Cov yam ntxwv ntawm Raney Nickel Catalysts Hloov los ntawm Electroplating ntawm Hluav Taws Kub Kub Tubes
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Cov yam ntxwv ntawm Raney Nickel Catalysts Hloov los ntawm Electroplating ntawm Hluav Taws Kub Kub Tubes
Txawm hais tias qhov kev ua tau zoo ntawm kev hloov kho RaneyNi catalyst tau txhim kho tau zoo, nws tseem muaj cov teeb meem hauv qab no los ua ib qho catalyst rau qabzib hydrogenation rau sorbitol:
1) Cov kev xav tau siab rau cov kev mob tshwm sim: Txawm hais tias kev ua haujlwm ntawm RaneyNi catalyst tau txhim kho zoo los ntawm kev ntxiv ntau yam khoom ntxiv, ua tiav cov piam thaj hloov pauv hauv kev lag luam tseem xav tau cov tshuaj tiv thaiv siab dua, cov tshuaj tiv thaiv kub siab dua, thiab lub sijhawm tshuaj tiv thaiv ntev dua. Thaum siv hloov kho RaneyNi ua cov khoom siv hluav taws xob, cov tshuaj tiv thaiv lub zog yuav tsum siab dua 5MPa, thiab cov piam thaj hloov pauv tuaj yeem ncav cuag ntau dua 98 feem pua thaum nws siab dua 120 degree. Qhov no yuav tsum muaj kev ua haujlwm siab zoo ntawm cov tshuaj tiv thaiv hydrogenation, uas ua rau cov khoom siv nce ntxiv. Ntawm qhov tod tes, yog tias cov tshuaj tiv thaiv kub siab dhau lawm thiab lub sijhawm tshuaj tiv thaiv ntev dhau lawm, nws tuaj yeem ua rau cov khoom lag luam ntawm cov tshuaj tiv thaiv thiab txo cov kev xaiv, vim tias cov piam thaj tsis ruaj khov ntawm qhov kub thiab txias thiab muaj kev cuam tshuam isomerization. Nyob rau tib lub sijhawm, yog tias qhov kub thiab txias dhau lawm, cov reactants muaj feem xyuam rau carbonization thiab coking thaum lub sij hawm cov txheej txheem tshuaj tiv thaiv, thaiv cov pores ntawm catalyst, ua rau ib tug ntse txo nyob rau hauv catalyst kev ua si thiab deactivation. Kev ncua sij hawm ntawm cov tshuaj tiv thaiv ua rau kev ncua sij hawm isomerization, uas yuav txo qhov kev xaiv ntawm cov tshuaj tiv thaiv.
2) Kev ruaj ntseg ntawm cov catalyst tsis zoo: Cov kua qab zib aqueous qhia me ntsis acidity ntawm chav tsev kub. Raws li qhov kub nce, nws cov ionization tas li nce thiab acidity nce. Acidity muaj cov nyhuv corrosive ntawm RaneyNi catalyst, ua rau cov khoom siv nickel thiab additives yaj nyob rau hauv ib tug loj npaum li cas ntawm cov tshuaj tiv thaiv kab mob thiab poob, yog li txo cov catalyst cov dej num thiab ua rau lub nra ntawm cov khoom refining kho, cuam tshuam cov khoom zoo. . Yog li, thaum RaneyNi siv los ua cov piam thaj hydrogenation catalyst, cov kev ua haujlwm catalytic ntawm cov tshuaj tiv thaiv yog qhov zoo ntawm pH 8-9. Txawm li cas los xij, nyob rau hauv cov xwm txheej alkaline, cov piam thaj tsis ruaj khov, thiab txawm tias nyob hauv chav tsev kub, cov tshuaj isomerization tseem ceeb tuaj yeem tshwm sim los tsim fructose, mannose, thiab mannitol [14,15], cuam tshuam rau kev xaiv cov piam thaj hydrogenation. Yog li ntawd, thaum siv hloov kho RaneyNi raws li ib tug catalyst, nws yog ib qho tseem ceeb uas yuav tau xaiv ib tug haum pH kom ntev lub catalyst lub neej thaum txo isomerization tshwm sim. Noj rau hauv tus account pH ntawm cov tshuaj tiv thaiv kab mob rau cov piam thaj hydrogenation los tsim sorbitol, nws raug nquahu kom xaiv pH ntawm 7-8. Qhov zoo ntawm hom catalyst no yog tias nws pheej yig dua piv rau cov khoom siv hlau muaj txiaj ntsig. Yog li ntawd, nyob rau hauv cov xwm txheej uas qhov kev xav tau zoo rau sorbitol tsis nruj dhau, nws yog tam sim no xav siv pheej yig hloov kho RaneyNi catalysts.
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