CA1129860A - Process for the preparation of benzothiazolyl sulphenic acid morpholide - Google Patents
Process for the preparation of benzothiazolyl sulphenic acid morpholideInfo
- Publication number
- CA1129860A CA1129860A CA325,292A CA325292A CA1129860A CA 1129860 A CA1129860 A CA 1129860A CA 325292 A CA325292 A CA 325292A CA 1129860 A CA1129860 A CA 1129860A
- Authority
- CA
- Canada
- Prior art keywords
- benzothiazolyl
- mbs
- sulphenic acid
- preparation
- morpholide
- 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
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
- C07D277/80—Sulfur atoms attached to a second hetero atom to a nitrogen atom
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)
- Plural Heterocyclic Compounds (AREA)
- Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Thiazole And Isothizaole Compounds (AREA)
Abstract
PROCESS FOR THE PREPARATION OF BENZOTHIAZOLYL
SULPHENIC ACID MORPHOLIDE
Abstract of the Disclosure A process for the preparation of 2-benzothiazolyl sulphenic acid morpholide in an aqueous medium wherein the reaction product is separated in the molten state by heating the suspension with melting of the solid reaction product, subsequent rapid separation of the melt phase from the aqueous phase, and removal of volatile constituents still present in the melt phase, the sum of residence times amount-ing to not more than 15 minutes.
Le A 18 561
SULPHENIC ACID MORPHOLIDE
Abstract of the Disclosure A process for the preparation of 2-benzothiazolyl sulphenic acid morpholide in an aqueous medium wherein the reaction product is separated in the molten state by heating the suspension with melting of the solid reaction product, subsequent rapid separation of the melt phase from the aqueous phase, and removal of volatile constituents still present in the melt phase, the sum of residence times amount-ing to not more than 15 minutes.
Le A 18 561
Description
9~6c~
This invention relates to a process for the preparation of 2-benzothiazolyl sulphenic acid morpholide (hereinafter referred to ~s MBS) in which the MBS is separated in the solvent-free state from an aqueous reaction mixture and obtained in a high degree of purity and stability in storage.
The aqueous reaction mixture i9 obtained when MBS
is synthesized from 2-benzothiazolyl di~ulphide, mercaptobenzothiazole or its sodium salt and a multiple molar excess of morpholine by the action of an oxidizing agent such as NaOCl, C12 or ~ 2 The term "MBS" is used in this invention to denote not only 2-benzothi~zolyl sulphenic acid morpholide but also the corresponding compounds which are alkyl-substituted in the morpholine moiety, such as the product obtained from the re~ction with 2,6-dimethylmorpholine. MBS is an important vulcanization accelerator from the class o~ sulphenamides.
It is known that the synthesis of benzothiazolyl sulphenamides can be carried out in an organic solvent.
The desired end product is obtained as a solution in the organic solvent and is either precipitated by the addition of water or obtained as a solvent-free melt by evaporation of the solvent (US Patent No. 2,782,202).
It is also known (US Patent No. 3,178,~28) that MBS can be prepared in an aqueous mixture in which the sulphenamide is insoluble. A sufficiently high tem-perature may be employed in this method so that the MBS
can be directly obtained in the molten state. In that case, however, the molar quantity of morpholine used 3o must not exceed 1.5 times the molar quantity of benzo-thiazole derivatives present, so as to ensure that the MBS will not decompose prematurely, i.e. while the reaction is taking place. Since morpholine is used in such a small e~cess of only 50 mol /0, a reaction time of several hours is required.
Le A 18 561 , ~
If a short reaction time is required~ it i9 generally necessary to carry out the reaction in an aqueous mixture with a molar excess o~ morpholine of 200% or more. In order to prevent decomposition of MBS during its preparation when such a large excess of morpholine i9 used, the reaction temperature must be kept well below the melting point of MBS (about 82 to 85C). The reaction i9 therefore generally carried out in the range of from 30 to 60C.
