An efficient method for converting glucose into 5-hydroxymethylfurfural (5-HMF), in the presence of CrCl3 catalyst, is developed by using the ionic liquid 1-butyl-3-methyl imidazolium chloride as solvent. A 5-HMF yield of 71 % is achieved in 30 s for 96 % glucose conversion with microwave heating at 140 °C. The activation energy of glucose conversion is determined to be 114.6 kJ mol−1, with a pre-exponential factor of 3.5×1014 min−1. Fructose, sucrose, cellobiose, and cellulose are studied and 5-HMF yields of 54 % are obtained for cellulose conversion at 150 °C during 10 min of reaction time. Recycling of the ionic liquid and CrCl3 is demonstrated with six cycles of use.