Конверсія D-фруктози в етиллактат на SnO2-вмісних каталізаторах
The study is directed to the search of effective catalysts for ethyl lactate obtaining from fructose as renewable raw material. A series of SnO2-containing oxides for transformation of 13 % fructose solution in 98 % ethanol was prepared by impregnation of different carriers. The reaction was carried...
Збережено в:
| Дата: | 2019 |
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| Автори: | , , |
| Формат: | Стаття |
| Мова: | Ukrainian |
| Опубліковано: |
Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine
2019
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| Теми: | |
| Онлайн доступ: | https://www.cpts.com.ua/index.php/cpts/article/view/495 |
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| Назва журналу: | Chemistry, Physics and Technology of Surface |
Репозитарії
Chemistry, Physics and Technology of Surface| Резюме: | The study is directed to the search of effective catalysts for ethyl lactate obtaining from fructose as renewable raw material. A series of SnO2-containing oxides for transformation of 13 % fructose solution in 98 % ethanol was prepared by impregnation of different carriers. The reaction was carried out in autoclaves while rotating at a speed of 60 rpm for 3 h at 160 °C. The products of fructose conversion were analyzed using 13C NMR spectroscopy. The textural characteristics, strength and concentration of acid and base sites of the synthesized mixed oxides are given. All samples are characterized by a developed surface – 90–380 m2/g, a sufficiently large pore volume – 0.5–0.95 cm3/g, and a wide distribution of pores diameter – 10–20 nm. It has been shown that the acidic oxides SnO2 and SnO2/SiO2 dehydrate fructose to 5-hydroxymethylfurfural, levulinic and formic acids and their esters. The basic SnO2/MgO-ZrO2 mixed oxide promotes the conversion of fructose towards the formation of 1-hydroxy-2-butanones, hydroxyacetone, ethyl propionate and ethyl formate. SnO2/ZrO2-TiO2 samples catalyze the dehydration of fructose to 5-hydroxymethyl furfural with 77-90 % selectivity. The addition of SnO2 to Al2O3 leads to a significant increase in the yield of the target product - ethyl lactate. Thus, the 20SnO2/Al2O3 catalyst provides 97 % fructose conversion with a 49 % yield of ethyl lactate. It has been found that the addition of zinc ions to SnO2/Al2O3 leads to the formation on the surface of a mixed oxide of a weak basic sites with H0max =+7.2. Thus on 10SnO2-5ZnO/Al2O3 catalyst the selectivity of ethyl lactate formation increases to 56 % at 100 % fructose conversion. The schemes for fructose conversion to ethyl lactate at acid L-centers of Sn 4+ are discussed. The obtained results show that namely acid IVSn4+ L-sites catalyze aldol decondensation of fructose as the first stage of the ethyl lactate formation as well as initiate the isomerization of hemiacetal into ethyl lactate. |
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