It is well known that there are considerable disadvantages in converting MBS, which has been obtained from a reaction mixture with a large excess of morpholine, into the solvent-free liquid state and keeping it in such state, sirlce MBS is a relatively unstable substance which rapidly decomposes at elevated temper-atures. It is also known that sulphenamides decompose all the more rapidly the higher the concentration of ~ree amine.
Aqueous reaction mixtures obtained ~rom the prepa-ration of MBS using a large molar excess of morpholinehave therefore hitherto o~ necessity been worked up as suspensio~s at room temperature, for example by filtering the crystalline insoluble MBS from the reaction mixture, freeing it from mother liquor by vigorous washing with large quantities of water, and then drying. These operations, however, as also the recovery of morpholine from the wash waters~ are time consuming and expensive.
The preparation of MBS with a large excess of morpholine results in a suspension of solid MBS in a 3o mixture of water and morpholine which still contains, in solution7 organic by-products and sometimes also inorganic salts formed in the reaction. Such a suspension contains more than 0.5 mol of morpholine, generally from 1.5 to
This invention relates to a process for the preparation of 2-benzothiazolyl sulphenic acid morpholide (hereinafter referred to ~s MBS) in which the MBS is separated in the solvent-free state from an aqueous reaction mixture and obtained in a high degree of purity and stability in storage.
The aqueous reaction mixture i9 obtained when MBS
is synthesized from 2-benzothiazolyl di~ulphide, mercaptobenzothiazole or its sodium salt and a multiple molar excess of morpholine by the action of an oxidizing agent such as NaOCl, C12 or ~ 2 The term "MBS" is used in this invention to denote not only 2-benzothi~zolyl sulphenic acid morpholide but also the corresponding compounds which are alkyl-substituted in the morpholine moiety, such as the product obtained from the re~ction with 2,6-dimethylmorpholine. MBS is an important vulcanization accelerator from the class o~ sulphenamides.
It is known that the synthesis of benzothiazolyl sulphenamides can be carried out in an organic solvent.
The desired end product is obtained as a solution in the organic solvent and is either precipitated by the addition of water or obtained as a solvent-free melt by evaporation of the solvent (US Patent No. 2,782,202).
It is also known (US Patent No. 3,178,~28) that MBS can be prepared in an aqueous mixture in which the sulphenamide is insoluble. A sufficiently high tem-perature may be employed in this method so that the MBS
can be directly obtained in the molten state. In that case, however, the molar quantity of morpholine used 3o must not exceed 1.5 times the molar quantity of benzo-thiazole derivatives present, so as to ensure that the MBS will not decompose prematurely, i.e. while the reaction is taking place. Since morpholine is used in such a small e~cess of only 50 mol /0, a reaction time of several hours is required.
Le A 18 561 , ~
If a short reaction time is required~ it i9 generally necessary to carry out the reaction in an aqueous mixture with a molar excess o~ morpholine of 200% or more. In order to prevent decomposition of MBS during its preparation when such a large excess of morpholine i9 used, the reaction temperature must be kept well below the melting point of MBS (about 82 to 85C). The reaction i9 therefore generally carried out in the range of from 30 to 60C.
It is well known that there are considerable disadvantages in converting MBS, which has been obtained from a reaction mixture with a large excess of morpholine, into the solvent-free liquid state and keeping it in such state, sirlce MBS is a relatively unstable substance which rapidly decomposes at elevated temper-atures. It is also known that sulphenamides decompose all the more rapidly the higher the concentration of ~ree amine.
Aqueous reaction mixtures obtained ~rom the prepa-ration of MBS using a large molar excess of morpholinehave therefore hitherto o~ necessity been worked up as suspensio~s at room temperature, for example by filtering the crystalline insoluble MBS from the reaction mixture, freeing it from mother liquor by vigorous washing with large quantities of water, and then drying. These operations, however, as also the recovery of morpholine from the wash waters~ are time consuming and expensive.
