How corrosion is controlled in making a famous Chlorinated Organic Weed-Killer When Pittsburgh Coke & Chemical Company embarked on the manufac ture of the herbicide 2,4-D some years ago, they were confronted b y some formidable corrosion and contamina tion problems. Making 2,4-D calls for the chlorination of phenol to dichlorophenol, then reacting this with monochloracetic acid to form the 2,4-D acid. Small amounts of hydrochloric acid form during chlorination, and, to gether with unreacted chlorine, con stitute a corrosion thread which per sists through the distillation stage. And beyond the fractionation stage, even small amounts of corrosion products, if allowed to form, will affect color and purity.
Pure 2,4-D is separated from underchlorinated and overchlorinated product in the solid Nickel fractionating column shown above. AU the cuts are received in nickel or Nickel-Clad Steel tanks as well, to protect product purity.
A purer, drier dichlorophe nol was the result when this Nickel still was installed at Pittsburgh Coke & Chemical ίο resist corrosion by chlo rine and hydrochloric acid.
When operations were still in the pilot plant, trouble was experienced with corrosion of certain equipment items. Inco's Corrosion Engineers wrere called in and cor rosion tests were performed at various equipment sites. As a result of the tests, nickel pipe and fittings were in stalled in the system and eventually the use of Nickel and Nickel-Clad Sieel was extended to such important items as the still, steam coils, fractionating tower, condenser and storage vessels used in making and handling di chlorophenol.
Do you h a v e a corrosion or contamination problem connected with a chlorination operation? If so, Inco Nickel or a high-nickel alloy m a y very well b e the answer. A t any rate, write to Inco's Corrosion Engineering Sec tion, stating your problem in detail. They will be glad to advise you without cost or obligation.
The tank for weighing p u r e dichlorophenol and such items as the reactor for making 2,4-D as well as stripping column, centrifuge and dryer are made of another highnickel alloy, Monel. Most of the equipment has been in successful operation for four years.
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THE INTERNATIONAL NICKEL COMPANY, 67 Wall Street
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