NAPHTHALENEDISULPHONIC ACID FORMATION WITH 20-PERCENT OLEUM

Many authors have described naphthalene disulphonic acid formation by sulphonation of naphthalene with sulphuric acid: the proportions of th e different isomers in this reaction are discussed under several sets of experimental conditions, On the contrary, little data is available concerning the use of oleum as a sulphonation medium, The use of oleum as a sulphonating medium is interesting from an industrial point of v iew for monosulphonic acid preparation, since it results in fast react ion rates and yields a minimum of water, However, since polysulphonic acid formation is enhanced in this way, it is important to know how mu ch of these unwanted products are formed. The proportion of the differ ent isomers of the obtained naphthalenedisulphonic acids is strongly d ependent on reaction conditions, This work deals with the influence of reaction time and temperature on the reaction yields, HPLC is used fo r diacid separation and determination.