The preparation of MBS with a large excess of morpholine results in a suspension of solid MBS in a 3o mixture of water and morpholine which still contains, in solution7 organic by-products and sometimes also inorganic salts formed in the reaction. Such a suspension contains more than 0.5 mol of morpholine, generally from 1.5 to
2 mols per mol of MBS.
It has now been ~ound that MBS can be obtained in the Le A 18 561 form of a solvent-free liquid of high quality and stability from a suspension if the suspension is heated to melt the crystalline MBS, the resulting molten phase is rapidly separated from the aqueous phase, and the molten phase is then freed from any volatile constituellts still presen-t, such as wa~e~ and morphol~ne.
These operations are carried out in immediate succession o~er a total period of not more than 15 minutes.
This invention thus provides a process for isolating a 2-benzothiazolyl sulphenic acid morpholide from an aqueous suspension thereof, which comprises ta) heating the suspension to melt the morpholide, (b) rapidly separating the molten phase from the aqueous phase, and (c) removing volatile constituents still present in the molten phase, the sum of residence times from beginning to end of the three stages (a) to (c) amounting to not more than 15 minutes.
It is suprisingly found that in spite of the large excess of morpholine originally present, thi~ method results in an MBS
melt which is stable in storage and does not undergo the rapid decomposition normally found in MBS.
The process according to the in~ention is equally applicable to the preparation and separation of the various analogues, in particular 2-benzothiazolyl sulphenic acid 2,6-dimethylmorpholide.
The various stages of the process according to the ..J ~
invention may be carried out by known methods. For example, heating of the suspension and its conversion into a mixture o~ aqueous phase and melt phase may be - carried out by direct supply of energy or indirectly, 8 . g. in a heat exchanger. The subsequent isolation Or the melt phase may be achleved by the action Or centri-fugal force, e.g. in a ~eparator, or by gravity~ e.g.
in a ~eparating flask. Subsequent freeing of the melt phase from volatile constituents, such as water and morpholine, is ad~antageously carried out by rapid evaporation, preferably under vacuumJ e.g. in a thin layer evaporator.
When carrying out the stage of evaporation of the melt phase, it has been found to be an additional advantage to carry a stream of gas, e.g. nitrogen, air and/or steam, in countercurrent to the film of mel-k.
The procedure described above obviates the time-consuming stages of f:iltration7 washing and drying of the MBS produced in suspension in the presence of a large excess of morpholine as well as the costl7 procedure of recovering the morpholine from the wash waters.
The melt of MBS which is obtained after stage (c) may be converted into the solid crystalline state 25 by cooling in known manner so that the MBS may be obtained in a usual commercial form.
The invention is illustrated in the following Examples. The percentages given are percentages by weight.
30 Example 1 150 kg of a reaction mixture obtained from the synthesis of MBS and consisting of 20% Of MBS~ 20%
of morpholine, 10h of sodium chloride, 49/0 of water, and lh of by-product and having ~ temp~rature o~ about 30C
35 are pumped through a steam-heated tubular heat exchanger.
Le A 18 561 ;Z9~6 The re~idence time during heating up is 1.6 minutes.
The mixture, which i 3 obtained from the heat exchanger at u temperature of about B5C, i8 fed into the iront end of a separating flask which i9 inclined at an angle of 3. While the aqueous phase flows lnto a reaeiver ~rom the highest point at the rear end of the ~eparating flask, the dropY of melt sink to the bottom and flow a~
a layer to the lowest point in the flask, from where they are continuously removed through a discharge valve so that a residence time of 4 minutes is not exceeded~
A short inclined piece of pipe is attached to the bottom discharge valve of the separating flask and opens into the inlet of a commercial thin layer evaporator having a heating surface o~ 0.2 m2. The evaporator is operated at 30 Torr and 120C. Steam is injected at its lower end at the same temperature at the rate of about 2 kg/hour. The residence time in the thin layer evaporato~r is less than 1 minute. A melt of MBS, which 20 has excellent stability in storage and in which the residual morpholine content is about 0.2~o by weight, is removed from the sump of the thin layer evaporator at the rate of about 30 kg/hour. The melt can be converted into the usual commercial form of scales by cooling on a scraping roller.
