Polycarbonate (functional group)

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A polycarbonate is an oxocarbon dianion consisting of a chain of carbonate units, where the successive carbonyl groups are directly linked to each other by shared additional oxygen atoms. That is, they are the conjugate bases of polycarbonic acids, the conceptual anhydrides of carbonic acid or polymers of carbon dioxide. They have the structure O[(C=O)–O]n and molecular formula [CnO2n+1]2–.

Whereas the carbonate dianion itself is well known, as found in many salts, many organic compounds containing esters of it have been made, and the parent carbonic acid is also well-known, higher homologs are substantially less stable. Only a few examples of covalent dicarbonate and tricarbonate structures and ionic dicarbonate salts have been made and their conjugate acids have only been studied theoretically. Polycarbonates up to n=6 have been studied theoretically, with the dianions being only metastable but stabilized when paired with metal counterions or as their conjugate acids. [1]

Di-tert-butyl tricarbonate extrudes carbon dioxide in the presence of various catalysts to form di-tert-butyl dicarbonate. [2] Long-chain carbon dioxide oligomers are likewise expected to decompose exothermically. [3]

Polycarbonates and their conjugate acids
Carbonate units(Poly)carbonate(Poly)carbonic acid
1

Carbonate

Carbonic acid

2

Dicarbonate

Dicarbonic acid

3

Tricarbonate

Tricarbonic acid

4

Tetracarbonate

Tetracarbonic acid

5

Pentacarbonate

Pentacarbonic acid

6

Hexacarbonate

Hexacarbonic acid

Related Research Articles

<span class="mw-page-title-main">Carbonate</span> Salt of carbonic acid

A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula CO2−3. The word carbonate may also refer to a carbonate ester, an organic compound containing the carbonate group C(=O)(O–)2.

<span class="mw-page-title-main">Carboxylic acid</span> Organic compound containing a –C(=O)OH group

In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is R−COOH or R−CO2H, with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.

<span class="mw-page-title-main">Organic compound</span> Chemical compound with carbon-hydrogen bonds

In chemistry, many authors consider an organic compound to be any chemical compound that contains carbon-hydrogen or carbon-carbon bonds, however, some authors consider an organic compound to be any chemical compound that contains carbon. The definition of "organic" versus "inorganic" varies from author to author, and is a topic of debate. For example, methane is considered organic, but whether some other carbon-containing compounds are organic or inorganic varies from author to author, for example halides of carbon without carbon-hydrogen and carbon-carbon bonds, and certain compounds of carbon with nitrogen and oxygen.

<span class="mw-page-title-main">Oxide</span> Chemical compound where oxygen atoms are combined with atoms of other elements

An oxide is a chemical compound containing at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– ion with oxygen in the oxidation state of −2. Most of the Earth's crust consists of oxides. Even materials considered pure elements often develop an oxide coating. For example, aluminium foil develops a thin skin of Al2O3 that protects the foil from further oxidation.

<span class="mw-page-title-main">Base (chemistry)</span> Type of chemical substance

In chemistry, there are three definitions in common use of the word base, known as Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century.

<span class="mw-page-title-main">Polythiophene</span>

Polythiophenes (PTs) are polymerized thiophenes, a sulfur heterocycle. The parent PT is an insoluble colored solid with the formula (C4H2S)n. The rings are linked through the 2- and 5-positions. Poly(alkylthiophene)s have alkyl substituents at the 3- or 4-position(s). They are also colored solids, but tend to be soluble in organic solvents.

In chemistry, radical initiators are substances that can produce radical species under mild conditions and promote radical reactions. These substances generally possess weak bonds—bonds that have small bond dissociation energies. Radical initiators are utilized in industrial processes such as polymer synthesis. Typical examples are molecules with a nitrogen-halogen bond, azo compounds, and organic and inorganic peroxides.

Squaric acid, also called quadratic acid because its four carbon atoms approximately form a square, is a diprotic organic acid with the chemical formula C4O2(OH)2.

<span class="mw-page-title-main">Pentacene</span> Hydrocarbon compound (C22H14) made of 5 fused benzene rings

Pentacene is a polycyclic aromatic hydrocarbon consisting of five linearly-fused benzene rings. This highly conjugated compound is an organic semiconductor. The compound generates excitons upon absorption of ultra-violet (UV) or visible light; this makes it very sensitive to oxidation. For this reason, this compound, which is a purple powder, slowly degrades upon exposure to air and light.

<span class="mw-page-title-main">Carbonate ester</span> Chemical group (R–O–C(=O)–O–R)

In organic chemistry, a carbonate ester is an ester of carbonic acid. This functional group consists of a carbonyl group flanked by two alkoxy groups. The general structure of these carbonates is R−O−C(=O)−O−R' and they are related to esters, ethers and also to the inorganic carbonates.

