOYSA-N 0.000 title claims abstract description 56
- 238000002360 preparation method Methods 0.000 title claims abstract description 12
- 238000013040 rubber vulcanization Methods 0.000 title claims abstract description 10
- 238000006243 chemical reaction Methods 0.000 claims abstract description 46
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 38
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 26
- 239000003960 organic solvent Substances 0.000 claims abstract description 17
- 239000012046 mixed solvent Substances 0.000 claims abstract description 5
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 98
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 56
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical group OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 54
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 claims description 44
- 238000003756 stirring Methods 0.000 claims description 40
- 229910052757 nitrogen Inorganic materials 0.000 claims description 28
- LCPVQAHEFVXVKT-UHFFFAOYSA-N 2-(2,4-difluorophenoxy)pyridin-3-amine Chemical compound NC1=CC=CN=C1OC1=CC=C(F)C=C1F LCPVQAHEFVXVKT-UHFFFAOYSA-N 0.000 claims description 26
- CHQMHPLRPQMAMX-UHFFFAOYSA-L sodium persulfate Substances [Na+].[Na+].[O-]S(=O)(=O)OOS([O-])(=O)=O CHQMHPLRPQMAMX-UHFFFAOYSA-L 0.000 claims description 26
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical group COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 claims description 22
- 235000019253 formic acid Nutrition 0.000 claims description 22
- YXIWHUQXZSMYRE-UHFFFAOYSA-N 1,3-benzothiazole-2-thiol Chemical compound C1=CC=C2SC(S)=NC2=C1 YXIWHUQXZSMYRE-UHFFFAOYSA-N 0.000 claims description 20
- 239000000203 mixture Substances 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 16
- 239000007789 gas Substances 0.000 claims description 15
- 239000003054 catalyst Substances 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000007800 oxidant agent Substances 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 10
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 9
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 9
- 239000003638 chemical reducing agent Substances 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 8
- WIWBLJMBLGWSIN-UHFFFAOYSA-L dichlorotris(triphenylphosphine)ruthenium(ii) Chemical group [Cl-].[Cl-].[Ru+2].C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1 WIWBLJMBLGWSIN-UHFFFAOYSA-L 0.000 claims description 8
- 230000001590 oxidative effect Effects 0.000 claims description 7
- 239000011261 inert gas Substances 0.000 claims description 6
- 239000008096 xylene Substances 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 2
- 238000002844 melting Methods 0.000 abstract description 25
- 230000008018 melting Effects 0.000 abstract description 25
- 230000003647 oxidation Effects 0.000 abstract description 16
- 239000002994 raw material Substances 0.000 abstract description 7
- 230000009467 reduction Effects 0.000 abstract description 6
- 239000000843 powder Substances 0.000 description 18
- 239000012535 impurity Substances 0.000 description 16
- 239000007864 aqueous solution Substances 0.000 description 14
- 238000004128 high performance liquid chromatography Methods 0.000 description 14
- 238000001514 detection method Methods 0.000 description 13
- 239000012065 filter cake Substances 0.000 description 13
- 238000010992 reflux Methods 0.000 description 13
- 229910001220 stainless steel Inorganic materials 0.000 description 13
- 239000010935 stainless steel Substances 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 238000006722 reduction reaction Methods 0.000 description 7
- 238000005303 weighing Methods 0.000 description 6
- SUCQPHMWFOCTTR-UHFFFAOYSA-L dichlororuthenium;triphenylphosphane Chemical compound Cl[Ru]Cl.C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1 SUCQPHMWFOCTTR-UHFFFAOYSA-L 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 238000010531 catalytic reduction reaction Methods 0.000 description 4
- 239000012043 crude product Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 239000012279 sodium borohydride Substances 0.000 description 4
- 229910000033 sodium borohydride Inorganic materials 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 description 2
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- RXCMFQDTWCCLBL-UHFFFAOYSA-N 4-amino-3-hydroxynaphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(N)=C(O)C=C(S(O)(=O)=O)C2=C1 RXCMFQDTWCCLBL-UHFFFAOYSA-N 0.000 description 1
