Arco Chemical Technology, L.p.

Beth M Steinmetz

Manish K Nandi

Robert M Arrell

A process for making crosslinked polyvinylpyrrolidone (PVP-P) is disclosed. Crosslinker generation, followed by polymerization of NVP, gives a polymer containing up to 4 wt. % of residual NVP. An aqueous mixture of the polymer is then heated in the presence of a protic acid at pH<4 to eliminate NVP. Finally, the PVP-P is neutralized with aqueous alkali metal hydroxide. The process generates a reduced volume of low-toxicity aqueous waste (<20 L/kg PVP-P) and gives PVP-P that meets important product specifications.

Process for making crosslinked polyvinylpyrrolidone

A two-step, base-catalyzed process for making crosslinked polyvinylpyrrolidone (PVP-P) having a low swell volume is disclosed. A crosslinker is generated &ldquo;in situ&rdquo; in the first step by heating a basic aqueous mixture containing a relatively low concentration of N-vinylpyrrolidone under added inert gas pressure. In a second step, the reactor temperature is reduced to initiate polymerization. The process is a productive way to make PVP-P that is easy to isolate and purify. The polymer has a swell volume less than about 40 mL H O/10 g polymer, which makes it valuable for beverage clarification.

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Bryn Mawr, PA, United States of America

Beth M Steinmetz