Publikace detail

The influence of residue sodium ions in mixed oxide on catalytic activity in transesterification of vegetable oil

Autoři: Kocián David | Hájek Martin | Vávra Aleš | Frolich Karel | Kocik Jaroslav

Rok: 2022

Druh publikace: článek v odborném periodiku

Název zdroje: Molecular Catalysis

Název nakladatele: Elsevier Science BV

Místo vydání: Amsterdam

Strana od-do: "112017-1"-"112017-10"

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
cze	Vliv zbytkových sodíkových iontů ve směsných oxidech na katalytickou aktivitu v transesterifikaci roztlinných olejů	Vliv zbytkového obsahu sodíkových iontů (v množství 5-345 mikro-mol/g hydrotalcitu) na katalytickou aktivitu směsných oxidů byl testován pro transesterifikaci rostlinných olejů. Detailně je popsán proces transformace sodíkových částic během syntézy směsného oxidu, vliv na reakci s vodou, typ katalýzy a výtěžek.	hydrotalcity; směsné oxidy; transesterifikace; sodné ionty; metyl estery
eng	The influence of residue sodium ions in mixed oxide on catalytic activity in transesterification of vegetable oil	The Mg-Al mixed oxides are an attractive acid-base catalyst with various activity published even for the same reaction under similar conditions. The differences in the results can be caused by impurities remaining after synthesis, which is very often omitted in papers. The influence of remaining sodium impurities (from 5 to 345 mu mol/g of hydrotalcite) on the catalysed transesterification of vegetable oil was studied. The novelty consists in the detailed description of the transformation of sodium species throughout synthesis of mixed oxides: the sodium nitrates, presented in hydrotalcites, were transformed to sodium oxide (during calcination), which reacted with water (present in oil and methanol) to sodium hydroxides. During transesterification, the sodium hydroxide leached to the liquid phase and so increased the ester yield as a homogeneous catalyst. The ester content was only 19 wt.% with the catalyst containing almost no sodium ions (5 mu mol/g), but only 18 mu mol/g caused increasing of ester content to 50 wt.%. Moreover, the sodium compounds rapidly increased the catalyst activity by changing the active sites. The reusability of the catalyst was caried out and the ester content decreased to only 22% after four cycles, because the sodium leached.	hydrotalcites; mixed oxides; transesterification; sodium ions; methyl esters

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