CA1065320A - Preparation of 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole - Google Patents
Preparation of 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazoleInfo
- Publication number
- CA1065320A CA1065320A CA233,629A CA233629A CA1065320A CA 1065320 A CA1065320 A CA 1065320A CA 233629 A CA233629 A CA 233629A CA 1065320 A CA1065320 A CA 1065320A
- Authority
- CA
- Canada
- Prior art keywords
- amine
- benzothiazole
- methylpiperidine
- methylpiperidinothio
- group
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- JGCDEKLDKXSNJE-UHFFFAOYSA-N 2-(4-methylpiperidin-1-yl)sulfanyl-1,3-benzothiazole Chemical compound C1CC(C)CCN1SC1=NC2=CC=CC=C2S1 JGCDEKLDKXSNJE-UHFFFAOYSA-N 0.000 title claims abstract description 10
- 238000002360 preparation method Methods 0.000 title claims abstract description 10
- GQXVNLBNGZXTGJ-UHFFFAOYSA-N 2-(3-methylpiperidin-1-yl)sulfanyl-1,3-benzothiazole Chemical compound C1C(C)CCCN1SC1=NC2=CC=CC=C2S1 GQXVNLBNGZXTGJ-UHFFFAOYSA-N 0.000 title claims abstract description 9
- 150000001412 amines Chemical class 0.000 claims abstract description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 20
- 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 claims abstract description 18
- 238000006243 chemical reaction Methods 0.000 claims abstract description 9
- 239000012266 salt solution Substances 0.000 claims abstract description 7
- 238000000034 method Methods 0.000 claims description 27
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 24
- 239000000203 mixture Substances 0.000 claims description 23
- 239000007844 bleaching agent Substances 0.000 claims description 22
- 239000002002 slurry Substances 0.000 claims description 12
- JEGMWWXJUXDNJN-UHFFFAOYSA-N 3-methylpiperidine Chemical compound CC1CCCNC1 JEGMWWXJUXDNJN-UHFFFAOYSA-N 0.000 claims description 10
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 9
- QAZLUNIWYYOJPC-UHFFFAOYSA-M sulfenamide Chemical compound [Cl-].COC1=C(C)C=[N+]2C3=NC4=CC=C(OC)C=C4N3SCC2=C1C QAZLUNIWYYOJPC-UHFFFAOYSA-M 0.000 claims description 9
- UZOFELREXGAFOI-UHFFFAOYSA-N 4-methylpiperidine Chemical compound CC1CCNCC1 UZOFELREXGAFOI-UHFFFAOYSA-N 0.000 claims description 8
- -1 amine salt Chemical class 0.000 claims description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 3
- 238000013019 agitation Methods 0.000 claims description 2
- 125000001164 benzothiazolyl group Chemical group S1C(=NC2=C1C=CC=C2)* 0.000 claims description 2
- 238000011065 in-situ storage Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims 2
- 125000002467 phosphate group Chemical class [H]OP(=O)(O[H])O[*] 0.000 claims 2
- 238000001035 drying Methods 0.000 claims 1
- 238000005406 washing Methods 0.000 claims 1
- 239000000376 reactant Substances 0.000 abstract description 7
- 239000007800 oxidant agent Substances 0.000 abstract description 2
- 239000008187 granular material Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 239000000839 emulsion Substances 0.000 description 4
- 238000004073 vulcanization Methods 0.000 description 4
- PAMIQIKDUOTOBW-UHFFFAOYSA-N 1-methylpiperidine Chemical compound CN1CCCCC1 PAMIQIKDUOTOBW-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- OEZWWCFLLFPENR-UHFFFAOYSA-N 3-methylpiperidin-1-ium;sulfate Chemical compound [O-]S([O-])(=O)=O.CC1CCC[NH2+]C1.CC1CCC[NH2+]C1 OEZWWCFLLFPENR-UHFFFAOYSA-N 0.000 description 2
