Abstract: Diphenyl phthalates are purified by crystallizing them from dipolar-aprotic solvents or solutions of solvents containing such solvents. The phthalate solutions are advantageously, but not necessarily, treated in a carbon column in hydrocarbon solvent without dipolar-aprotic solvents present to remove part of the color and impurities, and then dipolar-aprotic solvents are added to the solution before crystallization to aid in the final removal of color and impurities.

Abstract: Disclosed herein is an assembly for forming a radial end flange upon a length of spirally wound corrugated metal pipe. The assembly includes a head stock having a pair of rotatably driven flanging rollers for preparing the end of the pipe to be flanged and initiating the flange, an ironing wheel mounted perpendicularly with respect to the flanging rollers for completing the flange, and a shearing wheel associated with one of the flanging rollers for removing excess metal from the formed end flange. The assembly also includes a tail stock having upper and lower support rollers for securely supporting the other end of the pipe and a center turntable support for positioning the length of pipe to be flanged.