Example 2 A reaction mixture obtained from the synthesis of MBS and consisting Of 21.7% of MBS, 21.7% of morpholine, 1.1~ of organic by-products and 55.5% of water is passed through a heat-insulated tube at the rate of 138 kg/hour.
Steam is added to the reaction mixture at the rate of 12 kg/hour just behind the tube inlet. The mixture leaves the tube at about 85C; its residence time in the tube is about 10 seconds. It then flows into a centri-fugal separator 1 litre in capacity, where it is separated Le A 18 561 ,, ~ , :
- ' ~
' 8~
into a melt phase and an aqueous phase. The residence time of the melt in the separator is less than 60 seconds. The melt flows through a 0.5 litre storage vessel to a thin layer evaporator which has a heatlng surface of 0.2 m2 and which is operated at 120C ~nd 30 Torr, Nitrogen at the same temperature is in,jected into the lower end of the evaporator at a rate of about ?.5 Nm3/h. An MBS melt which contains a residue of about 0.2% by weight of morpholine and i9 very stable in storage is discharged from the sump of the thin layer evaporator at about 30 kg/hour.
E~ample 3 138 kg/hour of a reaction mixture consisting of 20% by weight of 2-benzothiazolyl sulphe~ic acid 2,S-dimethylmorpholide, 20% of 2~ 6-dimethylmorpholine, 7.5% of sodium chloride, 51% of water and 1.5% Of by-products are treated in the same way as described in Example 2 . 27 . 5 kg of a melt of 2-benzothiazolyl sulphenic acid 2,6-dimethylmorpholide which has very good stability in storage are obtained. This product can be converted into a commercial form by cooling on a scraping roller.
Le A 18 561
It has now been ~ound that MBS can be obtained in the Le A 18 561 form of a solvent-free liquid of high quality and stability from a suspension if the suspension is heated to melt the crystalline MBS, the resulting molten phase is rapidly separated from the aqueous phase, and the molten phase is then freed from any volatile constituellts still presen-t, such as wa~e~ and morphol~ne.
These operations are carried out in immediate succession o~er a total period of not more than 15 minutes.
This invention thus provides a process for isolating a 2-benzothiazolyl sulphenic acid morpholide from an aqueous suspension thereof, which comprises ta) heating the suspension to melt the morpholide, (b) rapidly separating the molten phase from the aqueous phase, and (c) removing volatile constituents still present in the molten phase, the sum of residence times from beginning to end of the three stages (a) to (c) amounting to not more than 15 minutes.
It is suprisingly found that in spite of the large excess of morpholine originally present, thi~ method results in an MBS
melt which is stable in storage and does not undergo the rapid decomposition normally found in MBS.
The process according to the in~ention is equally applicable to the preparation and separation of the various analogues, in particular 2-benzothiazolyl sulphenic acid 2,6-dimethylmorpholide.
The various stages of the process according to the ..J ~
invention may be carried out by known methods. For example, heating of the suspension and its conversion into a mixture o~ aqueous phase and melt phase may be - carried out by direct supply of energy or indirectly, 8 . g. in a heat exchanger. The subsequent isolation Or the melt phase may be achleved by the action Or centri-fugal force, e.g. in a ~eparator, or by gravity~ e.g.
in a ~eparating flask. Subsequent freeing of the melt phase from volatile constituents, such as water and morpholine, is ad~antageously carried out by rapid evaporation, preferably under vacuumJ e.g. in a thin layer evaporator.
When carrying out the stage of evaporation of the melt phase, it has been found to be an additional advantage to carry a stream of gas, e.g. nitrogen, air and/or steam, in countercurrent to the film of mel-k.