- BWGNESOTFCXPMA-UHFFFAOYSA-N Dihydrogen disulfide Chemical compound SS BWGNESOTFCXPMA-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- CVLWYOPXQNDTMC-UHFFFAOYSA-N acetic acid;4-methylpiperidine Chemical compound CC(O)=O.CC1CCNCC1 CVLWYOPXQNDTMC-UHFFFAOYSA-N 0.000 description 2
- IOJUPLGTWVMSFF-UHFFFAOYSA-N benzothiazole Chemical compound C1=CC=C2SC=NC2=C1 IOJUPLGTWVMSFF-UHFFFAOYSA-N 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- BSKHPKMHTQYZBB-UHFFFAOYSA-N 2-methylpyridine Chemical class CC1=CC=CC=N1 BSKHPKMHTQYZBB-UHFFFAOYSA-N 0.000 description 1
- DNHGDLPVASJBDU-UHFFFAOYSA-N 3-methylpiperidin-1-ium;phosphate Chemical compound [O-]P([O-])([O-])=O.CC1CCC[NH2+]C1.CC1CCC[NH2+]C1.CC1CCC[NH2+]C1 DNHGDLPVASJBDU-UHFFFAOYSA-N 0.000 description 1
- CNPURSDMOWDNOQ-UHFFFAOYSA-N 4-methoxy-7h-pyrrolo[2,3-d]pyrimidin-2-amine Chemical compound COC1=NC(N)=NC2=C1C=CN2 CNPURSDMOWDNOQ-UHFFFAOYSA-N 0.000 description 1
- GHRWHEKMYXUOGO-UHFFFAOYSA-N 4-methylpiperidin-1-ium;chloride Chemical compound Cl.CC1CCNCC1 GHRWHEKMYXUOGO-UHFFFAOYSA-N 0.000 description 1
- TXLZADJSYQUVIJ-UHFFFAOYSA-N 4-methylpiperidin-1-ium;sulfate Chemical compound [O-]S([O-])(=O)=O.CC1CC[NH2+]CC1.CC1CC[NH2+]CC1 TXLZADJSYQUVIJ-UHFFFAOYSA-N 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 1
- 239000005708 Sodium hypochlorite Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 239000012431 aqueous reaction media Substances 0.000 description 1
- 238000009903 catalytic hydrogenation reaction Methods 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 150000003841 chloride salts Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000006071 cream Substances 0.000 description 1
- 239000012045 crude solution Substances 0.000 description 1
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920003052 natural elastomer Polymers 0.000 description 1
- 229920001194 natural rubber Polymers 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 229940001593 sodium carbonate Drugs 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- SUKJFIGYRHOWBL-UHFFFAOYSA-N sodium hypochlorite Chemical group [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 1
- VLDHWMAJBNWALQ-UHFFFAOYSA-M sodium;1,3-benzothiazol-3-ide-2-thione Chemical compound [Na+].C1=CC=C2SC([S-])=NC2=C1 VLDHWMAJBNWALQ-UHFFFAOYSA-M 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 230000002311 subsequent effect Effects 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/36—Sulfur-, selenium-, or tellurium-containing compounds
- C08K5/45—Heterocyclic compounds having sulfur in the ring
- C08K5/46—Heterocyclic compounds having sulfur in the ring with oxygen or nitrogen in the ring
- C08K5/47—Thiazoles
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Plural Heterocyclic Compounds (AREA)
- Thiazole And Isothizaole Compounds (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
INVENTORS: Richard Leshin, Penelope R. Pappas and Dane K. Parker INVENTION: PREPARATION OF 2-(3-METHYLPIPERIDINOTHIO)-BENZOTHIAZOLE AND 2-(4-METHYLPIPERIDINOTHIO)-BENZOTHIAZOLE
Abstract of the Disclosure This invention relates to an improved procsss for preparing 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole wherein the order of addition of the reactants comprises slurrying benzothiazolyl disulfide in water, adding an oxidizing agent and effecting a reaction by the addition of an amine or an amine salt solution.
