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The conversion uses N 2 O 4 and nitric acid at 5–10 °C in the liquid phase. After esterification and dehydration MMA is obtained. Challenges with this route, aside from yield, involve the handling of large amounts of nitric acid and NO x. This method was discontinued in 1965 after an explosion at an operation plant. [10]
Epoxide monomers may be cross linked with themselves, or with the addition of a co-reactant, to form epoxy; BPA is the monomer precursor for polycarbonate; Terephthalic acid is a comonomer that, with ethylene glycol, forms polyethylene terephthalate. Dimethylsilicon dichloride is a monomer that, upon hydrolysis, gives polydimethylsiloxane.
Methylmalonic acid is a by-product of the propionate metabolism pathway. [2] The starting sources for this are the following with the respective approximate contributions to whole body propionate metabolism in brackets: [3] essential amino acids: methionine, valine, threonine and isoleucine [4] (~ 50%) [3] odd-chain fatty acids [4] (~ 30%) [3]
The simple summary is that DNA makes RNA, and then RNA makes proteins. DNA, RNA, and proteins all consist of a repeating structure of related building blocks (nucleotides in the case of DNA and RNA, amino acids in the case of proteins). In general, they are all unbranched polymers, and so can be represented in the form of a string.
The units were joined by condensation of the carboxylic acid group –C(=O)OH of one monomer with the amine group H 2 N− of the next one. Some biologically important oligomers are macromolecules like proteins or nucleic acids; for instance, hemoglobin is a protein tetramer. An oligomer of amino acids is called an oligopeptide or just a peptide.
Methacrylic acid undergoes several reactions characteristic of α,β-unsaturated acids (see acrylic acid). These reactions include the Diels–Alder reaction and Michael additions . Esterifications are brought about by acid-catalyzed condensations with alcohols, alkylations with certain alkenes, and transesterifications.
Larger structures such as nucleic acids and proteins, and many polysaccharides are not small molecules, although their constituent monomers (ribo- or deoxyribonucleotides, amino acids, and monosaccharides, respectively) are often considered small molecules.
Protein structure is the three-dimensional arrangement of atoms in an amino acid-chain molecule. Proteins are polymers – specifically polypeptides – formed from sequences of amino acids, which are the monomers of the polymer. A single amino acid monomer may also be called a residue, which indicates a