- SWDNOTOAPKVHPN-UHFFFAOYSA-N C(C=C1)=CC=C1P(C1=CC=CC=C1)C1=CC=CC=C1.C(C=C1)=CC=C1P(C1=CC=CC=C1)C1=CC=CC=C1.C(C=C1)=CC=C1P(C1=CC=CC=C1)C1=CC=CC=C1.Cl.Cl Chemical compound C(C=C1)=CC=C1P(C1=CC=CC=C1)C1=CC=CC=C1.C(C=C1)=CC=C1P(C1=CC=CC=C1)C1=CC=CC=C1.C(C=C1)=CC=C1P(C1=CC=CC=C1)C1=CC=CC=C1.Cl.Cl SWDNOTOAPKVHPN-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000004042 decolorization Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000012429 reaction media Substances 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 235000010288 sodium nitrite Nutrition 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 125000003944 tolyl group Chemical group 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D277/00—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings
- C07D277/60—Heterocyclic compounds containing 1,3-thiazole or hydrogenated 1,3-thiazole rings condensed with carbocyclic rings or ring systems
- C07D277/62—Benzothiazoles
- C07D277/68—Benzothiazoles with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2
- C07D277/70—Sulfur atoms
- C07D277/76—Sulfur atoms attached to a second hetero atom
- C07D277/78—Sulfur atoms attached to a second hetero atom to a second sulphur atom
Abstract
The invention provides a preparation method of rubber vulcanization accelerator dibenzothiazyl disulfide, which takes crude M as a raw material, takes a mixed solvent of water and an organic solvent as a medium, and prepares high-purity dibenzothiazyl disulfide through reduction and decoloration reaction and two-stage oxidation, wherein the purity is over 99 percent, the free M is lower than 0.2 percent, and the melting point is more than or equal to 181 ℃.
Description
Technical Field
The invention relates to a preparation technology of fine chemicals, in particular to a preparation method of a rubber vulcanization accelerator, and specifically relates to a preparation method of a rubber vulcanization accelerator dibenzothiazyl disulfide.
Background
Dibenzothiazyl Disulfide (DM) is used as a main vulcanization accelerator which cannot be replaced at present in the rubber vulcanization accelerator industry, and the development of an environment-friendly process of the dibenzothiazyl Disulfide (DM) becomes the focus of the industry.
At present, in the production technology of rubber vulcanization accelerator dibenzothiazyl Disulfide (DM), 2-mercaptobenzothiazole (M) is taken as a raw material at home, and the following 2 production routes are mainly available.
(1) The two-step synthesis process comprises the following steps: (1) The 2-mercaptobenzothiazole crude product and alkaline compounds such as sodium hydroxide, ammonia water and the like form corresponding 2-mercaptobenzothiazole salt; (2) purifying by filtering, decoloring, extracting and the like; (3) The 2-mercaptobenzothiazole salt reacts with an oxidant to be oxidized to generate dibenzothiazyl Disulfide (DM).
The research of the process at present mainly focuses on the purification in the step (2) and the oxidation in the step (3). For example, in patent CN 107365281B, after 2-mercaptobenzothiazole is dissolved in ammonia water, insoluble substances are filtered, and under the action of a composite catalyst of urotropine and 1-amino-2-naphthol-4-sulfonic acid, a crude dibenzothiazyl disulfide is obtained by oxidation with hydrogen peroxide, and then the crude dibenzothiazyl disulfide is obtained by recrystallization with toluene or acetone.
The process has the following defects: (1) Because the crude M is not thoroughly refined, the DM product obtained by subsequent oxidation has low purity; (2) Acid is usually added at the same time when the 2-mercaptobenzothiazole salt is oxidized, so that partial 2-mercaptobenzothiazole salt reacts with acid to generate 2-mercaptobenzothiazole, and the free M in DM exceeds the standard; and (3) the operation is complex and has great potential safety hazard.
(2) The one-step synthesis process comprises the following steps: for example, in the Mengdong Master thesis "Key technology for the Industrial production of Dibenzothiazole Disulfide (DM) for pharmaceutical use", M is dissolved in TH solution, and then purified M is obtained by adding special activated carbon, boiling by heating, filtering, and recrystallizing, and then dissolved in a solvent, and then sodium nitrite and sulfuric acid are added, and oxygen is introduced for oxidation to obtain DM to be used. Further, as described in patent CN104592155A, 2-mercaptobenzothiazole (M) is oxidized in an organic solvent with hydrogen peroxide to obtain dibenzothiazyl Disulfide (DM).
