Study On The Synthesis Aromatic Aldehyde

In the synthesis of aromatic aldehydes, we usually synthetic aromatic aldehydeunder the situation that benzene ring has already had other group that takes effect onthe activity of benzene ring and synthetic aromatic aldehyde. In this paper, I inquireinto the impact of nitro-group, hydroxyl and carboxyl on the synthetic aromaticaldehyde.First, this paper，considering the requirements of environmental protection,economic and social value of the case， compares the method of synthesis of2-hydroxy-5-nitro-benzaldhyde. At last, this paper synthetics2-hydroxy-5-nitro-benzaldhyde by the Duff reaction and optimizes the conditions ofthe various effects involved in the reaction. The optimum conditions were as follows：the amount of the p-nirothenol2.78g, hexamethylenetetramine5.6g, solid catalyst0.4g，glacial acetic acid15mL, acetic anhydride8mL, the temperature being about90℃and the reaction time about3h. The product was determined by infraredspectroscopy and LC.Second, the synthesis of3-carboxy-4-hydroxybenzoic acid is born on thesynthetic of2-hydroxy-5-nitro-benzaldhyde. This paper optimizes the conditions ofthe various effects involved in the synthesis of3-carboxy-4-hydroxybenzoic acidreaction. The optimum condition were as follows：the amount of the4-hydroxbenzoicacid2.78g, solid catalyst0.3g, hexamethylenetetramine5.6g, glacial acetic acid15mL,acetic anhydride8mL, the temperature being about90℃and the reaction time about3h. The product was determined by LC, infrared spectroscopy and HNMR. Thesynthesis of3-carboxy-4-hydroxybenzoic acid proved that this synthesis method inthe synthesis of a single aldehyde aromatic aldehyde is certain universality.Third, the synthesis of2-Hydroxy-5-Caroxylisophthalaldehyde adopts the waythat is used in synthesis3-carboxy-4-hydroxybenzoic acid and2-hydroxy-5-nitro-benzaldhyde. This paper optimizes the conditions of the variouseffects involved in the synthesis of2-hydroxy-5-nitro-benzaldhyde reaction. Theoptimum condition were as follows：the amount of the4-hydroxbenzoic acid2.76g,hexamethylenetetramine5.6g, solid catalyst0.8g, glacial acetic acid15mL, aceticanhydride8mL, the temperature about90℃and the reaction time about3h. Theproduct was determined by LC-MS and infrared spectroscopy. This synthesis methodis not only certain universality in the synthesis of a single aldehyde aromatic aldehyde,but also feasible in the synthesis of double aldehyde aromatic aldehydes. after the synthesis of2-Hydroxy-5-Caroxylisophthalaldehyde.There are some innovations in this paper: First, this thesis uses a solid catalyst inthe synthesis of aromatic aldehydes in the duff reaction. Second, double aromaticaldehyde aldehydes synthesis by the improvement of the Duff reaction, breaks therestrictions that Traditional Duff reaction can only be synthesized single aldehyde andaromatic aldehydes and greatly expands the scope of application of the Duff reaction.