Method of preparing integral generation polypropyleneimine dendrimer by reducing cyano group

Abstract

The invention discloses a method of preparing a primary amine compound by reducing a cyano group. The method is characterized in that the primary amine compound is integral generation PPI (Polypropyleneimine) dendrimer. The method comprises a step of reducing half generation PPI dendrimer in alkaline solution with sodium borohydride under normal pressure by taking Raney Ni as a catalyst under an alkaline condition, wherein the reaction is performed in the solution; the mass ratio of the Raney Ni to the half generation PPI is 1:1-7.5:1; and the molar ratio of the sodium borohydride to the cyano group in the half generation PPI is 1.5:1-4:1. The preparation method can be performed under normal pressure; and a product has the advantages of high yield and high primary amine content.

Description

technical field [0001] The invention relates to a method for preparing primary amine compounds, in particular to a method for reducing cyano groups to prepare primary amine compounds. Background technique [0002] Polypropyleneimine (PPI) dendrimers have high regularity, there are a large number of cavities inside the molecule, and there are multiple amino groups on the surface of the molecule. The unique chemical structure makes polypropyleneimine (PPI) widely used in medicinal chemistry, photosensitive materials, nano Materials and catalysis have broad application prospects. At present, the relatively mature synthesis method of PPI is to take diamine as the central core and acrylonitrile as the repeating unit, and alternately repeat the Michael addition reaction (Michael Addition, N-alkylation) and the hydrogenation reduction reaction of polynitriles to obtain Half-generation PPI (0.5G PPI, 1.5G PPI, etc.) with a cyano group at the end and an integer generation of PPI wit...

AI Technical Summary

Problems solved by technology

[0003] In the prior art, the reaction of multi-component nitriles being reduced to primary amines under the action of a catalyst needs to be carried out under high-pressure environment. For example, a prior art adopts Raney Ni to hydrogenate nitriles in alkaline solution to generate amine compounds, which has a higher Catalytic activity, but a certain amount of by-product secondary and tertiary amines are also generated in the reaction, and the reaction needs to be carried out under a higher pressure (6MPa), and the reaction time is longer (24h) (low generation polypropylene Synthesis and characterization of imine dendrimers, Fine Chemical Industry, 2001, 18(7), 414-416)

There is also a kind of reduction system (Wang Qin, Chemical Reagent, 2005, 27 (1), 8-10) that a kind of prior art is polycyano compound with Urushihara cobalt and 1,4-dioxane-water (10%) , although the yield of the reaction and the proportion of primary amines are higher, the reaction still needs to be carried out under a higher pressure (3MPa)

Another prior art uses Raney Co-Cr and water as a reducing system (Meijler, Angew.Chem.Int.Ed.Engl., 1993, 32:1306-1308), successfully realizing the conversion of polyvalent nitriles to primary amines , the product does not need to be separated, and the yield of primary amine

Images