Лабораторная работа 3 – Использование реакции гидроксилирования в производстве фенола.

Анилин 9,3 г

Серная кислота (d=1,84) 10 мл

Нитрит натрия 7,3 г

Эфир 60 мл

Стакан фарфоровый на 250 мл

Круглодонная колба на 500 мл

Воронка капельная

Мешалка

Установка для перегонки с водяным паром

Установка для перегонки фенола с коротким воздушным холодильником

В толстостенный стакан наливают 50 мл воды, при тщательном перемешивании осторожно приливают 190 мл концентрированной серной кислоты и добавляют 9,3 г свежеперегнанного анилина. Раствор охлаждают до 0 ⁰, постепенно добавляя к нему 75 г мелко раздробленного льда при сильном перемешивании, чтобы частично выделяющийся сернокислый анилин был мелкокристаллическим.

К охлажденной смеси из капельной воронки медленно, по каплям, при сильном перемешивании приливают охлажденный до 0 - 5⁰ раствор 7,3 г нитрита натрия в 30 мл воды. Температура реакционной смеси при этом не должна превышать 8 ⁰. Когда основная часть раствора нитрита натрия уже находится в реакционной смеси, прекращают его приливание и через 5 мин берут пробу на присутствие свободной азотистой кислоты. Для этого каплю раствора наносят на иодкрахмальную бумагу. Если на бумаге не появляется синее пятно, значит, нужно продолжать добавление раствора нитрита натрия. Одновременно надо следить за тем, чтобы раствор все время имел кислую реакцию (по конго). Наряду с присутствием свободной азотистой кислоты в растворе признаком конца реакции является полный переход сернокислого анилина в раствор.

Раствор соли диазония переносят в колбу на 500 мл и нагревают на водяной бане (температура бани 50-60 ⁰) до прекращения выделения азота (15-20 мин). Полученный фенол отгоняют с водяным паром до тех пор, пока проба дистиллята не перестанет давать помутнения с бромной водой. Дистиллят насыщают поваренной солью и фенол несколько раз извлекают эфиром (3 раза порциями по 20 мл). Эфирные вытяжки сушат безводным сульфатом натрия или магния. Эфир отгоняют и фенол перегоняют из маленькой колбы, собирая фракцию 179-183 ⁰. После охлаждения фенол должен закристаллизоваться.

Выход фенола около 6 г. Фенол вызывает при попадании на кожу ожоги. Поэтому при работе с ним следует соблюдать осторожность [3].

[3]. Альбицкая В.Г., Гинзбург О.Ф., Коляскина З.Н., Купин Б.С., Павлова Л.А., Разумова Н.А., Ралль К.Б., Серкова В.И., Стадничук М.Д. Лабораторные работы по органической химии. Под ред. О.Ф. Гинзбурга, А.А. Петрова. М.: Высш. шк., 1967. – с. 109-110.

Theme 1 - Methods of chemical reactions that are used in the technique of producing organic compounds (3 hours)

Objective: to consolidate the knowledge taught the basics of chemical transformations of intermediate or final products of production.

Learning objectives: to disassemble the basic types of chemical reactions used for the synthesis of drugs and techniques to apply in the preparation of organic compounds.

The main issue in this topic:
1. Substitution reactions of the aromatic series.
2. Halogenation process. Sulfonation, nitration, nitrosation, hydroxylation.
3. Recovery, oxidation, acylation, alkylation.

Methods of teaching and learning: analysis of theoretical issues and case studies.

References:
1 Albitskaya VG, Ginsburg OF, Kolyaskina ZN, Kupin BS, LA Pavlova, Razumova NA, Rall KB, Serkova VI Stadnichuk MD Laboratory work in organic chemistry. Ed. OF Ginzburg, AA Petrov. Vysshaya. wk., 1967. - 295 p.
2 Maiofis LS Chemistry and technology of chemical and pharmaceutical products. 2nd ed., Rev. and add. - M.: Medicine, 1964. - 625 p.

Сontrol
1. What substitution reactions are used in the practice of obtaining drugs?
2. Give specific examples of the use in the synthesis of chlorinated intermediates synthesis of drugs.
3. Describe the concept of p-sulphonation?
4. What acylating agents are used in the acylation of drugs? Appreciate the nature of the acylating agents.
5.What reactions are used during the process of obtaining iodoform, phenol, benzoic acid?

APPENDIX

Lab 1 - Preparation of benzoic acid.

