Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Environment

Not So Curious Flow Chemistry

June 21, 2010 | A version of this story appeared in Volume 88, Issue 25

“Firms Advance Flow Chemistry” by Michael McCoy was quite interesting, but I was surprised to learn that continuous-flow chemistry is only now “growing beyond a laboratory curiosity” (C&EN, May 24, page 10).

On the basis of my limited exposure to bulk chemical manufacturing some 50 years ago, I assumed flow chemistry was widely used today in the high-volume chemical manufacturing business. In 1959, I began my career as an analytical chemist for Ultra Chemical Co., a small specialty chemical manufacturer in Paterson, N.J., and a subsidiary of Witco Chemical Co. One of the company’s major products was sodium dodecylbenzene sulfonate, a major ingredient of the laundry detergents used in the 1960s. This material was routinely made in a 20,000-gal vessel by reacting dodecylbenzene with concentrated sulfuric acid. The resulting dodecylbenzene sulfonic acid was then neutralized with sodium hydroxide solution to form a viscous, opaque liquid termed “paste,” which was then pumped to a spray tower to create the flakes or powder for packaging.

To increase productivity, the company’s chemical engineers designed and built a pilot plant in 1961 to manufacture the material in a continuous-flow process. In that process, the reactants were separately pumped into a long stainless steel tube where the reaction took place. At the point along the tube where the sulfonation was complete, sodium hydroxide solution was introduced and the resulting “paste” pumped up to the spray tower.

I analyzed samples of the reaction mixture at various points in the flow process so chemical engineers could make adjustments to reactant flow rate and temperature to optimize yield and throughput. The pilot plant was quite successful, and I believe this process was put into full production shortly thereafter. I left the company in 1962 for graduate school and spent the balance of my career in research and development. However, since that continuous-flow process went so smoothly all those years ago, I assumed the technique had spread throughout the industry for other bulk chemical production.

Joseph A. Castellano
San Jose, Calif.

Advertisement

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.