Octamethylcyclotetrasiloxane

<p>Octamethylcyclotetrasiloxane, also called D4, is an <a href="/facts/Organosilicon_compound/JvUwzDQ4">organosilicon compound</a> and one of a number of cyclic <a href="/facts/Siloxane/6fbEIal7">siloxanes</a> (cyclomethicones). It is a colorless viscous liquid with a high boiling point. It has historically been used on a large scale in <a href="/facts/Personal_care/7yPao7B0">personal care</a> products including cosmetics, hair conditioners and <a href="/facts/Emollient/wKvt6bT2">emollients</a> (moisturising creams), Global production in 1993 was 136,000 tons, however it is now facing significant pressure from regulators. It is a <a href="/facts/Substance_of_very_high_concern/SPylhVqo">substance of very high concern</a> In the EU, where it was classified as a <a href="/facts/Persistent%2c_bioaccumulative_and_toxic_substances/TJCJImvK">PBT</a> and effectively banned in personal care products in 2018. The US EPA began reevaluating its risks in 2020. Replacements include branched-chain alkanes (isoparaffins).
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Octamethylcyclotetrasiloxane open-in-new

Octamethylcyclotetrasiloxane