The procedure described above obviates the time-consuming stages of f:iltration7 washing and drying of the MBS produced in suspension in the presence of a large excess of morpholine as well as the costl7 procedure of recovering the morpholine from the wash waters.
The melt of MBS which is obtained after stage (c) may be converted into the solid crystalline state 25 by cooling in known manner so that the MBS may be obtained in a usual commercial form.
The invention is illustrated in the following Examples. The percentages given are percentages by weight.
30 Example 1 150 kg of a reaction mixture obtained from the synthesis of MBS and consisting of 20% Of MBS~ 20%
of morpholine, 10h of sodium chloride, 49/0 of water, and lh of by-product and having ~ temp~rature o~ about 30C
35 are pumped through a steam-heated tubular heat exchanger.
Le A 18 561 ;Z9~6 The re~idence time during heating up is 1.6 minutes.
The mixture, which i 3 obtained from the heat exchanger at u temperature of about B5C, i8 fed into the iront end of a separating flask which i9 inclined at an angle of 3. While the aqueous phase flows lnto a reaeiver ~rom the highest point at the rear end of the ~eparating flask, the dropY of melt sink to the bottom and flow a~
a layer to the lowest point in the flask, from where they are continuously removed through a discharge valve so that a residence time of 4 minutes is not exceeded~
A short inclined piece of pipe is attached to the bottom discharge valve of the separating flask and opens into the inlet of a commercial thin layer evaporator having a heating surface o~ 0.2 m2. The evaporator is operated at 30 Torr and 120C. Steam is injected at its lower end at the same temperature at the rate of about 2 kg/hour. The residence time in the thin layer evaporato~r is less than 1 minute. A melt of MBS, which 20 has excellent stability in storage and in which the residual morpholine content is about 0.2~o by weight, is removed from the sump of the thin layer evaporator at the rate of about 30 kg/hour. The melt can be converted into the usual commercial form of scales by cooling on a scraping roller.
Example 2 A reaction mixture obtained from the synthesis of MBS and consisting Of 21.7% of MBS, 21.7% of morpholine, 1.1~ of organic by-products and 55.5% of water is passed through a heat-insulated tube at the rate of 138 kg/hour.
Steam is added to the reaction mixture at the rate of 12 kg/hour just behind the tube inlet. The mixture leaves the tube at about 85C; its residence time in the tube is about 10 seconds. It then flows into a centri-fugal separator 1 litre in capacity, where it is separated Le A 18 561 ,, ~ , :
- ' ~
' 8~
into a melt phase and an aqueous phase. The residence time of the melt in the separator is less than 60 seconds. The melt flows through a 0.5 litre storage vessel to a thin layer evaporator which has a heatlng surface of 0.2 m2 and which is operated at 120C ~nd 30 Torr, Nitrogen at the same temperature is in,jected into the lower end of the evaporator at a rate of about ?.5 Nm3/h. An MBS melt which contains a residue of about 0.2% by weight of morpholine and i9 very stable in storage is discharged from the sump of the thin layer evaporator at about 30 kg/hour.
E~ample 3 138 kg/hour of a reaction mixture consisting of 20% by weight of 2-benzothiazolyl sulphe~ic acid 2,S-dimethylmorpholide, 20% of 2~ 6-dimethylmorpholine, 7.5% of sodium chloride, 51% of water and 1.5% Of by-products are treated in the same way as described in Example 2 . 27 . 5 kg of a melt of 2-benzothiazolyl sulphenic acid 2,6-dimethylmorpholide which has very good stability in storage are obtained. This product can be converted into a commercial form by cooling on a scraping roller.
Le A 18 561
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for isolating a 2-benzothiazolyl sulphenic acid morpholide from an aqueous suspension thereof, which comprises (a) heating the suspension to melt the morpholide, (b) rapidly separating the molten phase from the aqueous phase, and (c) removing volatile constituents still present in the molten phase, the sum of residence times from beginning to end of the three stages (a) to (c) amounting to not more than 15 minutes.
