Page 12 - Microsoft Word - Sulfo and Sulfa 1.doc

Chlorosulfonic Acid Sulfation Equipment

Chlorosulfuric acid can be used to sulfonate in either a batch or continuous process. For
the batch process, illustrated in Figure 12, the equipment is a glass lined, stirred, sealed
reactor with heating and cooling jackets. The reactor must be fitted with a glass lined
absorber to remove the HCl gas evolved in the reaction. A slight vacuum is usually
pulled on the reaction vessel to enhance HCl removal. The liberated HCl gas is absorbed
into water to make a dilute HCl solution. In operation, the alcohol or ethoxy alcohol
feedstock is charged to the reactor and chlorosulfuric acid is gradually added. A good
refrigeration system is required for heat removal because the reaction is exothermic. The
reaction mass must be kept at approximately 25°C to avoid side reactions and color body
formation and to minimize foaming. The rate of addition of chlorosulfuric acid is
adjusted to ensure that this temperature is not exceeded. Immediate neutralization is
required once the reaction is complete.

Figure 12. Batch Chlorosulfonic Acid Sulfation

Water Vacuum

HCl
Absorber

Dilute
HCl
Solution

Chlorosulfonic Alcohol or
Acid Ethoxy Alcohol
Refrigerated
Cooling

Product
Load Cell

Chlorosulfation can also be continuous. Figure 13 shows a typical flow sheet for a
continuous chlorosulfuric acid sulfation process. In this application the alcohol and
chlorosulfuric acid are added into a mixing zone, combined and sent to a degasser. A
slight vacuum is pulled on the degasser to assist separation of HCl from the reaction
products. The disengaged sulfonic acid is sent through a heat exchanger to remove the
heat of reaction and recycled back to the mixer to cool the process. A portion of the

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