The process has the following defects: (1) M purified by crude M is used as a raw material, but the oxidation difficulty of M is more difficult than that of M sodium salt or ammonium salt, so that complete oxidation is difficult generally; (2) The refining process of the crude product M is complicated, the refining difficulty is high, and more solid wastes are generated.
Disclosure of Invention
In order to overcome the technical defects in the prior art, the invention provides a preparation method of a rubber vulcanization accelerator dibenzothiazyl disulfide.
In order to achieve the purpose, the invention adopts the technical scheme that: a preparation method of a rubber vulcanization accelerator dibenzothiazyl disulfide comprises the following steps:
(1) Adding crude 2-mercaptobenzothiazole (crude M), a reducing agent and a catalyst into a pressure container by taking a mixed solvent of an organic solvent and water as a medium, and replacing air in a system by inert gas;
(2) Stirring and heating to a certain temperature for reaction for 1-2 h;
(3) Stirring and cooling to a certain temperature, and then replacing gas in the system with inert gas;
(4) Keeping the temperature and adding an oxidant to carry out a staged oxidation reaction;
(5) Separating and washing the mixture to obtain the high-quality dibenzothiazyl disulfide.
Preferably, the organic solvent is one or a mixture of benzene, toluene and xylene;
preferably, the inert gas is nitrogen;
preferably, the using amount of the organic solvent is 1-2 times of the mass of the crude M, and the using amount of the water is 5-10 times of the mass of the crude M;
preferably, the reducing agent is formic acid, and the dosage of the reducing agent is 5-10% of the mass of the crude M;
preferably, the catalyst is dichlorotris (triphenylphosphine) ruthenium, and the dosage of the catalyst is 0.1-0.5% of the mass of the crude M;
preferably, the stirring and heating to a certain temperature refers to heating to 172-180 ℃;
preferably, the temperature is reduced to 70-80 ℃;
preferably, the oxidizing agent is hydrogen peroxide and sodium persulfate;
preferably, the staged oxidation reaction is a two-stage oxidation reaction, namely, firstly adding hydrogen peroxide for oxidation, and then adding sodium persulfate for further oxidation;
preferably, the molar ratio of M to hydrogen peroxide to sodium persulfate is 1.0-0.6;
the invention has the following beneficial effects:
(1) selecting a mixed solvent of benzene, toluene, xylene and the like and water as a reaction medium, dissolving impurities in the crude M in an organic solvent, and dispersing undissolved M in water; the dissolution reduction reaction and the separation impurity removal are carried out under the high temperature condition, so that the solubility of the by-products in the organic phase is improved, and the consumption of the organic solvent is reduced.
(2) Formic acid is used as a reducing agent, a high-efficiency catalyst is screened out, indissolvable resin byproducts and colored impurities are transferred, catalytically reduced and dissolved in an organic solvent, and M cannot be reduced due to the weak reducing capacity of the formic acid, so that the complex operation steps of decolorization and adsorption impurity removal of the existing process are avoided, the process is simpler, and no additional waste such as activated carbon is generated; the by-product carbon dioxide after formic acid reduction can be directly discharged out of the system, thereby avoiding the defect that inorganic salts are additionally generated by using inorganic reducing agents (such as sodium sulfite and the like).
(3) Since the oxidizing agents hydrogen peroxide and sodium persulfate are both aqueous solutions and are insoluble in an organic solvent, the reaction for oxidizing M into dibenzothiazyl disulfide mainly occurs in a water system, and dibenzothiazyl disulfide solid is generated in water, so that impurities dissolved in the organic solvent are not included in the generated dibenzothiazyl disulfide solid, and a high-quality dibenzothiazyl disulfide product with high purity, high yield and white appearance can be obtained.
(4) The invention adopts two-stage oxidation, firstly, most M is oxidized into dibenzothiazyl disulfide by using a proper excess of green oxidant hydrogen peroxide, and simultaneously, a small amount of non-reducible colored impurities are further oxidized into soluble substances so as to be removed; the residual small amount of unreacted M is slightly stronger than sodium persulfate of hydrogen peroxide in oxidizing ability for further thorough oxidation, thereby obtaining the high-quality dibenzothiazyl disulfide with low free M.
