RU2034836C1 - Process for preparing n-(cylohexylthio) phthalimido - Google Patents

Abstract

FIELD: organic chemistry. SUBSTANCE: the product is N- (cyclohexylthio) phthaelimide, m p 93094 C. Reagent 1 : dicyclohexyl disulfide. Reagent 2: a potassium phthalimide suspension. Reaction conditions: heating in carbon tetrachloride. Reagent 1 is previously prepared by reacting cyclohexyl chloride with 1/2 part of the previously prepared aqueous solution of sodium sulfide and sulfur in the presence of an emulsifier first of boiling then at 93-77 C, followed by addition the remaining portion of said aqueous solution. The mixture is then kept at the reaction temperature and the oil layer is separated. The layer is separated by extraction with carbon tetrachloride. The resulting solution of reagent 1 (after chlorine is allowed to pass through it) is added to the suspension of reagent 2. The yield is 90%. EFFECT: improved preparation process.

Description

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N

который находит применение в качестве замедлителя преждевременной вулканизации резиновых смесей.The invention relates to an improved method for producing N- (cyclohexylthio) phthalimide of the formula I

S

N

which is used as a moderator of premature vulcanization of rubber compounds.

 The aim of the invention is to simplify the process and improve the quality of the target product.

A known method of producing N- (cyclohexylthio) phthalimide by the interaction of dicyclohexyl disulfide (II) with potassium (III) phthalimide in a non-polar solvent, for example CCl ₄ in the presence of chlorine, in a molar ratio of II: III 1: 2, chlorine is added in the ratio II: chlorine 1: 1, whereby the temperature increases to 40 ^{° C} and then the reaction mixture was stirred at 20-40 ^{° C} for 20-240 min. The yield of the target product 91-92% [1]
The disadvantage of this method is the complexity of the process associated with the use of pure dicyclohexyl disulfide, as well as the need to accurately conduct the process with a ratio of potassium phthalimide: dicyclohexyl disulfide: chlorine strictly equal to 2: 1: 1.

Closest to the proposed is a method for producing N- (cyclohexylthio) phthalimide of the formula I by reacting dicyclohexyl disulfide II with potassium phthalimide III in a molar ratio of II: III1: 2 in CCl ₄ , in the presence of chlorine taken in a molar ratio of II: chlorine of 1: 1. To a suspension of II and III in CCl ₄ at 5-30 ^C. was added a solution of chlorine in CCl ₄ for 30-60 minutes and then the mixture was stirred for 30-180 min at 20-60 ^C. The KCl precipitate was filtered off, the filtrate was washed with CCl ₄ , the solvent is concentrated to 10-20% of the initial volume and the target product is planted with hexane, pentane or benzyl. Yield 83-91.13% Content of the main product 93-95.5% [2]
The disadvantage of this method is the complexity of the process associated with the use of pure dicyclohexyl disulfide, as well as the need to accurately conduct the process with a ratio of potassium phthalimide: dicyclohexyl disulfide: chlorine, respectively, equal to 2: 1: 1, which is very difficult in the production conditions. In addition, during the process, cyclohexyl sulfochloride is obtained directly in the medium of potassium phthalimide, which can lead to an intense uncontrolled reaction with a large heating and release of the reaction mass.

It is also known that ditsiklogeksildisulfid hlortsiklogeksina prepared by reaction with Na ₂ S and sulfur in an aqueous medium at 95 ° ^C followed by separation of the oil layer, washing it with 10% aqueous NaCl and distilling off the volatile part at ¹⁰⁰ ° C / 40 mmHg and subsequent treatment with copper powder at 100 ^about C for 4 hours. The yield of the target product 70.4% [3]
Disadvantages of the known method are eliminated by the proposed method obtaining N- (cyclohexylthio) phthalimide, consisting in that ditsiklogeksildisulfid tsiklogeksilhlorida previously prepared by reaction with Na ₂ S and sulfur in an aqueous medium at a temperature of 93-97 ^{° C,} followed by separation of the organic from the aqueous layer. The organic layer was extracted with CCl ₄ ^- . The resulting solution was cooled ^to 0 ° C, with stirring passed chlorine, then the solution was added to a suspension of potassium phthalimide in CCl _4, stirred for 1 h at room temperature and heated ^at 40 ° C for 1 hour. The product is isolated in a known manner. The content of the main substance is 97-98%
The difference of the proposed method is the preliminary preparation of dicyclohexyl disulfide by the interaction of cyclohexyl chloride with Na ₂ S and sulfur in an aqueous medium with separation of the oil layer and extraction of its CCl ₄ .

