CS259557B1 - Method of 2-mercaptobenzothiazole's oxidation process checking by means of hydrogen peroxide - Google Patents
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Abstract
Riešenie sa týká spósobu kontroly oxidá- cie 2-merkaptobenztlazolu peroxidom vodí- ka v zmesi alifatického alebo alicyklíckého alkoholu s vodou, s obsahom vody 1 až 30 percent hmot., spektrofotometricky. Po odfiltrovaní suspenzie oxidovanej reakčnej zmesi sa z kvapalne] fázy odpipetované množstvo zriedi porovnávacím roztokom a pomocou UV-spektrofotometra sa stanoví koncentrácia 2-merkaptobenztiazolu z ab- sorbancie pri λ = 300 až 350 nm. Ako porovnávací roztok sa použije alifatický alebo alicyklický alkohol (etylalkohol, izopropyl- alkohol, n-butylalkohol, izobutylalkohol, e- ■tylhexanoil alebo cyklohexanolj, vždy však rovnaký, ako rozpúšťadlo použité pri oxidá- cii. Riešenie je možné využit’ v chemickom priemysle.The present invention relates to a method for controlling the oxidation of 2-mercaptobenzothlazole with hydrogen peroxide in a mixture of an aliphatic or alicyclic alcohol with water, with a water content of 1 to 30 percent by weight, spectrophotometrically. After filtering off the oxidized reaction suspension, the liquid phase is diluted with the reference solution and the UV-spectrophotometer is used to determine the concentration of 2-mercaptobenzothiazole from absorbance at λ = 300-350 nm. The reference solution used is an aliphatic or alicyclic alcohol (ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, ethylhexanoil or cyclohexanol, but always the same as that used in the oxidation. The solution can be used in the chemical industry.
Description
Vynález; sa týká spůsobu kontroly procesu oxidácie 2-merkaptobenztiazolu peroxidom yodíka v zmesi alifatického alebo allcyklického .alkoholu a vody s obsahom vody 1 .až 30 % hmo.Invention; relates to a process for controlling the oxidation process of 2-mercaptobenzothiazole with hydrogen peroxide in a mixture of an aliphatic or allcyclic alcohol and water having a water content of 1 to 30% by weight.
2,2‘-Dibenztiazyldisulfid sa .připravuje oxidačnou reakciou 2-merkaptobenztiazolu vodným roztokom peroxidu vodíka podl'a schémy o2,2'-Dibenzothiazyl disulphide is prepared by the oxidative reaction of 2-mercaptobenzothiazole with an aqueous solution of hydrogen peroxide according to Scheme 2.
Z.OF.
íC-SH f s'' i iiC-SH f i i
N, c-s-s-c;· jQH/ícN, C-s-s-c;
Je všeobecne známe, že pri výrobě urých1'ovačov v.ulkanizácie kaučuku je potřebné viesť proces oxidácie v oblasti optimálneho molárneho poměru základných zložiek 2-merkaptobenztiazolu a peroxidu vodíka, a to z hfadiska selektívnosti reakcie ako aj z hfadiska akosti finálneho produktu.It is well known that in the manufacture of rubber vulcanization accelerators it is necessary to conduct the oxidation process in the region of the optimum molar ratio of the 2-mercaptobenzothiazole and hydrogen peroxide constituents, both in terms of selectivity of reaction and in terms of quality of the final product.
Klasické postupy stanovenia., tzv. „konca •oxidácie“ v procesoch oxidácie tohoto typu sú založené na kvalitatívnych technických stanoveniach nadbytku oxidačného činidla, např. jodoškřobovým papierom.Classical methods of determining the so-called "end • of oxidation" in oxidation processes of this type are based on qualitative technical determinations of excess oxidant, eg by iodine scrap paper.
Tieto postupy nemožno použif v případe oxidačného. procesu uskutečňovaného nepřetržitým sposobom.These procedures cannot be used in the oxidation case. a continuous process.
Kontrola oxidačného. procesu meraním redox-potenciálu oxidoredukčnej sústavy nevedie k získaniu reprodukovateíných a interpretovateíných výsledkov.Oxidation control. process by measuring the redox potential of the oxidoreduction system does not produce reproducible and interpretable results.
Teraz sa zistilo, že je možné kontrolovat proces oxidácie 2-merkaptobenztiazolu peroxidom vodíka v zmesi alifatického alebo alicyklického alkoholu s vodou, s obsahom vody 1 až 30 % hmot., spektrofotometricky sposobom pódia vynálezu.It has now been found that it is possible to control the oxidation process of 2-mercaptobenzothiazole with hydrogen peroxide in a mixture of an aliphatic or alicyclic alcohol with water, with a water content of 1 to 30% by weight, spectrophotometrically according to the invention.