In conclusion, the invention takes crude M as a raw material, takes a mixed solvent of water and an organic solvent as a medium, and prepares high-purity dibenzothiazyl disulfide through transfer catalytic reduction and two-stage oxidation, wherein the purity is more than 99 percent, the free M is less than 0.2 percent, and the melting point is more than or equal to 181 ℃. The method saves the refining step in the production of M while obtaining the high-purity dibenzothiazyl disulfide product, and has simple and convenient operation, thereby having higher economic benefit.
Detailed Description
The invention is further illustrated by the following specific examples.
Example 1
In the scheme, M is hydrogen peroxide: sodium persulfate molar ratio = 1.
37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of dichlorotris (triphenylphosphine) ruthenium are weighed and added into a stainless steel high-pressure reaction kettle, the air in a system is replaced by nitrogen, the temperature is raised to 172 ℃ under closed stirring, the temperature is reduced to 75 ℃ after stirring for 1 hour, the gas in the system is replaced by nitrogen, a condenser is opened for reflux, 47.6g of hydrogen peroxide (with the mass content of 10%) is slowly added into the reaction kettle for about 6 hours, and then 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) is continuously added, and the addition is completed within about 2 hours. After the addition, the stirring is closed, the mixture is filtered, filter cake is washed by toluene for 1 time and then washed by water for 2 times, and the white dibenzothiazyl disulfide powder 32.31g is obtained after drying, the purity of HPLC detection is 99.34 percent, the free M is 0.04 percent, the melting point is 182.6 ℃, and the yield is 97.17 percent.
Example 2
This example was carried out on the basis of example 1, with the formic acid content increased to 10% of the crude M, and without otherwise changing the conditions.
37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water, 3.72g of formic acid (with the content of 88%) and 0.04g of ruthenium triphenylphosphine dichloride (with the content of 10%) are weighed and added into a stainless steel high-pressure reaction kettle, air in a nitrogen replacement system is stirred in a closed manner and heated to 172 ℃, the temperature is reduced to 75 ℃ after stirring for reaction for 1h, gas in the nitrogen replacement system is cooled to 75 ℃, a condenser is opened for reflux, 47.6g of hydrogen peroxide (with the mass content of 10%) is slowly injected into the reaction kettle for about 6h, and then 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) is continuously injected, and the addition is completed within about 2h. After the addition, the stirring is closed, the mixture is filtered, filter cake is washed by toluene for 1 time and then washed by water for 2 times, and the white dibenzothiazyl disulfide powder 32.29g is obtained after drying, the purity of HPLC detection is 99.38%, the free M is 0.05%, the melting point is 182.7 ℃, and the yield is 97.11%.
On the basis of the embodiment 1, the dosage of the reducing agent is increased, the purity of the dibenzothiazyl disulfide is improved, and the yield is reduced, because the reduction reaction of insoluble impurities in the organic solvent is more thorough and the insoluble impurities are more thoroughly removed.
Example 3
This example was carried out under conditions in which the amount of sodium persulfate to be used was increased to 0.035 based on example 1 and the other conditions were maintained.
37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of ruthenium triphenylphosphine dichloride (with the content of 10%) are weighed and added into a stainless steel high-pressure reaction kettle, air in a nitrogen replacement system is stirred in a closed manner and heated to 172 ℃, the temperature is reduced to 75 ℃ after stirring for reaction for 1h, gas in the nitrogen replacement system is cooled to 75 ℃, a condenser is opened for reflux, 47.6g of hydrogen peroxide (with the mass content of 10%) is slowly injected into the reaction kettle for about 6h, and then 33.33g of sodium persulfate aqueous solution (with the mass content of 5%) is continuously injected, and the addition is completed within about 2h. After the addition, the stirring is closed, the mixture is filtered, filter cake is washed by toluene for 1 time and then washed by water for 2 times, and the white dibenzothiazyl disulfide powder 32.58g is obtained after drying, the purity of HPLC detection is 99.52 percent, the free M is 0.02 percent, the melting point is 183.5 ℃, and the yield is 97.99 percent.
Based on the example 1, the dosage of sodium persulfate di-oxidation is increased, and more organic solvent and undissolved M are oxidized into products, so that the yield, the purity and the melting point are greatly improved, and the content of free M is further reduced.
