Color rendering factor

One important factor to consider in the preparation of the organic phase is the presence of inhibitors in the monomers. Some formulae call for the removal of inhibitors, primarily TCB, from the monomers. The TCB inhibitor forms highly colored complexes with metallic salts rendering the final product colored. Styrene has about 50 ppm of TCB. DVB, being more reactive, contains about 1000 ppm of TCB. There are several options for the removal of inhibitors. Columns packed with DOWEX MSA-1 or DOWEX 11 ion-exchange resins (Dow Chemical Company) can be used. White drierite or activated alumina also works well. 

All sodium salts impart a characteristic yellow coloration to the Bunsen flame, the test being so delicate as to detect 3xl0-10 grams. The extreme delicacy of the test and the wide distribution of traces of sodium chloride throughout the atmosphere render the persistence or otherwise of the coloration an important factor in determining the presence or absence of sodium in the substance under examination. In the spectroscope, sodium gives a yellow line, coincident with the D-line of the solar spectrum. 

As a result of processing methods, condition of the original byproduct raw material, storage conditions, and other factors, rendered fats may have a minimum color that can be achieved by refining and bleaching. This best attainable color can be determined by the AOCS Method Cc 8d-55, refined and bleached color (tallow and greases for soaps). The various grades of rendered fats reflect different R B color values as outlined by the AFOA (14). 

Because of ligand-field factors, certain transition metal ions, notably Cr + and Co +, almost exclusively exhibit a coordination number of six in their complexes. The kinetically inert nature of Cr and Co complexes, dramatically different from that of the extremely labile lanthanide solvento ions, facilitates the isolation of isomeric species and was crucial in enabling Alfred Werner to formulate the fundamental tenets of coordination chemistry. For simple lanthanide ion complexes, their lability and the lack of a marked sensitivity of their visually observed colors to the nature of the coordination sphere renders Wernerian procedures inapplicable, such that the establishment of high and variable coordination numbers as a characteristic of lanthanide ions has depended largely on modem spectroscopic and crystallographic measurements. 

Beef tallow is the main t. used. There are other types, such as mutton t. (- tallow (mutton), which is used only industrially and has similar properties as beef tallow. Neatsfoot oil is a low-melting fat rendered from the feet of cattle it is used as - lubricant and in fat liquors (- leather auxiliaries). There are many grades and types of t., depending on the part of the animal from which it originates, the season of slaughtering, the ffa content, color, odor and many other factors. 

---