It is applied to alkylated methacrylate monomers and the initiator is a silyl ketene acetal. They are made of plastics, such as Delrin, acetal, or nylon, or sometimes aluminum. It is the dimethyl acetal of formaldehyde. Some polymers are also sensitive to attack, including acetal resin and polybutene. Instead it is handled almost exclusively as its hydrate, methyl acetal, and oligomers thereof. Acetaldehyde forms a stable acetal upon reaction with ethanol under conditions that favor dehydration. Various specific carbonyl compounds have special names for their acetal forms. One of these has acetal modified hydroxyl groups. NaBAr can be used in deprotection of acetal or ketal-protected carbonyl compounds. NaBAr can also be used for deprotection of acetal or ketal-protected carbonyl compounds. For example, the carbonyl is converted into an acetal, which does not react with hydrides. The acetal is then called a protecting group for the carbonyl. Note that the acetal function (a protected carbonyl) does not react. Dioxolane is a heterocyclic acetal with the chemical formula (CH)OCH. The acetal formed from acetone is sometimes called an acetonide.