Fig. 3(E) plots the effects of reaction temperature and time
on 5-HMF formation. At low temperatures, which are to say,
until 120 C, the 5-HMF yield linearly increased, and at 130 C,
it was consistently maintained after 2 h. At 140 C, the 5-HMF
concentration slightly decreased with passing reaction time; at
the same temperature after 2 and 3 h, it was lower than at
130 C. These results indicated that the 5-HMF produced from
the sugars had been further converted into LA and formic acid
by hydration