Arabinose production

Figure 3 shows the results of the kinetic model constructed to represent arabinose at temperatures 135, 150, 175 and 200 oC at an acid concentration of 2.5% w/ w. The model was constructed through calculating best fit reaction coefficients for k1 and k2.

From observing these graphs it can be seen that the models generated for arabinose production at 2.5% w/w acid concentration are highly accurate. Along with the model for the reaction the experimental values against the model values are constructed to test that the data fits. The correlations represented by R2 are seen to be well above 0.9 which indicates the high level of accuracy achieved from the model. The kinetic model is of first order principles further demonstrating that the arabinose generation reaction is a first order reaction as has been noted in numerous studies. Due to the relatively low level of arabinose being formed in this hydrolysis reaction there were a number of experiments which registered little or no arabinose formation and therefore could not be modelled accurately. These models were under operating conditions of 7.5 and 10.0% w/w acid concentration at 175 and 200oC. The reasons for these failed models are likely as a result of low concentrations formed which led to indecipherable chromatogram readings from the HPLC.

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It can be concluded that the first order models of Glucose and Arabinose, where there was reasonable experimental data, are accurate. Glucose was modelled entirely with all R2 correlations exceeding 0.95, which is acceptable. Due to discrepancies in the data points for a small number of more aggressive reactions, four models of arabinose generation where

(d.1) Arabinose model at 200oC, acid conc. 2.5% (d.2) Fitting Test

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Подпись: Fig. 3. Arabinose model with variation in reaction temperature

unachievable however the remainder attained R2 correlations exceeding 0.95. To improve the models certain data points were ignored (one or two entries per reaction) when it was judged to be upsetting the model. In all cases this improved the overall yield.

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