Study On Synthesis And Wood Decay-resistant Characteristics Of Hexaconazole’s Derivatives

Organic wood preservatives can be selected from pesticides. Triazoles, as a kind of pesticides, had good inhibition effects on the fungi of basidiomycetes and ascomycetes with characteristics of broad spectrum, high and long-acting efficiency, low toxicity to humans and animals. Triazoles were being used as wood preservatives. But triazoles had no broad spectrum or long-term effects as wood preservatives which limited the development of them. In order to improve bactericidal characteristics and long-term effects, hexaconazole was chemically modified referring to the relationship between chemical structures and bactericidal activities.Eight compounds were synthesized based on the chemical structures of hexaconazole. The performences of those compounds were selected and evaluated by antimicrobial activities test,anti-mould, anti-decay and leaching resistance experiments compared with tebuconazle and hexaconazole. The main researches and conclusions were summarized as follows.1. Hexaconazole was synthesized by Friedel-Crafts acylation, Corey-Chaykovsky reaction and 1,2-epoxide opening reaction with raw materials of valeryl chloride and 1,3-dichlorobenzene.To improve bactericidal effects of hexaconazole, eight compounds were synthesized according to the synthesis conditions of hexaconazole. They were modified by keeping active group of1,2,4-triazole and changing substituent groups of benzene and n-butyl group. The groups of fluorobenzol, chlorobenzol, methylbenzol and isobutyl were introduced to the compounds. These compounds were confirmed by MS and1H-NMR. All of them were stable and had no obvious changes in appearance for a long time.2. Wood-rotting fungi such as white-rot fungi(Coriolus versicolor, Irpex lacteus),brown-rot fungi(Gloeophyllum trabeum, Postia placenta) and mould(Aspergillus niger,Trichoderma viride) were used to test the antimicrobial activities of these compounds by agar-well diffusion method. The results showed that antimicrobial activities increased with the solution concentration in the concentration( mass fraction) range of 0.5 %~2.0 %. Antimicrobial activities of hexaconazole on wood-rotting fungus were superior to tebuconazle and were less than tebuconazle on mould. Compared with hexaconazole and tebuconazle, the overall antimicrobial activities of compounds C2 and C3 were better than hexaconazole and tebuconazle.Antimicrobial activities of compound C3 were the best, and compound C2 was followed by C3.Antimicrobial effects of compounds A1, A2, A3 and C1 were not as good as hexaconazole and tebuconazle. Compounds A4 and A5 had little inhibitory activities on wood-rotting and mould fungi. The conclusions were that introductions of isobutyl group in tertiary alcohol carbon,2,4-dichlorophenyl and 2,4-difluorophenyl were conducive to increasing antimicrobial activities of compounds.3. Anti-mould effects of target compounds except compounds A4 and A5 were tested andtheir performances were compared with hexaconazole and tebuconazle. The results showed that anti-mould performances were increased with the solution concentration in the range of0.1 %~1.5 %. Anti-mould performances of tebuconazle on Aspergillus niger were equal to hexaconazole and a little better than hexaconazole on Trichoderma viride according to the anti-mould standard. Anti-mould grades of them on Aspergillus niger and Trichoderma viride were reached the level 0 grade in the mass fraction of 1.5 %. The overall anti-mould performances of compounds C2 and C3 were better than control compounds. Anti-mould performances of C3 on Aspergillus niger and C2 on Trichoderma viride were the best. Both of their anti-mould standards reached the level 0 grade in the mass fraction of 1.0 %. Anti-mould performances of A3 on Trichoderma viride were superior to control compounds, but were not as good as them on Aspergillus niger. Other compounds had some anti-mould effects, but all of them were less than control compounds.4. Anti-decay effects of target compounds except A4 and A5 were tested compared with hexaconazole and tebuconazle. The results indicated that antibacterial activities of compounds increased with the retention in the range of 50~500 g/m3. Anti-decay abilities of compounds A1、A2、C1 were less than hexaconazole and tebuconazle. Other compounds had good anti-decay effects. They were compared with control compounds by loss rates of wood and toxicity limits.The results showed that the order of anti-decay abilities on the four wood-rotting fungi from strong to weak successively followed by C3, hexaconazole, C2, tebuconazle, A3.5. The method of HPLC was used to test leaching resistance properties of hexaconazole,tebuconazle, A3, C2 and C3. The content detection conditions of these compounds were obtained in experiments. The results showed that leaching rates were between 10% and 21% in the retention range of 200~500 g/m3.The order of leaching resistance properties from strong to weak were C3, hexaconazole, tebuconazle,C2, A3. The lowest leaching rate was 11.92 % when the retention was 400 g/m3 of C3, while the highest was 20.94 % when the retention was 200 g/m3 of A3.