The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 26, 1990
Filed:
Aug. 04, 1989
Joseph R Garlich, Lake Jackson, TX (US);
Jaime Simon, Angleton, TX (US);
Tipton T Masterson, Lake Jackson, TX (US);
The Dow Chemical Company, Midland, MI (US);
Abstract
High purity ethylenediaminetetra(methylenephosphonic acid) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylenephosphonic acid) are prepared by dissolving the aminomethylenephosphonic acid in an aqueous base, acidifying with a mineral acid at an elevated temperature to precipitate the crystals, maintaining the solution at an elevated temperature for a period of time sufficient to assure crystallization, cooling to a lower temperature and maintaining at that temperature for a time sufficient to precipitate the crystals and filtering the resulting crystals at that temperature, washing the crystals with water and recovering the desired high purity aminophosphonic acid. The ethylenediaminetetra(methylenephosphonic acid) is obtained in a purer state during its synthesis if the crystals are filtered hot without prior cooling.