2. A process according to claim 1 wherein the 2-benzothiazolyl sulphenic acid morpholide is 2-benzothiazolyl sulphenic acid morpholide.
3. A process according to claim 1 wherein the 2-benzothiazolyl sulphenic acid morpholide is 2-benzothiazolyl sulphenic acid 2,5-morpholide.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19782815964 DE2815964A1 (en) | 1978-04-13 | 1978-04-13 | METHOD FOR PRODUCING BENZTHIAZOLYL SULFEN ACID MORPHOLIDE |
| DEP2815964.0 | 1978-04-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1129860A true CA1129860A (en) | 1982-08-17 |
Family
ID=6036857
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA325,292A Expired CA1129860A (en) | 1978-04-13 | 1979-04-11 | Process for the preparation of benzothiazolyl sulphenic acid morpholide |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0004896B1 (en) |
| JP (1) | JPS54135781A (en) |
| AU (1) | AU517673B2 (en) |
| BR (1) | BR7902255A (en) |
| CA (1) | CA1129860A (en) |
| DE (2) | DE2815964A1 (en) |
| ES (1) | ES479471A1 (en) |
| ZA (1) | ZA791766B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3325724A1 (en) * | 1983-07-16 | 1985-01-24 | Akzo Gmbh, 5600 Wuppertal | METHOD FOR PRODUCING THIAZOLYL-2 SULFENAMIDES |
| DE3430435A1 (en) * | 1984-08-18 | 1986-02-27 | Bayer Ag, 5090 Leverkusen | METHOD FOR PRODUCING BENZOTHIAZOLYL SULFEN AMIDES |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2271834A (en) * | 1939-03-03 | 1942-02-03 | Firestone Tire & Rubber Co | Method of treating mercaptothiazoles with ammonia derivatives |
| US2782202A (en) * | 1955-09-27 | 1957-02-19 | Goodyear Tire & Rubber | Production of dry nu, nu-diisopropyl-2-benzothiazolesulfenamide |
| NO277976L (en) * | 1961-05-03 | |||
| US3144652A (en) * | 1961-11-17 | 1964-08-11 | Monsanto Co | Manufacture of sulfenamides from morpholines |
| US3178428A (en) * | 1961-11-17 | 1965-04-13 | Monsanto Co | Making sulfenamides from morpholines |
-
1978
- 1978-04-13 DE DE19782815964 patent/DE2815964A1/en not_active Withdrawn
-
1979
- 1979-03-31 EP EP79100983A patent/EP0004896B1/en not_active Expired
- 1979-03-31 DE DE7979100983T patent/DE2960363D1/en not_active Expired
- 1979-04-10 ES ES479471A patent/ES479471A1/en not_active Expired
- 1979-04-11 AU AU45930/79A patent/AU517673B2/en not_active Ceased
- 1979-04-11 JP JP4312979A patent/JPS54135781A/en active Granted
- 1979-04-11 CA CA325,292A patent/CA1129860A/en not_active Expired
- 1979-04-11 BR BR7902255A patent/BR7902255A/en unknown
- 1979-04-12 ZA ZA791766A patent/ZA791766B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6149310B2 (en) | 1986-10-29 |
| AU4593079A (en) | 1979-10-18 |
| BR7902255A (en) | 1979-12-11 |
| DE2815964A1 (en) | 1979-10-18 |
| ES479471A1 (en) | 1979-07-16 |
| DE2960363D1 (en) | 1981-08-27 |
| ZA791766B (en) | 1980-05-28 |
| EP0004896B1 (en) | 1981-05-20 |
| EP0004896A1 (en) | 1979-10-31 |
| AU517673B2 (en) | 1981-08-20 |
| JPS54135781A (en) | 1979-10-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |