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Very fast H 2 production from the methanolysis of NaBH 4 by metal‐free poly(ethylene imine) microgel catalysts
Author(s) -
Sahiner Nurettin,
Demirci Sahin
Publication year - 2017
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.3679
Subject(s) - catalysis , chemistry , protonation , sodium borohydride , polymer chemistry , nuclear chemistry , inorganic chemistry , organic chemistry , ion
Summary The polyethyleneimine (PEI) microgels prepared via microemulsion polymerization are protonated by hydrochloric acid treatment (p‐PEI) and quaternized (q‐PEI) via modification reaction with methyl iodide and with bromo alkanes of different alkyl chain lengths such as 1‐bromoethane, 1‐bromobutane, 1‐bromohexane, and 1‐bromooctane. The bare p‐PEI and q‐PEI microgels are used as catalysts directly without any metal nanoparticles for the methanolysis reaction of sodium borohydride (NaBH 4 ). Various parameters such as the protonation/quaternization reaction on PEI microgels, the amount of catalyst, the amount of NaBH 4 , and temperature are investigated for their effects on the hydrogen (H 2 ) production rate. The reaction of self‐methanolysis of NaBH 4 finishes in about 32.5 min, whereas the bare PEI microgel as catalyst finishes the methanolysis of NaBH 4 in 22 min. Surprisingly, it is found that when the protonated PEI microgels are used as catalyst, the same methanolysis of NaBH 4 is finished in 1.5 min. The highest H 2 generation rate value is observed for protonated PEI microgels (10 mg) with 8013 mL of H 2 /(g of catalyst.min) for the methanolysis of NaBH 4 . Moreover, activation parameters are also calculated with activation energy value of 23.7 kJ/mol, enthalpy 20.9 kJ/mol, and entropy −158 J/K.mol. Copyright © 2016 John Wiley & Sons, Ltd.