Podstata vynálezu spočívá v tom, že po odfiltrovaní suspenzie oxidovanej reakčnej zmesi sa z kvapalnej fázy odpipetované množstvo zriedi porovnávacím roztokom a UV-spektrom sa stanoví koncentrácia 2-merkaptobenztiazolu z absorbancie pri λ — = 300 až 350 nm, pričom ako porovnávací roztok sa použije .alifatický alebo alicyklický alkohol zo skupiny zahrňujúcej:According to the invention, after filtering off the suspension of the oxidized reaction mixture, the pipette is diluted from the liquid phase with a reference solution and the concentration of 2-mercaptobenzothiazole is determined from the absorbance at λ = 300-350 nm using the UV spectrum. an aliphatic or alicyclic alcohol selected from the group consisting of:
etylalkohol, izopropylalkohol, •n-butylalkohol, izobutylalkohol, etylhexanol a cyklohexanol vždy však rovnaký ako použité rozpúšthdla pri oxidácii.however, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, ethylhexanol and cyclohexanol are always the same as the solvents used in the oxidation.
Proces oxidácie 2-merkaptobenztiazolu peroxidom vodíka sa kontroluje pomocou .stanovenia koncentrácie 2-merkaptobenztiazolu v kvapalnej fáze oxidačnej zmesi po spotřebovaní peroxidu vodíka v oxidačnej reakcii.The process of oxidizing 2-mercaptobenzothiazole with hydrogen peroxide is controlled by determining the concentration of 2-mercaptobenzothiazole in the liquid phase of the oxidation mixture after the consumption of hydrogen peroxide in the oxidation reaction.
Suspenzia oxidačnej zmesi sa odfiltruje. Filtrát obsahuje 1 až 30 % vody, 0,05 až 1 percento 2-merkaptobenztiazolu, 0,005 až 1 percento benztlazyl-2-sulfónovej kyseliny a 68 až 99 % alkoholu podlá stupňa naoxidovania reakčnej zmesi.The oxidation slurry was filtered off. The filtrate contains 1 to 30% water, 0.05 to 1 percent 2-mercaptobenzothiazole, 0.005 to 1 percent benztlazyl-2-sulfonic acid and 68 to 99% alcohol according to the degree of oxidation of the reaction mixture.
Z filtrátu oxidačnej zmesi sa odpipetuje potřebné množstvo a po zriedení porovnávacím roztokom 1 : 25 až 1:2 500 sa UV-spektrometricky voči porovnávaciemu roztoku odmeria absorbancia při λ = 300 až 350 nm.Pipette the necessary amount from the oxidation mixture filtrate and, after dilution with reference solution 1: 25 to 1: 2500, measure the absorbance at λ = 300 to 350 nm by UV-spectrometry against the reference solution.
Ako porovnávací roztok možno použif buď izopropylalkohol, tiež cyklohexanol, alebo etanol, príp. n-butylalkohol, resp. izobutylalkohol alebo etylhexanol, pričom musí byť zvolený vždy taký z alifatických alebo alicyklických alkoholov, ktorý bol použitý ako rozpúšťadlo pri oxidačnej reakcii 2-merkaptobenztiazolu s vodným roztokom peroxidu vodíka.Either isopropanol, also cyclohexanol or ethanol or the like can be used as reference solution. n-butyl alcohol, respectively. isobutyl alcohol or ethylhexanol, the aliphatic or alicyclic alcohols used as solvent in the oxidation reaction of 2-mercaptobenzothiazole with aqueous hydrogen peroxide.
Koncentrácia 2-merkaptobenztiazolu sa vypočítá na základe vztahu z . A = c . d . a ako.The concentration of 2-mercaptobenzothiazole is calculated based on z. A = c. d. and how.
