Double-step neutralisation

Ballestra double-step neutralisation system (Neutrexl (see fig. 33 ... 

For Ballestra plants running a wider range of products like alkylbenzenes, alcohols and ethoxylated alcohols, the double-step neutralisation system is recommended. This system allows neutralisation to occur in two steps 95% of the neutralisation occurs in the first loop reactor, always working under strong caustic conditions and neutralisation is cpmpleted in the compact intense mixer second step, in series with the first. This procedure may be followed for LAB-SA neutralisation. 

The double-step neutralisation system is suitable for the production of 70% SLES. Any type of organic acid in combination with any type of neutralisation agent can be used (except stoichiometric amounts of Na2C03). 

Ballestra SpA, Milano. Technical proposal for sulphur based SOj/air sulphonation/neutralisation plant with a multitube FFR sulphonation reactor and double step neutralisation reactor. 

Molten sulpher proportioning Air drying SO2/SO3 production Film reactor sulphonation Double step neutralisation Exhaust gas treatment... 

In the first step, an SO3 molecule is implanted in the ester bond to form a mixed anhydride that exists in a very fast equilibrium with its enolic form. Then fast electrophilic addition of a second SO3 molecule occurs to the enolic double bond, and the a-sulphonated anhydride is formed. In the second (slower) step, the intermediate reacts with other fatty acid ester molecules by releasing SO3 that serve in new reaction cycles. The sulphonation goes with air-diluted SO3 at 80-90 C followed by ca. 30 min ageing at 90-95 C. The neutralisation gives rise to sodium salt of the a-sulphocarboxylic acid ester and disodium salt of the a-sulpho-carboxylic acid as a by-product. Before neutralisation, reesterification of the semifinished item has been proposed in consequence of the bad detergency of a-sulphocarboxylates. 

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