摘要:
The present invention relates to a continuous process for preparing levulinic acid from starch in a reactive extrusion process. In a preferred embodiment, the extrusion takes place in a twin-screw extruder having a plurality of temperature zones wherein the starch slurry is preconditioned, extruded, filter pressed, reboiled, vacuum distilled, condensed, centrifuged, whereby the waste effluent from the centrifugation is reprocessed upstream to the preconditioning stage.
摘要:
To prepare a biodegradable plastic, biodegradable materials such as starches and a non-biodegradable polymer such as a polystyrene, polyurethane, polyethylene, polypropylene, or polycarbonate are treated: (1) under heat, pressure and reagents to break the polymers; and (2) by adding to them an oxidizing agent. This treatment forms and/or makes available reactive groups for bonding: (1) on the biodegradable material groups such as aldehyde or hydroxyl groups in the case of the carbohydrates and amine groups in the case of proteins and certain other compounds such as urea; and (2) on the non-biodegradable plastic groups such as aldehydes, methyl, propyl, ethyl, benzyl or hyroxyl groups. In one embodiment, plastic and starch are processed in an extruder by: (1) mixing a starch in a range of between 15 percent and 80 percent, an oxidizing agent and an agent to break up the starch and the plastics; and (2) subjecting the combination to sufficient heat and/or pressure to break the plastic into shorter chains and bond monosaccharides to monomers from the non-biodegradable polymer.