z. A kde c je híadaná koncentrácia 2-merkaptobenztiazolu v mól. dm-3, z je stupeň zriedenia, ktorého hodnota je 25 až 2 500,and wherein c is the desired concentration of 2-mercaptobenzothiazole in mol. dm -3 , z is the dilution degree of 25 to 2 500,
A je meraná absorbencia pri λ = 330 nm charakteristická pre 2-merkaptobe.nztiazol, d je hrúbka použitej kyvety v cm .a a je mólový absorpčný koeficient, ktorý má pre 2-merkaptobonztiazol pri λ — 290 až 320 nm hodnoty pre izopropylalkohol:A is the absorbance at λ = 330 nm characteristic of 2-mercaptobenzothiazole, d is the thickness of the cuvette used in cm .a and is the molar absorption coefficient having 2-mercaptobonzothiazole at λ - 290 to 320 nm for isopropyl alcohol:
2,59.1O4 dm3. . cm-1,2,59.1O 4 dm 3 . . cm -1 ,
c‘ (%) = --(mól. dm-3] . mól. hmotnostc '(%) = - (mol. dm -3 )
2-merkaptobenztiazolu2-mercaptobenzothiazole
Stupeň zvoleného zriedenia závisí od koncentrácie 2-merkaptoben,ztiazolu vo vzorke, od hrůbky použitej kyvety a musí byť zvolený tak, aby meraná hodnota absorbancie bola v rozmedzí A — 0,8 až 1,2, čím je zaručená najvyššia přesnost a citlivost merania.The degree of dilution chosen depends on the concentration of 2-mercaptoben, thiazole in the sample, the depth of the cuvette used and must be chosen so that the absorbance measured is in the range of A - 0,8 to 1,2, thus guaranteeing the highest measurement accuracy and sensitivity.
Množstvo stanoveného 2-merkaptobenztiazolu charakterizuje koncentrácia 2-merkaptobenztiazolu vo filtráte v rozmedzí 1 až 4 % z množstva do reakcie vstupuj,úceho. Ak je koncentrácia 2-merkaptobenztiazolu vo filtráte .nižšia ako 1 % z množstva do reakcie vstupujúceho, v oxidačnej zmesi, převažuje oxidačně činidlo. Ak je koncentrácia 2-merkaptobenztiazolu vo filtráte vyššia ako 4 % z množstva do reakcie vstupujúceho v oxidačnej zmesi, je nedostatok oxidačného činidla.The amount of 2-mercaptobenzothiazole determined is characterized by a concentration of 2-mercaptobenzothiazole in the filtrate ranging from 1 to 4% of the amount of reaction to be reacted. When the concentration of 2-mercaptobenzothiazole in the filtrate is less than 1% of the amount entering the reaction, in the oxidation mixture, the oxidizing agent predominates. If the concentration of 2-mercaptobenzothiazole in the filtrate is greater than 4% of the amount entering the reaction in the oxidation mixture, there is a lack of oxidizing agent.
Výhoda analytickej kontroly procesu oxidačně j reakcie 2-merkaptobenztiazolu vodným roztokom peroxidu vodíka v prostředí zmesi alifatického alebo alicyklického alkoholu a vody ipodla vynálezu spočívá v možnosti udržať proces oxidačnej reakcie v oblasti optimálnych pomerov 2-merkaptobenztiazolu a oxidačného činidla a tým eliminovat vplyv ako poruch dávkovačích zariadení, tak chýb pri přípravě zásobných roztokov reakčných komponentoví na výťažnosť oxidačného procesu a akosti finálneho produktu.The advantage of analytical control of the oxidation reaction process of 2-mercaptobenzothiazole with an aqueous solution of hydrogen peroxide in an aliphatic or alicyclic alcohol / water mixture according to the invention lies in the ability to maintain the oxidation reaction process at optimal ratios of 2-mercaptobenzothiazole and oxidizing agent and errors in the preparation of stock solutions of the reaction components for the yield of the oxidation process and the quality of the final product.
Uvedené příklady objasňujú, ale neohmedzujú predmet vynálezu.These examples illustrate, but do not limit the scope of the invention.
Příklad 1Example 1
Suspenzia oxidovanej reakčnej zmesi, obsahujúca produkt oxidácie a etylhexanol nasýtený vodou ako kvapalnú fázu, sa odfiltroval cez fritu (S-3j. Z filtrátu sa odpipetovalo 0,1 ml kvapaliny do odmernej banky a zriedil sa obsah porovnávacím roztokom do objemu 10 iml. V 1 cm kyvetách sa odmerala absorbancia pri λ = 300 nm proti porovnávaciemu roztoku a vypočítalo sa množstvo 2-merkaptobenztiazolu přítomné vo filtráte. Ako porovnávací roztok sa použil etylhexanol.The oxidized reaction mixture suspension, containing the oxidation product and ethylhexanol saturated with water as the liquid phase, was filtered through a frit (S-3j). 0.1 ml of liquid was pipetted from the filtrate into a volumetric flask and diluted to 10 µl with reference solution. The absorbance at λ = 300 nm against the reference solution was measured in cm cells and the amount of 2-mercaptobenzothiazole present in the filtrate was calculated using ethylhexanol as the reference solution.