After the solution thus obtained was passed chlorine at ⁰ ° C and then poured into a slurry of potassium phthalimide and the mixture allowed to stand 1 hour at room temperature and 1 hour at 40 ° ^C.

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5,85 г Na₂S (0,075 моля) (см. примечание 1) растворяют при интенсивном перемешивании и кипячении в 20 мл воды в двухгорлой колбе, снабженной мешалкой и обратным холодильником. Затем добавляют 2,4 г (0,075 моля) серы, перемешивают при кипячении до получения гомогенного раствора. Раствор охлаждают до 50-60^оС (охлаждение не обязательно) и половину его отливают в стакан. К оставшемуся раствору в колбе добавляют 2,37 г эмульгатора ОП-7 (20% вес. от массы хлорциклогексана), затем при перемешивании и нагревании (температура 95^оС) по каплям добавляют 11,85 г (0,1 моль) хлорциклогексана (в течение 1 ч). После добавки хлорциклогексана смесь перемешивают при нагревании (температура 96^оС) в течение 7 ч. Затем к реакционной смеси добавляют отобранную часть раствора дисульфида натрия и нагревают при перемешивании еще 4 ч. После окончания реакции масляный слой отделяют от водного и промывают 10 мл воды. Воду отделяют и масляный слой экстрагируют ССl₄ (3 х 25 мл). Полученный раствор циклогексилдисульфида в 75 мл ССl₄ используют в стадии получения N-(циклогексилтио)фталимида (Y).Method for producing cyclohexyl disulfide (III)

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5.85 g of Na ₂ S (0.075 mol) (see Note 1) is dissolved with vigorous stirring and boiling in 20 ml of water in a two-necked flask equipped with a stirrer and reflux condenser. Then, 2.4 g (0.075 mol) of sulfur are added, and they are stirred at the boil until a homogeneous solution is obtained. The solution was cooled to 50-60 ^{° C} (cooling not necessary) and half of it was cast into a glass. To the residual solution in the flask was added 2.37 g of emulsifier OP-7 (20 wt.% By weight of hexachlorocyclohexane), followed by stirring and heating (temperature 95 ° ^C) was added dropwise 11.85 g (0.1 mol) chlorocyclohexane ( within 1 h). After addition chlorocyclohexane mixture was stirred under heating (temperature 96 ^{° C)} for 7 hours. Then the reaction mixture was added a selected portion of the solution of sodium disulfide and heated with stirring a further 4 hours. After the reaction, the oil layer was separated from water and washed with 10 ml of water. The water was separated and the oil layer was extracted with CCl ₄ (3 x 25 ml). The resulting solution of cyclohexyl disulfide in 75 ml of CCl _{4 is} used in the preparation of N- (cyclohexylthio) phthalimide (Y).

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+ KN

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N

а) В четырехгорлую колбу, снабженную мешалкой, термометром, капилляром для пропускания хлора и хлоркальциевой трубкой помещают 30 мл ССl₄, охлаждают до 0^оС и при перемешивании пропускают хлор до привеса 2,5 г (количество Сl₂ в ССl₄ определяют либо взвешиванием, либо йодометрическим титрованием). Полученный раствор хлора в ССl₄ подают на стадии хлорирования дисульфида (III). б) (сравнительный пример). В трехгорлую колбу, снабженную мешалкой и термометром, помещают раствор дициклогексилдисульфида в 75 мл ССl₄, полученный на стадии II и 13,0 г (0,07 моля) фталимида калия. И при интенсивном перемешивании при 20-28оС по каплям подают раствор хлора в ССl₄. Раствор хлора подают в течение 1-1,5 ч. Скорость подачи раствора хлора регулируется по температуре реакции. После подачи раствора хлора реакционную смесь перемешивают сначала при комнатной температуре в течение 1 часа, затем температуру повышают до 40^оС и при этой температуре реакционную смесь перемешивают еще 1 ч. После чего реакционную смесь охлаждают до комнатной температуры и фильтруют. Твердый осадок на фильтре промывают 30 мл ССl₄, растворы объединяют и растворитель отгоняют до половины первоначального объема. Остаток охлаждают до 0^оС, прибавляют 150 мл р-гептана (или 100-120 мл бензил-калоша) и выпавший осадок фильтруют. Получают 16,34 г N-(циклогексилтио)фталимида в виде бесцветных кристаллов. Кристаллизуют из гептана, т. пл. 93-94^оС. Выход 90% Содержание основного вещества 95,5% в). Раствор хлора, полученный на стадии а) прикапывают к раствору дициклогексилдисульфида при 0^оС и затем приливают полученный раствор к суспензии 13 г (0,07 моля) фталимида калия в 30 мл ССl₄ ^- и нагревают раствор до 40^оС. При 40^оС реакционную смесь перемешивают в течение 3 ч. Затем реакционную смесь фильтруют, отгоняют растворитель до половины первоначального объема и прибавляют 150 мл н-гептана. Выпавший осадок фильтруют. Получают 16,34 г N-(циклогексилтио)-фталимида в виде бесцветных кристаллов. Перекристаллизовывают из гептана, т.пл. 93-94^оС. Выход 90% содержание основного вещества 97%
Таким образом, предложенный способ позволяет существенно упростить процесс. Отпадает необходимость предварительного выделения и очистки дициклогексилдисульфида, не нужно предварительно получать раствор хлора в ССl₄ с точной концентрацией. Исчезает возможность неконтролируемой экзотермической реакции, при одновременном улучшении качества продукта. Содержание основного вещества увеличивается с 93-95,5% до 97-98%Method for the preparation of N- (cyclohexylthio) phthalimide (Y)

