Abstract: With use of a relationship analyzing section for analyzing the relationship between constituent elements of a requisition sheet model described, for example, in the form of use case, and a relationship output section for outputting the analysis result to, for example, a display unit, an operator can check the presence/absence of an omission, contradiction, and the like in the displayed relationship between constituent elements, thereby easily checking whether the requisition sheet is accurately described. In addition, with use of a use case executing section for sequentially executing use cases included in a requisition sheet and a log recording section for recording a log by recording the process of executing each use case, the process of executing each use case included in the requisition sheet is recorded as a log, thereby allowing a scenario representing the operation of a system to be easily created by only sequentially executing use cases.

Abstract: A process for producing isoprene is provided, which includes continuously or intermittently supplying isobutylene and/or t-butanol, formaldehyde and water into an acidic aqueous solution, and reacting the reaction mixture while distilling away a mixture containing produced isoprene, water, unreacted starting materials and other low boiling point components from this reaction mixture to the outside of the reaction system, wherein the reaction is carried out while controlling the concentration of high boiling point byproducts, which is produced and accumulated in the reaction mixture, to fall within the range of 0.5-40 mass %.

Abstract: A process for producing isoprene is provided, which includes continuously or intermittently supplying isobutylene and/or t-butanol, formaldehyde and water into an acidic aqueous solution, and reacting the reaction mixture while distilling away a mixture containing produced isoprene, water, unreacted starting materials and other low boiling point components from this reaction mixture to the outside of the reaction system, wherein the reaction is carried out while controlling the concentration of high boiling point byproducts, which is produced and accumulated in the reaction mixture, to fall within the range of 0.5-40 mass %.