Raw materials quality, storage, handling and safety

This section deals with all major aspects which require consideration when proposing to use the common raw materials found in sulphonation. 

Sulphur crystallises in at least two distinct forms, rhombic and monoclinic. Rhombic sulphur, SA, is stable at atmospheric pressure up to 95.5at which temperature transition to monoclinic sulphur, SB, can take place. Monoclinic sulphur is stable up to its natural melting point of 114.5 0. 

The molecular constitution of liquid sulphur undergoes significant and reversible changes with increasing temperature, as evidenced by the characteristic temperature dependance of physical properties, notably viscosity. The sudden increase in sulphur viscosity above 159 0 is attributed to the formation of polymeric sulphur molecules, (see 3.1.4 and figure 3.) 

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