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+ KN

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N

a) To a four-necked flask equipped with a stirrer, a thermometer, a capillary for the transmission of chlorine and calcium chloride drying tube was placed 30 ml of CCl ₄ was cooled ^to 0 ° C and under stirring chloro passed to gain 2.5 g (amount of Cl ₂ or CCl ₄ determined by weighing or iodometric titration). The resulting solution of chlorine in CCl _{4 is} fed to the stage of chlorination of disulfide (III). b) (comparative example). In a three-necked flask equipped with a stirrer and a thermometer, a solution of dicyclohexyl disulfide in 75 ml of CCl ₄ , obtained in stage II and 13.0 g (0.07 mol) of potassium phthalimide, is placed. And with vigorous stirring at 20-28 ° C, a solution of chlorine in CCl _{4 is} added dropwise. The chlorine solution is supplied for 1-1.5 hours. The feed rate of the chlorine solution is controlled by the reaction temperature. After chlorine feed solution, the reaction mixture was stirred first at room temperature for 1 hour, then the temperature was raised ^to 40 ° C and at this temperature the reaction mixture was stirred for a further 1 hour. After the reaction mixture was cooled to room temperature and filtered. The filter cake is washed with 30 ml of CCl ₄ , the solutions are combined and the solvent is distilled off to half the original volume. The residue was cooled ^to 0 ° C, was added 150 ml of p-heptane (or 100-120 ml of benzyl galosh) and the precipitate filtered. 16.34 g of N- (cyclohexylthio) phthalimide are obtained in the form of colorless crystals. Crystallized from heptane, so pl. 93-94 ^C. Yield: 90% Content of the basic substance in 95.5%). A solution of chlorine produced in step a) is added dropwise to a solution of ditsiklogeksildisulfida at ⁰ ° C and then pour the resulting solution to a suspension of 13 g (0.07 mole) of potassium phthalimide in 30 ml of CCl ₄ ^-, and the solution was heated to 40 ° ^{C at} 40 The reaction mixture was stirred for 3 hours. Then the reaction mixture was filtered, the solvent was distilled off to half the original volume and 150 ml of n-heptane were added. The precipitate is filtered. 16.34 g of N- (cyclohexylthio) -phthalimide are obtained in the form of colorless crystals. Recrystallized from heptane, mp. 93-94 ^about C. Yield 90% of the content of the main substance 97%
Thus, the proposed method can significantly simplify the process. There is no need for preliminary isolation and purification of dicyclohexyl disulfide, it is not necessary to first obtain a solution of chlorine in CCl ₄ with an exact concentration. The possibility of an uncontrolled exothermic reaction disappears, while improving the quality of the product. The content of the basic substance increases from 93-95.5% to 97-98%

Claims (1)

METHOD FOR PRODUCING N- (CYCLOHEXYLTHIO) PHTHALIMIDE OF THE FORMULA

the interaction of dicyclohexyl disulfide with a suspension of potassium phthalimide when heated in carbon tetrachloride using chlorine, characterized in that they use dicyclohexyl disulfide obtained by the interaction of cyclohexyl chloride with sodium sulfide and sulfur in an aqueous medium in the presence of an emulsifier at 93-97 ^o C, while cyclohexyl chloride the prepared aqueous solution of sodium sulfide and sulfur, while boiling and after stirring at 93-97 ^o With add the rest of the preliminary preparation an oily solution of sodium sulfide and sulfur, the mixture is kept at the reaction temperature, the oil layer is separated, which is extracted with carbon tetrachloride, and the resulting dicyclohexyl disulfide solution is added to the suspension of potassium phthalimide after passing chlorine through it.