Množstvo nájdeného 2-merkaptobenztiazolu bolo 4,4. ΙΟ-3 mól. dm-3, t. j. 2,2 % z množstva 0,2 mól. dm-3 2-merkaptobenztiazolu do' reakcie vstupujúceho.The amount of 2-mercaptobenzothiazole found was 4.4. ΙΟ -3 mol. dm -3 , ie 2.2% of 0.2 mol. dm -3 of 2-mercaptobenzothiazole in the reaction of the incoming.
V oxidačnoím procese bolí zachované optimálně poměry oxidačného činidla a látok oxidovatelných.In the oxidation process, the proportions of oxidizing agent and oxidizable substances are maintained optimally.
Příklad 2Example 2
Suspenzia oxidovanej reakčnej zmesi obsahujúca ako hlavný podiel kvapalnej fázy etanol sa odfiltrovala cez fritu (S-3). Z filtrátu sa odipipetovalo 0,2 ml kvapaliny do odmernej banky a obsah sa zriedil porovnávacím roztokom do objemu 250 ml. V 2 centimetrových kyvetách sa odmerala absorbancia pri λ = 320 nm proti porovnávaciemu roztoku a vypočítalo sa množstvo 2-merkaptobenztiazolu přítomné vo filtráte. Ako porovnávací roztok sa použil etanol. Množstvo nájdeného 2-merkaptobenzthiazolu bolo 0,0)2 mól. dm'3, t. j. 10 % z množstva 0,2 mól. dm-3 2-merkaptobenztiazolu do reakcie vstupujúceho. Aby holi dodržané optimálně poměry oxidačného činidla a látok oxidovatelných, třeba do procesu oxidácie přidat' .naviac 11 % peroxidu vodíka. Příklad 3The oxidized reaction mixture slurry containing ethanol as the major portion of the liquid phase was filtered through a frit (S-3). 0.2 ml of liquid was pipetted from the filtrate into a volumetric flask and diluted to 250 ml with reference solution. Absorbance at λ = 320 nm was measured in 2 cm cuvettes against the reference solution and the amount of 2-mercaptobenzothiazole present in the filtrate was calculated. Ethanol was used as reference solution. The amount of 2-mercaptobenzthiazole found was 0.0 12 mole. dm- 3 , i.e. 10% of the amount of 0.2 mol. dm -3 of 2-mercaptobenzothiazole in the reaction of the incoming. In order to maintain optimum ratios of oxidizing agent and oxidizable substances, more than 11% hydrogen peroxide must be added to the oxidation process. Example 3
Suspenzia oxidovanej reakčnej zmesi obsahujúca produkt, n-butylalkohol a 10 % hmot. vody sa odfiltrovalo cez fritu (S-3). Z filtrátu sa odipipetovalo 1,5 ml kvapaliny do odmernej banky a obsah sa zriedil porovnávacím roztokom do objemu 25 ml. V 0,5 cm kyvetách sa odmerala absorbancia pri λ — 315 nm proti porovnávaciemu roztoku a vypočítalo sa množstvo 2-merkaptobenztiazolu přítomné vo filtráte. Ako porovnávací roztok sa použil n-butylalkohol.An oxidized reaction mixture suspension containing the product, n-butyl alcohol and 10 wt. water was filtered through a frit (S-3). 1.5 ml of liquid was pipetted from the filtrate into a volumetric flask and diluted to 25 ml with reference solution. Absorbance at λ - 315 nm against the reference solution was measured in 0.5 cm cuvettes and the amount of 2-mercaptobenzothiazole present in the filtrate was calculated. N-Butyl alcohol was used as reference solution.
Množstvo nájdeného 2-merkaptobenztiazolu bolo 1.1O-3 mól. dm-3, t. j. 0,5 % z množstva 0,2 imól. dm-3 2-merkaptobenztiazolu do reakcie vstupujúceho.The amount of 2-mercaptobenzothiazole found was 1.10 -3 mol. dm -3 , ie 0.5% of the amount of 0.2 imol. dm -3 of 2-mercaptobenzothiazole in the reaction of the incoming.
Aby boli dodržané optimálně poměry oxidačného činidla a látok oxidovatelných je potřebné do reakčnej zmesi přidávat o 5 °/o peroxidu vodíka menej.In order to maintain optimal ratios of oxidizing agent and oxidizable substances, it is necessary to add 5% less hydrogen peroxide to the reaction mixture.