Abstract of the Disclosure This invention relates to an improved procsss for preparing 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole wherein the order of addition of the reactants comprises slurrying benzothiazolyl disulfide in water, adding an oxidizing agent and effecting a reaction by the addition of an amine or an amine salt solution.
Description
lO~S;~;~O
me present invention relates to 2-(3-methyl-piperidinothio)-benzothiazole and 2-(4-methylpiperidinothio) -benzothiazole and to a process for their preparation in water. More particularly this invention relates to the order of addition of the reactants when the reaction is carried out in water in the absence of organic solvents.
These sulfenamides are known to be good vulcani-zation accelerators for the curing of natural and synthetic rubber. mese materials do not exhibit early vulcanization, known as scorch, and accomplish vulcanization quickly once the vulcanization temperature has been reached.
Aqueous preparations of these sulfenamides have been reported in Canadian Patent No. 890,433 which discusses the merits of these compounds as accelerators and describes their preparation from sodium mercaptobenzothiazole in water, and from other benzothiazole-containing precursors in organic solvents. Preparation of these materials from benzothiazolyl disulfide in water is not described. Other examples of aqueous preparations of sulfenamides can be found in U.S. Patents 2~045,888; 3,178,428 and 3,144,652.
Attempts to prepare these materials using the usual prior art order of addition of oxidation of an aqueous benzothia-solyl disulfide-amine mixture, where the amine is 3-methyl-piperidine or 4-methylpiperidine~ yielded a product of poor form and poor purity.
It is therefore an ob~ect of the present invention to provide an improved process for the production of 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperi-dinothio)-benzothiazole in a completely aqueous medium.
Other ob~ects will become apparent to those skilled in this -1- .
10~i~3'~0 art as the description proceeds.
It has now unexpectedly been discovered that changing the order of addition of reactants according to the present invention allows preparation of 2-(3-methylpiperi-dinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole of good form, purity and yield. me sulfen-amides are prepared in an aqueous reaction medium by adding the amine to an aqueous benzothiazolyl disulfide and bleach mixture as contrasted to the prior art procedure of adding bleach to a mixture of amine and benzothiazolyl disulfide.
Ihe invention comprises (a) placing the benzothiazolyl disulfide in water to form a slurry, (b) adding bleach to the slurry, (c) adding an amine selected from the group consisting of 3-methylpiperidine and 4-methylpiperidine, and (d) allowing the mixture to react to obtain the sulfenamide.
me term "bleach" as used throughout the specifi-cation and claims is intended to denote oxidizing agentswhich permit the reaction to occur. The most preferred oxidizing agent is sodium hypochlorite, commonly referred to as bleach.
The invention as described uses a methylpiperidine pr~cursor. These methylpiperidines may be obtained by the catalytic reduction of the corresponding picolinium salts in aqueous acidic medium. Aqueous solutions of these methyl-piperidinium salts derived from such catalytic hydrogena-tions are adaptable for use in the present invention without neutralization, isolation or purification of the amine.
lU~;~3'~0 When utilizing these salts, the method of the present invention comprises (a) placing benzothiazolyl disulfide in water to form a slurry, (b) adding bleach to the slurry, (c) adding a suitable base such as aqueous sodium hydroxide, (d) adding a salt solution selected from the group consisting of sulfate, acetate and chloride salts of 3-methylpiperidine and 4-methylpiperidine,such as 4-methyl-piperidinium acetate and 3-methylpiperidinium sulfate, and (e) allowing the mixture to react.
The amine salts are thus neutralized in situ during the reaction. When desired, the amine salt solution can be preneutralized using a basic material to give a crude aqueous amine which can be used in the process in place of pure amine.
Representative examples of amine salts useful in the present invention are 3-methylpiperidinium sulfate, 4-methylpiperidinium acetate, 4-methylpiperidinium chloride and 3-methylpiperidinium phosphate.
Representative examples of suitable bases useful in the practice of the present invention are aqueous sodium hydroxide, aqueous potassium hydroxide, aqueous sodium car-bonate, aqueous potassium carbonate and aqueous sodium bi-carbonate.
The process of the present invention is effective when the bleach~ benzothiazolyl disulfide, an amine or amine salt and sodium hydroxide are present in stoichiometric amounts. Excess amounts of bleach from 0 to 45 percent and 10~53'~0 of amine from 0 to 35 percent can be used. While higher amounts of excess amine show slightly improved purity, the improvement is negligible at amine excesses above 45 percent.
Preferred proportions of reactants based on benzothiazolyl disulfide are from 25 to 35 percent molar excess of bleach and from 15 to 25 percent molar excess of amine or amine salt and sodium hydroxide. Such excesses of reactants pro-duce 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole of excellent purity and in higher yields than if stoichiometric amounts of reactants are used~
me process is generally carried out by adding bleach to an aqueous slurry of benzothiazolyl disulfide in a reaction chamber equipped with good agitation. me amine or amine salt and sodium hydroxide is then added at a moder-ate rate. me temperature is preferably maintained in a range of about 20 C. to about 45 C. during the addition, although temperatures from about 15 C. to about 90 C. can be used. The mixture is stirred briefly and cooled if necessaryO The product solidifies in the aqueous mixture when the aqueous mlxture is below the melting point of the solid. me product is then separated~ water washed and dried to complete the process.
me invention and its improvements over the art are more completely described with reference to the examples belcw in which all parts and percentages are by weight unless otherwise specified.
Example 1 shows the preparation of sulfenamide using the prior art bleach addition method. Example 2 demonstrates the process of the present invention. Example lO~S3'~0 3 illustrates the use of an amine salt solution in the process of the present invention. All examples used tech-nical grade (98.6%) benzothiazolyl disulfide.
,ExamPle 1 A 250 milliliter round-bottom flask was charged with 17.2 grams (.05 mole) of benzothiazolyl disulfide, 80 milliliters of water and 11.9 grams (.12 mole) of 3-methyl-piperidine. me mixture was stirred for 10 minutes at room temperature. A slimy, greenish emulsion resulted. To the emulsion was added 28.5 milliliters (.065 mole) of 2.28M
bleach dropwise over a 5 minute period. During the addition the temperature rose from 21 C. to 38.50 C. The emulsion was stirred for about 10 minutes between 380 C. and 34 C., during which time the product solidified in irregular greenish-brown chunks. After cooling to 240 C. the mixture was filtered. The product was water washed and dried at 40 C. me product was obtained in 97.3 percent yield and had a melting point between 55.50 c. and 590 c. Purity by reduction with hydrogen sulfide followed by titration of the amine with dilute acid was 90.2 percent.
ExamPle 2 A 250 milliliter round-bottom flask was charged with 17.2 grams (.05 mole) of benzothiazolyl disulfide, 80 milliliters of water~ and 28.5 milliliters (.065 mole) of
me present invention relates to 2-(3-methyl-piperidinothio)-benzothiazole and 2-(4-methylpiperidinothio) -benzothiazole and to a process for their preparation in water. More particularly this invention relates to the order of addition of the reactants when the reaction is carried out in water in the absence of organic solvents.
These sulfenamides are known to be good vulcani-zation accelerators for the curing of natural and synthetic rubber. mese materials do not exhibit early vulcanization, known as scorch, and accomplish vulcanization quickly once the vulcanization temperature has been reached.
Aqueous preparations of these sulfenamides have been reported in Canadian Patent No. 890,433 which discusses the merits of these compounds as accelerators and describes their preparation from sodium mercaptobenzothiazole in water, and from other benzothiazole-containing precursors in organic solvents. Preparation of these materials from benzothiazolyl disulfide in water is not described. Other examples of aqueous preparations of sulfenamides can be found in U.S. Patents 2~045,888; 3,178,428 and 3,144,652.
Attempts to prepare these materials using the usual prior art order of addition of oxidation of an aqueous benzothia-solyl disulfide-amine mixture, where the amine is 3-methyl-piperidine or 4-methylpiperidine~ yielded a product of poor form and poor purity.
It is therefore an ob~ect of the present invention to provide an improved process for the production of 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperi-dinothio)-benzothiazole in a completely aqueous medium.
Other ob~ects will become apparent to those skilled in this -1- .
10~i~3'~0 art as the description proceeds.
It has now unexpectedly been discovered that changing the order of addition of reactants according to the present invention allows preparation of 2-(3-methylpiperi-dinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole of good form, purity and yield. me sulfen-amides are prepared in an aqueous reaction medium by adding the amine to an aqueous benzothiazolyl disulfide and bleach mixture as contrasted to the prior art procedure of adding bleach to a mixture of amine and benzothiazolyl disulfide.
Ihe invention comprises (a) placing the benzothiazolyl disulfide in water to form a slurry, (b) adding bleach to the slurry, (c) adding an amine selected from the group consisting of 3-methylpiperidine and 4-methylpiperidine, and (d) allowing the mixture to react to obtain the sulfenamide.
me term "bleach" as used throughout the specifi-cation and claims is intended to denote oxidizing agentswhich permit the reaction to occur. The most preferred oxidizing agent is sodium hypochlorite, commonly referred to as bleach.
The invention as described uses a methylpiperidine pr~cursor. These methylpiperidines may be obtained by the catalytic reduction of the corresponding picolinium salts in aqueous acidic medium. Aqueous solutions of these methyl-piperidinium salts derived from such catalytic hydrogena-tions are adaptable for use in the present invention without neutralization, isolation or purification of the amine.
lU~;~3'~0 When utilizing these salts, the method of the present invention comprises (a) placing benzothiazolyl disulfide in water to form a slurry, (b) adding bleach to the slurry, (c) adding a suitable base such as aqueous sodium hydroxide, (d) adding a salt solution selected from the group consisting of sulfate, acetate and chloride salts of 3-methylpiperidine and 4-methylpiperidine,such as 4-methyl-piperidinium acetate and 3-methylpiperidinium sulfate, and (e) allowing the mixture to react.
The amine salts are thus neutralized in situ during the reaction. When desired, the amine salt solution can be preneutralized using a basic material to give a crude aqueous amine which can be used in the process in place of pure amine.
Representative examples of amine salts useful in the present invention are 3-methylpiperidinium sulfate, 4-methylpiperidinium acetate, 4-methylpiperidinium chloride and 3-methylpiperidinium phosphate.
Representative examples of suitable bases useful in the practice of the present invention are aqueous sodium hydroxide, aqueous potassium hydroxide, aqueous sodium car-bonate, aqueous potassium carbonate and aqueous sodium bi-carbonate.
The process of the present invention is effective when the bleach~ benzothiazolyl disulfide, an amine or amine salt and sodium hydroxide are present in stoichiometric amounts. Excess amounts of bleach from 0 to 45 percent and 10~53'~0 of amine from 0 to 35 percent can be used. While higher amounts of excess amine show slightly improved purity, the improvement is negligible at amine excesses above 45 percent.
Preferred proportions of reactants based on benzothiazolyl disulfide are from 25 to 35 percent molar excess of bleach and from 15 to 25 percent molar excess of amine or amine salt and sodium hydroxide. Such excesses of reactants pro-duce 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole of excellent purity and in higher yields than if stoichiometric amounts of reactants are used~
me process is generally carried out by adding bleach to an aqueous slurry of benzothiazolyl disulfide in a reaction chamber equipped with good agitation. me amine or amine salt and sodium hydroxide is then added at a moder-ate rate. me temperature is preferably maintained in a range of about 20 C. to about 45 C. during the addition, although temperatures from about 15 C. to about 90 C. can be used. The mixture is stirred briefly and cooled if necessaryO The product solidifies in the aqueous mixture when the aqueous mlxture is below the melting point of the solid. me product is then separated~ water washed and dried to complete the process.
me invention and its improvements over the art are more completely described with reference to the examples belcw in which all parts and percentages are by weight unless otherwise specified.
Example 1 shows the preparation of sulfenamide using the prior art bleach addition method. Example 2 demonstrates the process of the present invention. Example lO~S3'~0 3 illustrates the use of an amine salt solution in the process of the present invention. All examples used tech-nical grade (98.6%) benzothiazolyl disulfide.
,ExamPle 1 A 250 milliliter round-bottom flask was charged with 17.2 grams (.05 mole) of benzothiazolyl disulfide, 80 milliliters of water and 11.9 grams (.12 mole) of 3-methyl-piperidine. me mixture was stirred for 10 minutes at room temperature. A slimy, greenish emulsion resulted. To the emulsion was added 28.5 milliliters (.065 mole) of 2.28M
bleach dropwise over a 5 minute period. During the addition the temperature rose from 21 C. to 38.50 C. The emulsion was stirred for about 10 minutes between 380 C. and 34 C., during which time the product solidified in irregular greenish-brown chunks. After cooling to 240 C. the mixture was filtered. The product was water washed and dried at 40 C. me product was obtained in 97.3 percent yield and had a melting point between 55.50 c. and 590 c. Purity by reduction with hydrogen sulfide followed by titration of the amine with dilute acid was 90.2 percent.
ExamPle 2 A 250 milliliter round-bottom flask was charged with 17.2 grams (.05 mole) of benzothiazolyl disulfide, 80 milliliters of water~ and 28.5 milliliters (.065 mole) of
2.28M bleach. The mixture was stirred, forming a cream colored slurry after approximately 10 minutes. To this slurry was added 11.9 grams (.12 mole) 3-methylpiperidine dropwise over a 5 minute period. During the addition the temperature rose to 35 C. The emulsion was allowed to stir for about 10 minutes at a temperature between 380 C. and 10~53'~0 35 C. The mixture was cooled to 240 C. solidifying the product as small, light tan granules of uniform size. The solids were filtered, washed with water and dried at ~oo C.
The product was obtained in 98.4 percent yield, having a melting point between 57.5O C. and 61 C. A purity of 96.9 percent was obtained using the method described in Example 1.
Exam~le ~
A 250 milliliter round-bottom flask was charged with 8.6 grams (.025 mole) of benzothiazolyl disulfide, 40 milliliters of water and 13.6 milliliters (.0325 mole) of 2.39M bleach. A solution of 2.4 grams (.o6 mole) of sodium hydroxide in 10 milliliters of water was added. me mixture was cooled slightly to maintain the temperature at about 250 C. To this mixture was added 20.4 grams (.06 mole) of an aqueous solution of 4-methylpiperidinium sulfate (29.2 percent theoretical amine content) dropwise over a 2 minute period while the mixture was agitating. ~uring addition the temperature rose from 21 C. to 29.50 C. me mixture was stirred for approximately 15 minutes at 280 C. to 29 C.
during which time the product solidified as tan granules.
The granules were water washed and dried at 40 C. me product was obtained in 96.6 percent yield and had a melting point between 48.5 and 50 C. Using the method described in Example 1~ a purity of 94.5 percent was obtained.
me results of Examples 1-3 are s D arized in Table I. me column titled "Method of Addition" refers to the material added last to a mixture of benzothiazolyl di-sulfide and other reactants. Thus~ Example 1 is seen to be an illustration of prior art procedures and Examples 2 and
The product was obtained in 98.4 percent yield, having a melting point between 57.5O C. and 61 C. A purity of 96.9 percent was obtained using the method described in Example 1.
Exam~le ~
A 250 milliliter round-bottom flask was charged with 8.6 grams (.025 mole) of benzothiazolyl disulfide, 40 milliliters of water and 13.6 milliliters (.0325 mole) of 2.39M bleach. A solution of 2.4 grams (.o6 mole) of sodium hydroxide in 10 milliliters of water was added. me mixture was cooled slightly to maintain the temperature at about 250 C. To this mixture was added 20.4 grams (.06 mole) of an aqueous solution of 4-methylpiperidinium sulfate (29.2 percent theoretical amine content) dropwise over a 2 minute period while the mixture was agitating. ~uring addition the temperature rose from 21 C. to 29.50 C. me mixture was stirred for approximately 15 minutes at 280 C. to 29 C.
during which time the product solidified as tan granules.
The granules were water washed and dried at 40 C. me product was obtained in 96.6 percent yield and had a melting point between 48.5 and 50 C. Using the method described in Example 1~ a purity of 94.5 percent was obtained.
me results of Examples 1-3 are s D arized in Table I. me column titled "Method of Addition" refers to the material added last to a mixture of benzothiazolyl di-sulfide and other reactants. Thus~ Example 1 is seen to be an illustration of prior art procedures and Examples 2 and
3 are illustrations of the present invention.
iO~;53'~0 Table I
Method of Amine Yield Melting Purity Ex. Addition Source (%) Point C. (%) Form 1 bleach amine 97.3 55-59 90.2greenish chunks 2 amine amine 98.4 57.5-61 96.9 tan granules 3 amine salt amine salt 96.6 48.5-50 94.5 tan granules Examples 1 and 2 demonstrate the contrast between the prior art and the methods of the present invention.
When the process of the prior art is used in aqueous solu-tion, a preliminary reaction between the disulfide and amine occurs in the water giving a curd-like mixture thought to be sulfenamide and amine-mercaptobenzothiazole salts. Subse-quent bleach oxidation of this mixture as described in Example 1 results in a sulfenamide of lower purity and poor form. me process of the present invention avoids the pre-reaction. A clean oxidation to the sulfenamide results when the amine is added to the disulfide in the presence of aqueous bleach as described and exemplified in Example 2.
The amine salt solution addition described in Example 3 may also be run using preneutralized amine salt solution. me preneutralization gives a crude solution of aqueous amine which can then be used in the process exem-plified in Example 2 in place of pure amine. The reaction is now the same as the process using pure amine, except water is present in the reagent amine.
While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art 10~i53'~0 that various changes and modifications may be made therein without departing from the spirit or scope of the invention.
iO~;53'~0 Table I
Method of Amine Yield Melting Purity Ex. Addition Source (%) Point C. (%) Form 1 bleach amine 97.3 55-59 90.2greenish chunks 2 amine amine 98.4 57.5-61 96.9 tan granules 3 amine salt amine salt 96.6 48.5-50 94.5 tan granules Examples 1 and 2 demonstrate the contrast between the prior art and the methods of the present invention.
When the process of the prior art is used in aqueous solu-tion, a preliminary reaction between the disulfide and amine occurs in the water giving a curd-like mixture thought to be sulfenamide and amine-mercaptobenzothiazole salts. Subse-quent bleach oxidation of this mixture as described in Example 1 results in a sulfenamide of lower purity and poor form. me process of the present invention avoids the pre-reaction. A clean oxidation to the sulfenamide results when the amine is added to the disulfide in the presence of aqueous bleach as described and exemplified in Example 2.
The amine salt solution addition described in Example 3 may also be run using preneutralized amine salt solution. me preneutralization gives a crude solution of aqueous amine which can then be used in the process exem-plified in Example 2 in place of pure amine. The reaction is now the same as the process using pure amine, except water is present in the reagent amine.
While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art 10~i53'~0 that various changes and modifications may be made therein without departing from the spirit or scope of the invention.
Claims (7)
1. An improved process for the preparation of a sulfenamide selected from the group consisting of 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperi-dinothio)-benzothiazole by reacting an amine selected from the group consisting of 3-methylpiperidine and 4-methyl-piperidine with benzothiazolyl disulfide in the presence of bleach, the improvement comprising (a) placing benzothiazolyl disulfide in water to form a slurry, (b) adding bleach to the slurry, (c) adding an amine selected from the group con-sisting of 3-methylpiperidine and 4-methylpiperidine, and (d) allowing the mixture to react.
