Sulfonephthaleins properties

Preparation, purity, and properties of the sulfonephthaleins. The preparation of the various sulfonephthaleins from o-sulfobenzoic acid, molten zinc chloride, and a phenol (which may be halogen substituted) has been described by Clark and Lubs. A. Cohen has reported his method of obtaining xylenolsulfone-phthalein, while a number of other valuable sulfonephthaleins have become available through the work of Barnett Cohen. ... 

The properties of the most important of the sulfonephthaleins will be discussed in greater detail in the following pages. 

Aside from the sulfonephthaleins listed in the table on page 108, several others have been reported. Although they offer no practical advantage over the compounds described in detail, their properties will be summarized for the sake of completeness. 

W. C. Boyd and A. W. Rowe have described the properties of a new series of halogenated sulfonephthaleins. 

These new indicators as well as those of Clark and Lxjbs and of B. Cohen are halogenated sulfonephthaleins. Except for tetrabromo-phenoltetrabromosulfonephthalein, these compounds offer no special advantages over the indicators originally recommended. The properties of these new substances are summarized in the following table. 

Cohen, B. Synthesis and indicator properties of some new sulfonephthaleins. Pub. Health Repts. 1926, 41, 3051-3074. 

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