Example 4
This example was carried out under the same conditions as example 1 except that the toluene was changed to xylene.
Weighing 37.17g of crude M (with the content of 90%), 74.34g of dimethylbenzene, 186g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of ruthenium (triphenylphosphine) dichloride, adding the materials into a stainless steel high-pressure reaction kettle, replacing air in a system with nitrogen, stirring the materials, heating the materials to 172 ℃, stirring the materials for reaction for 1 hour, cooling the materials to 75 ℃, replacing gas in the system with nitrogen, opening a condenser for reflux, slowly pumping 47.6g of hydrogen peroxide (with the mass content of 10%) into the reaction kettle for about 6 hours, then continuously pumping 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) into the reaction kettle, and completing the pumping for about 2 hours. After the addition, the stirring is closed, the mixture is filtered, filter cakes are washed by dimethylbenzene for 1 time and then washed by water for 2 times, and the white dibenzothiazyl disulfide powder is dried to obtain 32.61g, the purity of which is 99.21 percent by HPLC detection, the free M is 0.05 percent, the melting point is 181.9 ℃, and the yield is 98.07 percent.
In example 1, toluene was replaced with xylene, and the purity and melting point of dibenzothiazyl disulfide were slightly lowered, but the yield was improved.
Example 5
This example was carried out on the basis of example 1, increasing the amount of the catalyst ruthenium (tris (triphenylphosphine) dichloride to 0.5% by mass of the crude M, the other conditions remaining unchanged.
37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of dichlorotris (triphenylphosphine) ruthenium are weighed and added into a stainless steel high-pressure reaction kettle, the air in a system is replaced by nitrogen, the temperature is raised to 172 ℃ under closed stirring, the temperature is reduced to 75 ℃ after stirring for 1 hour, the gas in the system is replaced by nitrogen, a condenser is opened for reflux, 47.6g of hydrogen peroxide (with the mass content of 10%) is slowly added into the reaction kettle for about 6 hours, and then 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) is continuously added, and the addition is completed within about 2 hours. After the addition, the stirring is closed, the mixture is filtered, filter cake is washed by toluene for 1 time and then washed by water for 2 times, and the white dibenzothiazyl disulfide powder 32.27g is obtained after drying, the purity of HPLC detection is 99.85 percent, the free M is 0.03 percent, the melting point is 183.2 percent, and the yield is 97.05 percent.
In addition to example 1, the purity and melting point of dibenzothiazyl disulfide were slightly improved with an increase in the amount of catalyst used, but the yield was somewhat lowered.
Comparative example 1
This example was carried out in the same manner as example 1, except that formic acid and a catalyst were not added.
Weighing 37.17g of crude M (with the content of 90%), 74.34g of toluene and 186g of water, adding the raw materials into a stainless steel high-pressure reaction kettle, replacing air in a system with nitrogen, stirring in a closed manner, heating to 172 ℃, stirring for reaction for 1 hour, cooling to 75 ℃, replacing gas in the system with nitrogen, opening a condenser for refluxing, slowly adding 47.6g of hydrogen peroxide (with the mass content of 10%) into the reaction kettle for about 6 hours, then continuously adding 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) into the reaction kettle, and completing addition within about 2 hours. After the addition, the stirring is closed, the mixture is filtered, filter cakes are washed by toluene for 1 time and then washed by water for 2 times, and the yellow dibenzothiazyl disulfide powder is dried to obtain 34.65g, the purity of the yellow dibenzothiazyl disulfide powder is 98.56 percent by HPLC detection, the free M is 0.02 percent, the melting point is 176.1 ℃, and the yield is 97.78 percent.
Experiments show that colored impurities in the crude product M are difficult to completely dissolve without transfer catalytic reduction reaction, so that the product purity, the melting point and the appearance are poor, and although the yield is improved, the impurity removal is insufficient and the impurity content is high.
