Low-Temperature and Low-Pressure Reaction for Unit Operations Laboratory Experiment

We developed a Standard Operating Procedure (SOP) for the packed bed reactor at Rose-Hulman Institute of Technology for use in the Unit Operations Laboratory courses. Multiple reactions that would be possible under the conditions of the reactor were researched and then tested in the reactor. The limits of the reactor were temperatures less than 100ºC and pressures less than 100 psig, with the reaction also being safe for undergraduate use. After testing the reactions and gathering example data, an SOP for that reaction and a project brief for faculty use was created. The first reaction that was tested was the combination of acetone and glycerol in an ethanol solvent while the reactor was packed with Amberlyst-15 acidic ion exchange resin to produce Solketal. The results from this reaction provided an average of 26% yield of the product with less than 2% deviation. Reaction conditions were changed to determine effects on conversion and yield. These tests resulted in expected trends based on reaction fundamentals and literature.^1,2 The second reaction that was tested was the dehydration of fructose over the same Amberlyst-15 catalyst to produce 5-hydroxymethylfurfural. The baseline results found were an average of 7.64% yield of 5-HMF product with a 2.01% deviation, while the average fructose conversion was 23.74% with a 3.76% deviation. To test the variability of this reaction, we changed two different points, the flowrate and the concentration of fructose. Testing the lower flowrate, we found that it converted nearly all of the fructose, but only produced a 5.50% yield of product. The results from increasing the concentration of fructose gave a lower yield of product, but overall, it produced slightly more moles than the original concentration experiments. One setback of this reaction with our setup is the temperature requirements. Our reactor uses a water bath heater, so we are unable to exceed 100ºC. Due to heat loss across the reactor and tubing, the reactor struggled to reach 80ºC, which hindered the conversion of fructose into the product. Another cause for the low yield of the product is its rehydration into levulinic acid and formic acid. We were able to realize the potential of Amberlyst-15 as a catalyst in the liquid-phase packed bed reactor for multiple reactions. These reactions were verified to meet the needs for the Unit Operations Laboratory.

References

1. Corrêa, Isabella, et al. “Continuous valorization of glycerol into solketal: From the fixed-bed adsorptive reactor to the simulated moving-bed reactor.” Industrial & Engineering Chemistry Research, vol. 61, no. 11, 11 Mar. 2022, pp. 4017–4030, https://doi.org/10.1021/acs.iecr.1c04832.
2. Moreira, Miguel N., et al. “Solketal production from glycerol ketalization with acetone: Catalyst selection and thermodynamic and kinetic reaction study.” Industrial & Engineering Chemistry Research, vol. 58, no. 38, 5 Sept. 2019, pp. 17746–17759, https://doi.org/10.1021/acs.iecr.9b03725.