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A discontinuously operated chromatographic reactor and a reaction calorimeter were used to study experimentally and theoretically the heterogeneously catalyzed hydrolysis reactions of four esters (methyl formate, methyl acetate, ethyl formate, and ethyl acetate). Two different batches of an acidic ion-exchange resin were used as catalyst and adsorbent. The relevant distribution equilibria were quantified using pulse chromatographic experiments. The reaction rates were quantified from (a) the shape of the elution profiles and (b) the course of the heat fluxes. To this end, systematic experiments were carried out using fixed beds packed with the catalysts and a reaction calorimeter containing catalyst suspensions. Advantages and disadvantages of these two types of experimental approaches in terms of their potential to extract reliable kinetic parameters were evaluated. A simplified pseudohomogeneous model and the determined parameters were found to be capable of describing the concentration profiles in the chromatographic reactor for all reactions studied under diverse operation conditions. Copyright © 2004 American Chemical Society [accessed 2013 November 27th

The micro paddy lysimeter (MPL) was developed and evaluated for its performance to simulate solute transport in paddy environment under laboratory conditions. MPLs were constructed using soil collected from Field Museum Honmachi of Tokyo University of Agriculture and Technology, Japan. For the physical characteristics of the hardpan layer, parameters such as thickness, and soil aggregate size, affecting the percolation rate were studied. For the plow layer, two types of plow soils, sieved and un-sieved soils were compared. The sieved soil plow layer was produced by mixing air-dried soils of different aggregate sizes of D [ 9. 50, 9.50 C D [ 4.75, 4.75 C D [ 2.0 mm and D B 2.0 mm at 47.1, 19.5, 20.6, and 12.8%, respectively. The un-sieved plow layer soil was directly used after collecting from the field. Inert tracer was applied to ponding water with controlled boundary conditions to evaluate the reproducibility of the soil hydraulic characteristics. HYDRUS-1D was used to evaluate the movement of bromide tracer in the MPL. The proposed conditions of the MPL were that the hardpan layer can be made from soil aggregates smaller than 0.425 mm with 2 cm thickness and that the plow layer can be prepared with sieved or un-sieved soils. With these conditions, the obtained results proved that MPLs can be a useful tool to simulate solute transport in paddy environment.

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