Перейти к содержанию
Форум химиков на XuMuK.ru

s324

Участник
 Профиль  Обзор контента

  • Постов

    2271

  • Зарегистрирован

  • Посещение

  • Победитель дней

    9

 Тип контента 

Сообщения, опубликованные s324

    как из м-нитроанилину синтезировать м-толуиловую кислоту?

    в Решение заданий

    Получение борэтаноламина.

    в Органическая химия

    Опубликовано

    Boratrane N(CH2CH2O)3B. A mixture of triethanolamine (7.46 g, 50 mmol) and boric acid (3.09 g, 50 mmol) in H2O (3 ml) was stirred with a magnetic stirrer and heated to reflux. Upon cooling, precipitation of white crystals began at 60°C and was over at room temperature in 10 min. The wet precipitate was filtered and dried at reduced pressure (53 mbar) for 1 h or in a vacuum desiccator over P2O5 for 30 min to afford almost pure boratrane. A shorter time was required for drying when crude boratrane was washed with acetone. Yield: 7.84 g (100%). Colorless crystals. Mp 237-238°C; after recrystallization from MeCN mp 239-240°C. IR spectrum, ν, cm-1: 1372 (B-O), 1261 (N→B), 1118, 1083 (C-O), 932 (C-C), 892 (N-C), 620 (B-O), 514 (N→B). 1H NMR spectrum, δ, ppm: 3.95 (6H, CH2O); 3.08 (6H, NCH2). 13C NMR spectrum, δ, ppm: 62.0 (CH2O); 59.3 (NCH2). 15N NMR spectrum, δ, ppm: -335.8. Found, %: C 45.95; H 7.52; B 6.94; N 9.07. C6H12BNO3. Calculated, %: C 45.91; H 7.71; B 6.89; N 8.92.

     

    Based on all the results above, we have got the best reaction conditions for the preparation of triethanolamine borate: optimum deaquation reagent amount 25ml toluene, mole ratio of reactants 1:1(boric acid: triethanolamine) reaction time 2h. The yield of triethanolamine borate is up to 82.46%.

     

    Synthesis of Silatrane via Boratrane: To a 25 mL flask was added boric acid (50 mmol) and triethanolamine (50 mmol). Water (3 mL) was added to facilitate solubility. The flask was equipped with a short path distillation apparatus and heated to 120 °C until no more water condensed. The isolated boratrane was recrystallized from acetonitrile and used directly in the next step. The experimental data collected are in agreement with those described in the literature.[1] 70 %. 1 H NMR (500 MHz, CDCl3): δ = 3.65 (t, J = 5.5 Hz, 6 H), 3.04 (t, J = 5.5 Hz, 6 H). 13C NMR (125 MHz, CDCl3) 62.1, 59.3. IR (ATR) 2988, 2853, 1469, 1370, 1258, 1160, 1115, 1063, 1026, 1001, 933, 889, 730, 621, 560.

    Декарбоксилирование иботеновой кислоты

    в Органическая химия

    Опубликовано · Изменено пользователем s324

    все вже вивчено до вас ))

    http://www.tandfonline.com/doi/abs/10.1081/SCC-200051704

     

    However, and perhaps even more important, the use of 3 H2O (in lieu of water) with DMSO dramatically accelerates the decarboxylation process.

     

    заливай мухомори димексидом !!!!

    був бояришник, ще буде мухоморищник ))

    • Like 2

    Применение тетрабутиламмония бромида при синтезе бензойной кислоты

    в Органическая химия

    Опубликовано

    По моих наблюдениях ТБАБ при окислении перманганатом мало чем помогает.

    Тут главное сначала растворить перманганат в горячей воде и приливать порциями его к раствору субстрата в ацетоне, коего надо раза в два больше воды.

    или, если субстра дубовый и не растворяется в смеси ацетон вода, сделать сухой Bu4N+MnO4-

    и вести окисление в ацетонитриле или пиридине

    Синтез хелатирующих агентов

    в Синтез соединений

    Опубликовано · Изменено пользователем s324

    Organic & Biomolecular Chemistry, 15(14), 2919-2922; 2017

    Jpn. Kokai Tokkyo Koho (2004), JP 2004155718 A Jun 03, 2004. 

    Izvestiya Akademii Nauk, Seriya Khimicheskaya, (9), 2347-2349; 1996

    WO 2011016440 A1 Feb 10, 2011. 

    A 100 ml round bottom flask containing 3-mercapto-1,2-propanediol (Compound I, 1 g, 9.26 mmol) in 5 ml of water was placed in an ice-bath. To this rapidly stirring flask, hydrogenperoxide (exactly 0.5 mole equivalent, 525 μl, 4.63 mmol) was dropwise added while maintaining the temperature between 30-40°C. At the end of the exothermic process, the reaction was allowed to stir overnight at room temperature. Water was azeotroped with rotary evaporation by successive addition of acetonitrile in 20 ml aliquots. The process of acetonitrile addition was repeated 34 times or until all water was removed, yielding a clear oil. After scratching the flask with a metal spatula and cooling overnight at -20°C, the oily product solidified (Compound II, rac-3,3'-dithiobis(1,2-propanediol)). The solid was dried in vacuo over P2O5. Chalky solid, yield 630 mg, 63%. 1H NMR (CD3OD, 360 MHz) δ 2.77, 2.95 (2xd, CH2OH, 2H), 3.59 (M, SCH2, 2H), 3.87 (m, CH, 1H) ppm; Rf = 0.60.General/Typical Procedure: [Example 1] To a glass reactor equipped with a reflux condenser, sample inlet, internal cooler, stirring device and solvent was distilled off with an opening and closing cock was charged with 60weight % of hydrogen peroxide solution 295 g (5.20 mol) prepared and 154 g (1.00 mol) of bis(2-hydroxyethyl)disulfide was uniformly added from the sample inlet over 150 minutes and the liquid was stirred. During this time, the temperature of reaction liquid was held at 45 °C by flowing 19 °C cooling water at the flow rate of 140mL/minutes into the condenser. After completion of the addition, the reaction solution temperature was maintained at 50 °C for 2 hours and heated under reflux for 4 hours. During heating under reflux, the nitrogen gas was blown and the portion of steam was evaporated from the reaction system. 55 weight% aqueous solution of isethionic acid was obtained as a product. Purity of the generated isethionic acid was 244 g(1.94 mol) and the yield was 97%. [Example 3] The product was obtained in the same manner as in example 1, instead of bis(2-hydroxyethyl)disulfide 154 g (1.00 mol), bis(2,3-dihydroxypropyl)disulfide 214 g(1.00 mol) was added, the temperature was maintained at 55 °C by flowing 19 °C cooling water at the flow rate of 70mL/minute into the condenser and the temperature was maintained at 75 °C for 2 hours. 61 weight% aqueous solution of sulfopropanediol was obtained as a product. Purity of the generated sulfo-propanediol was 302 g (1.94 mol) and the yield was 97%. In addition to the product, the by-products 1.1weight% of sulfuric acid and 0.14weight% of 1-hydroxy-2-sulfopropionic acid were not confirmed.

     

×
×
  • Создать...