Polymalic acid derivatives

Polymaleic acid (PMA). The use of chemicals based on PMA and some derivatives has become standard practice for very brackish waters and seawater distillation processes around the world, where the TDS may reach 50,000 ppm TDS, or where total hardness levels exceed 500 to 1,000 ppm CaC03. Its use in RO systems is growing. However, PMA has limited dispersing properties and may need to be formulated with a dispersant chemical to provide satisfactory performance with some RO designs. It is claimed that PMA is also a successful silica deposit control agent and therefore may be incorporated into formulations where this is a problem. 

Maleate chemistry has proved to be an enduring mainstay of many water treatment formulations, primarily as non-phosphate-containing calcium carbonate scale inhibitors. For most water treatment applications, polymaleic acid and its derivatives offer a good alternative to phosphonate chemistries, when required. 

In this application oxidative degradation of a-polymalic vinyl derivatives using potassium permanganate was used to prepare higher acid homologs... 

However, it was polymaleic acid (PMA) and its derivatives, first developed in the late 1960s and early 1970s, that offered a serious challenge to the new supremacy of phosphonates. PMA proved to be a particularly effective DCA for calcium carbonate scale under high-stress conditions, and maleic acid chemistry remains a third basic organic polymer constituent of many modern cooling water treatment formulations. 

Glycosides of 5-A-acetyl-D-neuraminic acid can be synthesized using glycosyl halide derivatives with silver salts of polymeric carboxylic acids, e.g. polymaleic acid, as catalysts. 

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