Microcrystalline cellulose equation

Figure 4 also shows the excellent fit to the GAB equation (Eq. 10) of the sorption and desorption isotherms for microcrystalline cellulose. In this regard, this equation offers considerable practical utility in fitting isotherms for these types of materials over the entire relative humidity range, especially in contrast to the BET equation, which usually only fits uptake data up to about 40% relative humidity. As we have mentioned, however, this does not in itself confirm the validity of the GAB model for describing moisture sorption data on these materials. Rather, independent confirmation of the physical meaning is necessary. 

Moisture sorption of microcrystalline cellulose has been studied extensively. Fig. 6A includes the sorption and desorption studies for microcrystalline cellulose. The inserts are plots of moisture content versus time, which approximately represent the kinetics of sorption and desorption at each humidity. The equilibrium adsorption isotherm (Type II) has been fit to the BET equation (C = 16.48, = 0.033 g/g solid) and this curve is... 

Fig. 6 (A) Moisture sorption isotherm for microcrystalline cellulose adsorption and desorption. (Adapted from Ref (B) BET and GAB equations describing the adsorption branch.

A number of tetraorganotin (though not yet tetraalkyltin) compounds in which the chirality is centred on the tetrahedral tin centre have been optically resolved by either (a) recrystallisation of the diastereoisomers which are formed with an optically active reagent (e.g. equation 5-1 and 5-2), or (b) by an asymmetric synthesis (e.g. equation 5-3), or (c) by chromatography on microcrystalline cellulose acetate (e.g. equation 5-4).2 These compounds are listed in Table 5-2, where the group which is involved in an asymmetric synthesis is printed in italics. In only a few cases is the optical purity known. 

Zeronian and co-workers (3) proposed that a better estimate of the fraction of amorphous material (F) in a cellulose sample can be obtained from its moisture regain (M ) if the moisture regain of the microcrystalline cellulose produced from hydrolysis (M ) and the moisture regain of amorphous cellulose (M ) are taken inEo consideration iy using equation The preparation of the microcrystalline cellulose is critical in order for it to be used as a reasonable facsimile of the crystalline regions present in the fiber (3). 

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