2. A process as described in claim 1 wherein the bleach is present in a concentration of from 0 to 45 percent in excess of a stoichiometric amount of benzothiazolyl di-sulfide and the amine is present in a concentration of from 0 to 35 percent in excess of a stoichiometric amount of benzothiazolyl disulfide.
3. A process as described in claim 1 wherein the reaction takes place by adding the amine to a mixture of benzothiazolyl disulfide in bleach at a temperature of from 20° C. to 45° C. during agitation, separating the product and water washing the product before drying.
4. A process as described in claim 1 wherein the amine is 3-methylpiperidine and the sulfenamide is 2-(3-methylpiperidinothio)-benzothiazole.
5. A process as described in claim 1 wherein the amine is 4-methylpiperidine and the sulfenamide is 2-(4-methylpiperidinothio)-benzothiazole.
6. A process for preparing a sulfenamide selected from the group consisting of 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole comprising (a) placing benzothiazolyl disulfide in water to form a slurry, (b) adding bleach to the slurry, (c) adding an aqueous base selected from the group consisting of sodium hydroxide and potassium hydroxide to the slurry, (d) adding a salt solution selected from the group consisting of sulfate, acetate, chloride and phosphate salts of 3-methylpiperidine and 4-methylpiperidine, and (e) allowing the mixture to react.
7. A process as described in Claim 1 wherein the amine in step (c) is formed in situ in the mixture resulting from steps (a) and (b) by the addition to said mixture of an amine salt selected from the group consisting of the sulfate, acetate, chloride and phosphate salts of 3-methylpiperidine and 4-methylpiperidine and an aqueous base selected from the group consisting of sodium hydroxide and potassium hydroxide.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US51280674A | 1974-10-04 | 1974-10-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1065320A true CA1065320A (en) | 1979-10-30 |
Family
ID=24040650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA233,629A Expired CA1065320A (en) | 1974-10-04 | 1975-08-18 | Preparation of 2-(3-methylpiperidinothio)-benzothiazole and 2-(4-methylpiperidinothio)-benzothiazole |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5159871A (en) |
| BE (1) | BE833693A (en) |
| BR (1) | BR7506358A (en) |
| CA (1) | CA1065320A (en) |
| DE (1) | DE2537755A1 (en) |
| FR (1) | FR2286828A1 (en) |
| GB (1) | GB1464338A (en) |
| NL (1) | NL7511675A (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1050998B (en) * | 1954-07-27 | 1959-02-19 | United States Rubber Company, New York, N. Y. (V. St. A.) | Vulcanization process for rubber |
| GB1289654A (en) * | 1970-01-30 | 1972-09-20 |
-
1975
- 1975-05-14 GB GB2036475A patent/GB1464338A/en not_active Expired
- 1975-08-18 CA CA233,629A patent/CA1065320A/en not_active Expired
- 1975-08-25 DE DE19752537755 patent/DE2537755A1/en active Pending
- 1975-09-18 FR FR7528592A patent/FR2286828A1/en active Granted
- 1975-09-22 BE BE160270A patent/BE833693A/en unknown
- 1975-09-30 JP JP50118202A patent/JPS5159871A/en active Pending
- 1975-10-01 BR BR7506358*A patent/BR7506358A/en unknown
- 1975-10-03 NL NL7511675A patent/NL7511675A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| BR7506358A (en) | 1976-08-17 |
| BE833693A (en) | 1976-01-16 |
| JPS5159871A (en) | 1976-05-25 |
| FR2286828B1 (en) | 1979-03-16 |
| NL7511675A (en) | 1976-04-06 |
| GB1464338A (en) | 1977-02-09 |
| DE2537755A1 (en) | 1976-04-15 |
| FR2286828A1 (en) | 1976-04-30 |
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