Toluene, 10 g
34 g of potassium permanganate
Hydrochloric acid
Round-bottom flask to 1 liter
Water cooler
Bunsen flask
Buchner funnel
Glass
Sand bath
Technique. In liter flask. Equipped with a reflux condenser, boil for 4 hours on a sand bath 10 g of toluene and 700 ml of water and 34 g of potassium permanganate melkorastertogo. For a uniform reaction mixture in boiling flask throw a few pieces of porous brick. After the reaction is colorless * solution is cooled, the precipitated manganese dioxide was filtered off and washed twice with boiling water (10-15 ml).
The filtrate was concentrated to a volume of 100-150 ml and acidified with concentrated hydrochloric acid to acid reaction to Congo. Thus precipitated benzoic acid. ITS is filtered, washed with a little cold water and dried. Mp 120-1210. Yield 70-80% of theory. [1]
[1]. Albitskaya VG, Ginsburg OF, Kolyaskina ZN, Kupin BS, LA Pavlova, Razumova NA, Rall KB, Serkova VI Stadnichuk M . D. Laboratory work in organic chemistry. Ed. OF Ginzburg, AA Petrov. Vysshaya. wk., 1967. - With. 139.

* If the reaction mixture remains colored, bleaching achieved by adding a few drops of alcohol.

Oxidation reaction used to produce oxygen-containing compounds. The oxidation can be carried out by atmospheric oxygen and various oxidants. The most commonly used organic oxidizer is potassium permanganate oxidation power of which depends on the medium. Used for the oxidation of aqueous solutions of different concentrations of potassium permanganate in neutral, acidic or alkaline media.

* Lab 2 - Using the halogenation reaction when receiving iodoform.

Iodoform - crystalline solid lemon yellow with a foul odor. Threshold of feeling the smell 0,000006-0,00027 mg / l, volatile with steam. The melting point of 116-120 0, specific gravity 4.003. In ethanol at 17-18 0 iodoform dissolved 1:75 and 1:10 in the air. It is soluble in acetone, a little - in petrol.
Iodoform production of acetone is reduced to two chemical steps of: obtaining a solution of sodium hypochlorite and getting iodoform using transactions settling, separation, decantation, centrifugation, washing with water, alcohol and drying.
1. Chlorinator stainless steel or enameled. Best of antihlor or monelmetalla equipped with a stirrer, bubbler and a jacket filled with 30% sodium hydroxide solution. Chlorinators can be joined together. On the first pass of the chlorine gas cylinder through the bubbler, and the second is the absorber unabsorbed chlorine. The process is to produce heat. The unit is cooled, preventing the temperature rise above 30 0. At the end of the first chlorination apparatus chlorine is passed in the second and the first is used as an absorber, filling it previously sodium hydroxide. The resulting solution of sodium hypochlorite was adjusted with water to a specific gravity 1,21-1,27.
2. Getting iodoform are in the unit, stainless steel, equipped with cooled brine. There with a solution of sodium hypochlorite and acetone, and from the measuring device to pre-load solution of sodium or potassium iodide. At the beginning of an intense yellow-brown color, which can be observed with an excess of sodium hypochlorite. This is due to the liberation of free iodine, which is totally undesirable, since it leads to the generation, besides iodoform and iodate (passing later in the mother liquor, reducing the output of iodoform and lead to the overhead of expensive sodium iodide).
Recommended that a loading of reactants as follows. Hypochlorite and acetone into the reactor uniformly and at the same time, and the process is conducted with careful stirring and cooling apparatus brine. The reaction temperature should not exceed 10 0. All the while watching the reaction mixture and controls the supply of solutions so that paint was intensely yellow, not brown.
To determine the end of the reaction in the filtrate of the reaction mixture, poured into two test tubes, add: one tube 10-15 drops of a solution of sodium hypochlorite, and in another - 3-5 drops of acetone. If nevypadeniya precipitate iodoform in both tubes reaction was considered complete. This test was repeated in an hour, and then after 30 minutes settling sifoniruyut liquor through a cloth and let down and drains. Technical iodoform after settling, separation and decantation suck in a special decanter - the unit with a mixer, where washed 3-4 times with purified water, and then - with a solution of hydrochloric acid to remove the calcium and iron, and then again washed with purified water and transfer to a centrifuge, where again washed with water, then alcohol. Moist iodoform dried on trays in an oven at 50 kalorifernoy 0. The dry product is screened for elektrovibratsionnom sieve. Packed product in banks orange glass. Screenings are subjected to grinding in a porcelain ball mill [2].
[2]. Maiofis LS Chemistry and technology of chemical and pharmaceutical products. 2nd ed., Rev. and add. - M.: Medicine, 1964. - With. 221-223.

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