Summ

Thank you very much!!

I understand what solutions I have to make and how to conduct the experiment. It is also clear for me the diazotization at the first step but I cannot understand the reaction mechanism of the azo coupling with these reagents.

I found another paper with the same procedure. https://www.jstage.jst.go.jp/article/jos/59/3/59_3_151/_pdf " 2.3.1 Synthesis of intermediate (3) To a mixture of p -aminophenol (2.0 g, 18.3 mmol) in 20 ml of water, 3 mM HCl aqueous solution (30.3 ml) was added dropwise over 30 min at rt; an aqueous solution (108 mL) of NaNO 2 (1.3 g, 18.8 mmol) was then slowly added over 120 min at 0°C . The reaction mixture was added dropwise to an aqueous solution consisting of water (18.3 mL), CuSO4･5H2O (8.2 g, 32.8 mmol), 28% NH 3 (5.5 mL), and hydroxyammonium chloride (1.3 g, 8.3 mmol). The reaction mixture was filtered, and the crude product was then washed with 1 M HCl. Product 3 was obtained as a yellow solid when the crude product was recrystallized from a mixed ace- tone/water solvent. The yield was 1.4 g (71%). "

For the synthesis of this diazonium salt [(HO-Benzenering-N-=-N-+)(Cl-)] they used sodium nitrite, aminophenol and HCl. I don't understand their next step. How they formed the product with the rest chemicals. I found this experimental procedure from scifinder for the synthesis of 4,4' dihydroxyazobenzene. (it's not well explained or written) In a 1 L beaker, p-aminophenol ( 18 mmol) will be added and made aqueous by adding water 20.00 ml. Then, hydrochloric acid 7 ml and water 29 ml will be added dropwise over 30 minutes. Then, 1.3 g sodium nitrite will be dissolved in water (100.00 ml, 18 mmol) and the aqueous solution of the hydrochloride will be slowly added for 2 hours. The above operations will be carried out at 0~3 °C. Into another beaker, copper(II) sulfate pentahydrate (33 mmol), ammonia water ( 29.00 mmol) and hydroxylammonium chloride ( 18 mmol) will be added, then dissolved in 18 ml water to form the diazonium salt solution. To this aqueous solution of diazonium salt, the above prepared diazotized solution will be added dropwise. Then, 18.00 ml diethyl ether will be added and coupling reaction will be carried out. After the completion of the reaction, filtered, washed with dilute hydrochloric acid solution and crude product will be obtained. Yoshino N., Kondo Y., Kawaharatsuka M., Gemini-type fluorohydrocarbon chain-introduced surfactants having azobenzene-based spacers and their preparation, Jpn. Kokai Tokkyo Koho, 2009149601, 2009 I will try to download the patent and translate it from Chinese. Thanks!!

Hi, I was wondering if anyone can help me understanding how these reactions work. What is happening by adding CuSO4-5H2O, [NH4+][OH-] and HONH2-HCl (hydroxylammonium chloride) together in an aqueous solution? Is it forming a diazonium salt solution? And when we are mixing the above solution with another diazonium salt [(HO-Benzenering-N-=-N-+)(Cl-)] in a diethyl ether solution what product are we expected to have? Will be azo coupling reaction occurred? I am trying to synthesize a dihydroxyazobenzene and I found this synthetic procedure from a patent. Any idea will be well accepted and appreciated!! Thank you in advance!