Comparative example 2
37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of dichlorotris (triphenylphosphine) ruthenium are weighed and added into a stainless steel high-pressure reaction kettle, the air in the system is replaced by nitrogen, the temperature is raised to 160 ℃ under closed stirring, the temperature is reduced to 75 ℃ after stirring for 1 hour, the gas in the system is replaced by nitrogen, a condenser is opened for reflux, 47.6g of hydrogen peroxide (with the mass content of 10%) is slowly added into the reaction kettle for about 6 hours, and then 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) is continuously added, and the addition is completed within about 2 hours. After the addition, the stirring is closed, the mixture is filtered, filter cake is washed by toluene for 1 time, then washed by water for 2 times and dried to obtain yellow dibenzothiazyl disulfide powder 32.35g, the purity of the yellow dibenzothiazyl disulfide powder is 99.11 percent by HPLC detection, the free M is 0.04 percent, the melting point is 182.0 ℃, and the yield is 97.29 percent.
Experiments show that the reaction temperature of the catalytic reduction is reduced to 160 ℃, the reduction capability of formic acid is reduced, and colored impurities in the crude product M are difficult to remove, so that the product has low purity, melting point and poor appearance.
Comparative example 3
37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of ruthenium triphenylphosphine dichloride (with the content of 10%) are weighed and added into a stainless steel high-pressure reaction kettle, air in a nitrogen replacement system is stirred in a closed manner and heated to 190 ℃, the temperature is reduced to 75 ℃ after stirring for reaction for 1h, gas in the nitrogen replacement system is cooled to 75 ℃, a condenser is opened for reflux, 47.6g of hydrogen peroxide (with the mass content of 10%) is slowly injected into the reaction kettle for about 6h, and then 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) is continuously injected, and the addition is completed within about 2h. After the addition, the stirring is closed, the mixture is filtered, filter cake is washed by toluene for 1 time, then washed by water for 2 times and dried to obtain 32.27g of white dibenzothiazyl disulfide powder, the purity of the white dibenzothiazyl disulfide powder is 99.11 percent by HPLC detection, the free M is 0.14 percent, the melting point is 182.0 ℃, and the yield is 97.05 percent.
32.31g, purity 99.34% by HPLC, free M0.04%, melting point 182.6 ℃ and yield 97.17%.
Experiments show that the temperature of the catalytic reduction reaction is increased to 190 ℃, the reduction capability of formic acid is too strong, the melting point of purity is reduced to a certain extent, and the content of free M is increased. This is because the M is partially reduced due to the excessively strong reducibility, and thus other insoluble impurities are formed during the subsequent oxidation, which results in a decrease in the purity of dibenzothiazyl disulfide, and the impurities consume part of the oxidizing agent, resulting in an insufficient amount of the oxidizing agent to completely oxidize M.
Comparative example 4
This example is based on example 1, with formic acid and catalyst replaced by sodium borohydride.
Weighing 37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water and 1.86g of sodium borohydride, adding the crude M, the toluene, the water and the sodium borohydride into a stainless steel high-pressure reaction kettle, replacing air in a system with nitrogen, stirring the mixture in a closed manner to raise the temperature to 172 ℃, stirring the mixture for reaction for 1 hour, then cooling the mixture to 75 ℃, replacing gas in the system with nitrogen, opening a condenser for reflux, slowly adding 47.6g of hydrogen peroxide (with the mass content of 10%) into the reaction kettle for about 6 hours, then continuously adding 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) into the reaction kettle, and completing the addition for about 2 hours. After the addition, the stirring is closed, the mixture is filtered, filter cakes are washed for 1 time by toluene and then washed for 2 times by water, and the white dibenzothiazyl disulfide powder 32.35g is obtained by drying, the purity of the white dibenzothiazyl disulfide powder is 97.24 percent by HPLC detection, the free M is 1.06 percent, the melting point is 175.3 percent, and the yield is 97.29 percent.
The results show that the melting point of the purity is reduced more and the content of free M is increased more by using sodium borohydride with stronger reducibility for reduction.
Comparative example 5
Weighing 37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of dichlorotris (triphenylphosphine) ruthenium, adding the raw materials into a stainless steel high-pressure reaction kettle, replacing air in a system with nitrogen, stirring and heating to 172 ℃, stirring and reacting for 1 hour, cooling to 75 ℃, replacing gas in the system with nitrogen, opening a condenser to reflux, slowly adding 47.6g of hydrogen peroxide (with the mass content of 10%) into the reaction kettle for about 6 hours, and continuing to perform heat preservation and reaction for 2 hours. Stirring is stopped, filtration is carried out, filter cake is washed by toluene for 1 time, then washed by water for 2 times and dried to obtain 32.56g of white dibenzothiazyl disulfide powder, the purity by HPLC detection is 94.86%, the free M is 5.03%, the melting point is 168.8 ℃, and the yield is 101.31%.