Di-<i>tert</i>-butyl dicarbonate Chemical compound

Di-tert-butyl dicarbonate is a reagent widely used in organic synthesis. Since this compound can be regarded formally as the acid anhydride derived from a tert-butoxycarbonyl (Boc) group, it is commonly referred to as Boc anhydride. This pyrocarbonate reacts with amines to give N-tert-butoxycarbonyl or so-called Boc derivatives. These carbamate derivatives do not behave as amines, which allows certain subsequent transformations to occur that would be incompatible with the amine functional group. The Boc group can later be removed from the amine using moderately strong acids. Thus, Boc serves as a protective group, for instance in solid phase peptide synthesis. Boc-protected amines are unreactive to most bases and nucleophiles, allowing for the use of the fluorenylmethyloxycarbonyl group (Fmoc) as an orthogonal protecting group.

<i>tert</i>-Butyloxycarbonyl protecting group Protecting group used in organic synthesis

The tert-butyloxycarbonyl protecting group or tert-butoxycarbonyl protecting group is a protecting group used in organic synthesis.

<span class="mw-page-title-main">Alkyl nitrites</span> Organic compounds of the form R–O–N=O

In organic chemistry, alkyl nitrites are a group of organic compounds based upon the molecular structure R−O−N=O, where R represents an alkyl group. Formally they are alkyl esters of nitrous acid. They are distinct from nitro compounds.

<span class="mw-page-title-main">Dimethyl carbonate</span> Chemical compound

Dimethyl carbonate (DMC) is an organic compound with the formula OC(OCH3)2. It is a colourless, flammable liquid. It is classified as a carbonate ester. This compound has found use as a methylating agent and more recently as a solvent that is exempt from the restrictions placed on most volatile organic compounds (VOCs) in the United States. Dimethyl carbonate is often considered to be a green reagent.

<span class="mw-page-title-main">Oxocarbon</span> Chemical compounds made of only carbon and oxygen

In chemistry, an oxocarbon or oxide of carbon is a chemical compound consisting only of carbon and oxygen. The simplest and most common oxocarbons are carbon monoxide (CO) and carbon dioxide. Many other stable or metastable oxides of carbon are known, but they are rarely encountered, such as carbon suboxide and mellitic anhydride.

<span class="mw-page-title-main">Acetylenedicarboxylic acid</span> Chemical compound

Acetylenedicarboxylic acid or butynedioic acid is an organic compound (a dicarboxylic acid) with the formula C4H2O4 or HO2CC≡CCO2H. It is a crystalline solid that is soluble in diethyl ether.

<span class="mw-page-title-main">Oxocarbon anion</span> Negatively-charged molecule made of carbon and oxygen

In chemistry, an oxocarbon anion is a negative ion consisting solely of carbon and oxygen atoms, and therefore having the general formula C
x
On
y
for some integers x, y, and n.

<span class="mw-page-title-main">Dicarbonate</span> Chemical compound

A dicarbonate, also known as a pyrocarbonate, is a chemical containing the divalent −O−C(=O)−O−C(=O)−O− or −C2O5 functional group, which consists of two carbonate groups sharing an oxygen atom. These compounds can be viewed as derivatives of the hypothetical compound dicarbonic acid, HO−C(=O)−O−C(=O)−OH or H2C2O5. Two important organic compounds containing this group are dimethyl dicarbonate H3C−C2O5−CH3 and di-tert-butyl dicarbonate(H3C−)3C−C2O5−C(−CH3)3.

<span class="mw-page-title-main">Tricarbonate</span> Chemical compound

In organic chemistry, a tricarbonate is a compound containing the divalent −O−C(=O)−O−C(=O)−O−C(=O)−O− functional group, which consists of three carbonate groups linked in a chain by sharing of oxygen oxygen atoms. These compounds can be viewed as derivatives of a hypothetical tricarbonic acid, HO−C(=O)−O−C(=O)−O−C(=O)−OH. An important example is di-tert-butyl tricarbonate(H3C−)3C−C3O7−C(−CH3)3, an intermediate in the synthesis of di-tert-butyl dicarbonate.

<i>tert</i>-Butyl peroxybenzoate Chemical compound

tert-Butyl peroxybenzoate (TBPB) an organic compound with the formula C6H5CO2CMe3 (Me = CH3). It is the most widely produced perester. It is often used as a radical initiator in polymerization reactions, such as the production of LDPE from ethylene, and for crosslinking, such as for unsaturated polyester resins.

References

  1. Bruna, Pablo J.; Grein, Friedrich; Passmore, Jack (2011). "Density functional theory (DFT) calculations on the structures and stabilities of [CnO2n+1]2– and [CnO2n+1]X2 polycarbonates containing chainlike (CO2)n units (n = 2–6; X = H or Li)". Canadian Journal of Chemistry. 89 (6): 671–687. doi:10.1139/v11-039.
  2. Pope, Barry M.; Yamamoto, Yutaka; Tarbell, D. Stanley (1977). "Di-tert-Butyl Dicarbonate". Organic Syntheses . 57: 45.; Collective Volume, vol. 6, 1988, p. 418
  3. Lewars, Errol (1996). "Polymers and oligomers of carbon dioxide: ab initio and semiempirical calculations". Journal of Molecular Structure: THEOCHEM. 363 (1): 1–5. doi:10.1016/0166-1280(95)04420-5.