Barium Sulfate Crystallization in the Presence of Variable Chain Length Aminomethylenetetraphosphonates and Cations (Na+ or Zn2+)

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• 作者：Eleni Barouda ; Konstantinos D. Demadis ; Sandra R. Freeman ; Franca Jones ; Mark I. Ogden
• 刊名：Crystal Growth & Design
• 出版年：2007
• 出版时间：February 2007
• 年：2007
• 卷：7
• 期：2
• 页码：321 - 327
• 全文大小：567K
• 年卷期：v.7,no.2(February 2007)
• ISSN：1528-7505

文摘

Barium sulfate is a common scale in oil production installations that is treated and controlled with phosphonateinhibitors. A fundamental understanding of how these inhibitors operate, however, is only slowly emerging. In this paper, we investigatethe effect on barium sulfate crystallization of two very similar phosphonate molecules that only differ in their backbone spacing,ethylenediamine-N,N,N',N'-tetra(methylenephosphonic acid) (EDTMP) and hexamethylenediamine-N,N,N',N'-tetra(methylenephosphonic acid) (HDTMP). It was found that the inhibitory efficacy of the organic molecules depends on their structural differences butalso on the presence of other cations such as Zn²⁺. It appears that both stereochemical considerations and complexation strengthdifferences between the two phosphonate additives result in different inhibitory powers. In the presence of zinc cations and EDTMP,it is found that inhibition is related to the concentration of uncomplexed ("free") organic.