Experiments show that without the second stage sodium persulfate oxidation step, M is difficult to be completely oxidized into DM, so that the product purity, the melting point and the free M content are low.
Comparative example 6
Weighing 37.17g of crude M (with the content of 90%), 260.34g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of dichlorotris (triphenylphosphine) ruthenium, adding the raw materials into a stainless steel high-pressure reaction kettle, replacing air in the system with nitrogen, stirring in a closed manner, heating to 172 ℃, cooling to 75 ℃ after stirring for 1 hour, replacing gas in the system with nitrogen, opening a condenser for refluxing, slowly adding 47.6g of hydrogen peroxide (with the mass content of 10%) into the reaction kettle for about 6 hours, then continuously adding 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) into the reaction kettle, and completing addition within about 2 hours. After the addition, the stirring is closed, the filter cake is washed for 2 times by water and dried to obtain 35.99g of yellow-green dibenzothiazyl disulfide powder, the purity is 89.62 percent by HPLC detection, the free M is 10.26 percent, the melting point is 146.7 ℃, and the yield is 108.23 percent.
The dibenzothiazyl disulfide is synthesized directly by a crude M reaction without using an organic solvent, a large amount of impurities in the crude M remain in a product, and the M cannot be completely oxidized due to the influence of the impurities, so that the appearance, the purity and the melting point of the dibenzothiazyl disulfide are greatly reduced.
Comparative example 7
Weighing 37.17g of crude M (with the content of 90%), 260.34g of toluene, 1.86g of formic acid (with the content of 88%) and 0.04g of dichlorotris (triphenylphosphine) ruthenium, adding the crude M, the toluene, the formic acid and the ruthenium into a stainless steel high-pressure reaction kettle, replacing air in a system with nitrogen, stirring and heating to 172 ℃, cooling to 75 ℃ after stirring and reacting for 1 hour, replacing gas in the system with nitrogen, opening a condenser for refluxing, slowly adding 47.6g of hydrogen peroxide (with the mass content of 10%) into the reaction kettle for about 6 hours, then continuously adding 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) into the reaction kettle, and completing the addition for about 2 hours. After the addition, the stirring is closed, the mixture is filtered, filter cake is washed by toluene for 1 time, then washed by water for 2 times and dried to obtain 32.31g of white dibenzothiazyl disulfide powder, the purity of the white dibenzothiazyl disulfide powder is 99.04 percent by HPLC detection, the free M is 0.03 percent, the melting point is 180.1 percent, and the yield is 95.07 percent.
Although toluene is used as a solvent at the beginning of the reaction, hydrogen peroxide and sodium persulfate are both aqueous solutions, so that the amount of water is reduced and the amount of toluene is increased, a small amount of dibenzothiazyl disulfide is dissolved in the toluene, the yield is reduced, and the purity of the dibenzothiazyl disulfide is reduced due to the reduction of the amount of water.
Comparative example 8
37.17g of crude M (with the content of 90%), 74.34g of toluene, 186g of water, 1.86g of formic acid (with the content of 88%) and 0.04g of ruthenium triphenylphosphine dichloride (with the content of 10%) are weighed and added into a stainless steel high-pressure reaction kettle, air in a nitrogen replacement system is stirred in a closed manner and heated to 172 ℃, the temperature is reduced to 90 ℃ after stirring for reaction for 1h, gas in the nitrogen replacement system is cooled to 90 ℃, a condenser is opened for reflux, 47.6g of hydrogen peroxide (with the mass content of 10%) is slowly injected into the reaction kettle for about 6h, and then 23.81g of sodium persulfate aqueous solution (with the mass content of 5%) is continuously injected, and the addition is completed within about 2h. After the addition, the stirring is closed, the mixture is filtered, filter cakes are washed for 1 time by toluene and then washed for 2 times by water, and the mixture is dried to obtain light yellow dibenzothiazyl disulfide powder 32.42g, the purity of HPLC detection is 98.89%, the free M is 0.76%, the melting point is 179.7 ℃, and the yield is 97.50%.