P r í k 1 a d 4Example 1 4
Suspenzia oxidovanej reakčnej zmesi obsahujúca ako hlavný kvapalný podiel izobutylalkohol, sa odfiltrovala cez fritu (S-3). Z filtrátu sa odpipetovalo 0,2 ml kvapaliny do cdmernej banky a zriedil sa obsah po7 rovnávacím roztokom do objemu 500 ml. V 1 cm kyvetách sa odmerala absorbancia pri λ = 320 nm proti porovnávacím roztokom a vypočítalo sa množstvo 2-merkaptobenztiazolu přítomné vo filtráte.The oxidized reaction mixture slurry containing isobutyl alcohol as the major liquid portion was filtered through a frit (S-3). 0.2 ml of the liquid was pipetted from the filtrate into a cdmer flask and diluted with 500 ml of the equalizing solution. Absorbance at λ = 320 nm was measured in 1 cm cuvettes against the reference solutions and the amount of 2-mercaptobenzothiazole present in the filtrate was calculated.
Ako porovnávací roztok sa použil izobutylaikohol. Množstvo néjdeného 2-merkaptobenztiazolu bolo 0,048 mól. drn-3, t. j. 8 % z množstva 0,6 mgl. dm-3 2-merkaptobenztiazolu do reakcie vstupujúceho.Isobutyl alcohol was used as reference solution. The amount of 2-mercaptobenzothiazole not found was 0.048 mol. drn -3 , ie 8% of 0.6 mgl. dm -3 of 2-mercaptobenzothiazole in the reaction of the incoming.
Aby boli dodržené optimálně ipomery oxidačného činidla a látok oxidovateíných, třeba do procesu oxidácie pridať naviac 8,5 percent peroxidu vodíka.In addition, 8.5 percent of hydrogen peroxide should be added to the oxidation process in order to optimally maintain the ipomers of the oxidizing agent and the oxidizable substances.
Příklad 5Example 5
Suspenzia oxídovanej reakčnej zmesi obsahujúca ako hlavný kvapalný podiel cyklohexanol sa odfiltrovala cez fritu (S-3). Z filtrátu sa odpipetovalo 0,3 ml kvapaliny do odmernej banky a obsah sa zriediil porovnávacím roztokom do objemu 25 ml. V 0,5 cm kyvetách sa odmerala absorbancia pri λ = = 340 nm proti porovnávaciemu roztoku a vypočítalo sa množstvo 2-merkaptobenztiazolu přítomné vo filtráte.The oxidized reaction mixture slurry containing cyclohexanol as the major liquid portion was filtered through a frit (S-3). 0.3 ml of liquid was pipetted from the filtrate into a volumetric flask and diluted to 25 ml with reference solution. Absorbance at λ = 340 nm was measured in 0.5 cm cuvettes against the reference solution and the amount of 2-mercaptobenzothiazole present in the filtrate was calculated.
Áko porovnávací roztok sa použil cyklohexanol. Množstvo néjdeného 2-merkaptobenztiazolu bolo 5.10-2 mól. dm-3, t. j. 2,5 percent z množstva 2,0 mól. dm-3 2-merkaptobenztiazolu do reakcie vstupujúceho.Cyclohexanol was used as the reference solution. The amount of 2-mercaptobenzothiazole not found was 5.10 -2 mol. dm -3 , ie 2.5 percent of 2.0 mol. dm -3 of 2-mercaptobenzothiazole in the reaction of the incoming.
V oxidačnom procese boli zachované optimálně poměry oxidačného činidla a látok oxidovateíných.In the oxidation process, the ratios of the oxidizing agent and the oxidizable substances were optimally maintained.
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| CS866570A CS259557B1 (en) | 1986-09-11 | 1986-09-11 | Method of 2-mercaptobenzothiazole's oxidation process checking by means of hydrogen peroxide |
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| CS866570A CS259557B1 (en) | 1986-09-11 | 1986-09-11 | Method of 2-mercaptobenzothiazole's oxidation process checking by means of hydrogen peroxide |
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| CN108727302A (en) * | 2017-10-23 | 2018-11-02 | 科迈化工股份有限公司 | A kind of environment-friendly type N tert butyl benzothiazole 2 sulfenamide（NS）Synthesis technology |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108727302A (en) * | 2017-10-23 | 2018-11-02 | 科迈化工股份有限公司 | A kind of environment-friendly type N tert butyl benzothiazole 2 sulfenamide（NS）Synthesis technology |
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