General chemical structure of orthophthalates. (R and R' are general placeholders.)<unk> s (, ), or<unk>  esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften polyvinyl chloride (PVC). Lower-molecular-weight<unk> s, those derived from C3-C6 alcohols, are being gradually replaced in many products in the United States, Canada, and European Union over health concerns. They are being replaced by high-molecular-weight<unk> s (those with more than six carbons in their backbone, which gives them increased permanency and durability), as well as alternative plasticizers not based on phthalic anhydride. In 2010, the market was still dominated by high-phthalate plasticizers; however, due to legal provisions and growing environmental awareness and perceptions, producers are increasingly switching to non-phthalate plasticizers. The legacy use of<unk>  plasticizers has prevented manufacturers from using post-consumer recycled PVC since that recycled content would likely contain<unk> s. Thus, many manufacturers have moved to use only virgin PVC in their products. There are, however, efforts underway to collect post-consumer PVC for chemical recycling efforts that can remove legacy<unk> s and create virgin-like PVC. Those efforts are focused on areas like healthcare where PVC makes up a significant amount of medical devices.
Phthalate
Photoanethole
Tetraethyllead
Dichloroacetic acid
Diiodohydroxyquinoline
Dicoumarol
Selenous acid
Tetrachlorodecaoxide