The oxidation temperature is increased to 90 ℃, a small amount of DM is overoxidated due to the fact that the oxidation capacity of sodium persulfate is too strong when the temperature is increased, so that the appearance of dibenzothiazyl disulfide is yellow, meanwhile, the temperature is too high, the decomposition speed of hydrogen peroxide is accelerated, the using amount of an oxidant is slightly insufficient, and the content of free M is increased.
The above detailed description is intended to illustrate the present invention, not to limit the present invention, and any modifications and changes made within the spirit of the present invention and the scope of the claims fall within the scope of the present invention.
Claims (10)
1. A preparation method of a rubber vulcanization accelerator dibenzothiazyl disulfide is characterized by comprising the following steps:
(1) Adding crude 2-mercaptobenzothiazole (crude M), a reducing agent and a catalyst into a pressure container by taking a mixed solvent of an organic solvent and water as a medium, and replacing air in a system by inert gas;
(2) Stirring and heating to 172-180 ℃ for reaction for 1-2 h;
(3) Stirring and cooling to 70-80 ℃, and then replacing gas in the system with inert gas;
(4) Keeping the temperature and adding an oxidant to carry out a staged oxidation reaction;
(5) Separating and washing the mixture to obtain the high-quality dibenzothiazyl disulfide.
2. The preparation method according to claim 1, wherein the organic solvent is one or more of benzene, toluene and xylene.
3. The method according to claim 1, wherein the organic solvent is used in an amount of 1 to 2 times the mass of the crude M, and the water is used in an amount of 5 to 10 times the mass of the crude M.
4. The method according to claim 1, wherein the reducing agent is formic acid and is used in an amount of 5 to 10% by mass based on the crude M.
5. The process according to claim 1, wherein the catalyst is dichlorotris (triphenylphosphine) ruthenium in an amount of 0.1 to 0.5% by mass of the crude M.
6. The method of claim 1, wherein the inert gas is nitrogen.
7. The method according to claim 1, wherein the oxidizing agent is hydrogen peroxide and/or sodium persulfate.
8. The method according to claim 1, wherein the oxidation reaction is a two-stage oxidation reaction.
9. The preparation method according to claim 9, wherein the two-stage oxidation reaction is a first-stage oxidation reaction by adding hydrogen peroxide, and a second-stage oxidation reaction by adding sodium persulfate.
10. The preparation method according to claim 10, wherein the molar ratio of M, hydrogen peroxide and sodium persulfate is 1.0-0.6-0.7.
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| CN101693701A (en) * | 2009-10-21 | 2010-04-14 | 山东阳谷华泰化工股份有限公司 | Purification process for vulcanization accelerator 2-mercaptobenzothiazole |
| CN103193732A (en) * | 2013-04-25 | 2013-07-10 | 宝月（天津）环保工程有限公司 | Preparation method of rubber vulcanization accelerator DM |
| CN104230843A (en) * | 2014-08-29 | 2014-12-24 | 山东海迈新材料有限公司 | Process for sectional oxosynthesis of DM (dibenzothiazyl disulfide) |
| CN108610303A (en) * | 2018-08-08 | 2018-10-02 | 山东金城医药化工有限公司 | The synthetic method of dibenzothiazyl disulfide |
| CN111620836A (en) * | 2020-06-23 | 2020-09-04 | 河南省化工研究所有限责任公司 | Method for refining 2-mercaptobenzothiazole |
| CN112625002A (en) * | 2019-09-24 | 2021-04-09 | 河北合佳医药科技集团股份有限公司 | Preparation method of pharmaceutical-grade dibenzothiazyl disulfide |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101693701A (en) * | 2009-10-21 | 2010-04-14 | 山东阳谷华泰化工股份有限公司 | Purification process for vulcanization accelerator 2-mercaptobenzothiazole |
| CN103193732A (en) * | 2013-04-25 | 2013-07-10 | 宝月（天津）环保工程有限公司 | Preparation method of rubber vulcanization accelerator DM |
| CN104230843A (en) * | 2014-08-29 | 2014-12-24 | 山东海迈新材料有限公司 | Process for sectional oxosynthesis of DM (dibenzothiazyl disulfide) |
| CN108610303A (en) * | 2018-08-08 | 2018-10-02 | 山东金城医药化工有限公司 | The synthetic method of dibenzothiazyl disulfide |
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