Polyurethane refers to a class of polymers composed of organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane term does not refer to the single type of polymer but a group of polymers. Unlike polyethylene and polystyrene polyurethanes can be produced from a wide range of starting materials resulting various polymers within the same group. This chemical variety produces polyurethanes with different chemical structures leading to many different applications. These include rigid and flexible foams, and coatings, adhesives, electrical potting compounds, and fibers such as spandex and polyurethane laminate (PUL). Foams are the largest application accounting for 67% of all polyurethane produced in 2016.
In chemistry, a disulfide is a compound containing a R−S−S−R′ functional group or the S2−
2 anion. The linkage is also called an SS-bond or sometimes a disulfide bridge and usually derived from two thiol groups.
In organic chemistry, a thiol, or thiol derivative, is any organosulfur compound of the form R−SH, where R represents an alkyl or other organic substituent. The −SH functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group. Thiols are the sulfur analogue of alcohols, and the word is a blend of "thio-" with "alcohol".
Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water-miscible organic liquid with low viscosity. It is mainly used as a precursor to polymers. Being polar and having a wide liquid range, THF is a versatile solvent. It is an isomer of another solvent, butanone.
A diol is a chemical compound containing two hydroxyl groups. An aliphatic diol may also be called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified. They are used as protecting groups of carbonyl groups, making them essential in synthesis of organic chemistry.
In organic chemistry, free-radical addition is an addition reaction which involves free radicals. These reactions can happen due to the free radicals having an unpaired electron in their valence shell, making them highly reactive. Radical additions are known for a variety of unsaturated substrates, both olefinic or aromatic and with or without heteroatoms.
Cyclodextrins are a family of cyclic oligosaccharides, consisting of a macrocyclic ring of glucose subunits joined by α-1,4 glycosidic bonds. Cyclodextrins are produced from starch by enzymatic conversion. They are used in food, pharmaceutical, drug delivery, and chemical industries, as well as agriculture and environmental engineering.
In organic chemistry, a group transfer reaction is a class of the pericyclic reaction where one or more groups of atoms is transferred from one molecule to another. Group transfer reactions can sometimes be difficult to identify when separate reactant molecules combine into a single product molecule. Unlike other pericyclic reaction classes, group transfer reactions do not have a specific conversion of pi bonds into sigma bonds or vice versa, and tend to be less frequently encountered. Like all pericyclic reactions, group transfer reactions must obey the Woodward–Hoffmann rules. Group transfer reactions can be divided into two distinct subcategories: the ene reaction and the diimide reduction. Group transfer reactions have diverse applications in various fields, including protein adenylation, biocatalytic and chemoenzymatic approaches for chemical synthesis, and strengthening skim natural rubber latex.
The azide-alkyne Huisgen cycloaddition is a 1,3-dipolar cycloaddition between an azide and a terminal or internal alkyne to give a 1,2,3-triazole. Rolf Huisgen was the first to understand the scope of this organic reaction. American chemist Karl Barry Sharpless has referred to copper-catalyzed version of this cycloaddition as "the cream of the crop" of click chemistry and "the premier example of a click reaction".
Maleic anhydride is an organic compound with the formula C2H2(CO)2O. It is the acid anhydride of maleic acid. It is a colorless or white solid with an acrid odor. It is produced industrially on a large scale for applications in coatings and polymers.
Norbornene or norbornylene or norcamphene is a highly strained bridged cyclic hydrocarbon. It is a white solid with a pungent sour odor. The molecule consists of a cyclohexene ring with a methylene bridge between carbons 1 and 4. The molecule carries a double bond which induces significant ring strain and significant reactivity.
In organic chemistry, a cyclophane is a hydrocarbon consisting of an aromatic unit and a chain that forms a bridge between two non-adjacent positions of the aromatic ring. More complex derivatives with multiple aromatic units and bridges forming cagelike structures are also known. Cyclophanes are well-studied examples of strained organic compounds.
Organoselenium chemistry is the science exploring the properties and reactivity of organoselenium compounds, chemical compounds containing carbon-to-selenium chemical bonds. Selenium belongs with oxygen and sulfur to the group 16 elements or chalcogens, and similarities in chemistry are to be expected. Organoselenium compounds are found at trace levels in ambient waters, soils and sediments.
2-Mercaptoethanol (also β-mercaptoethanol, BME, 2BME, 2-ME or β-met) is the chemical compound with the formula HOCH2CH2SH. ME or βME, as it is commonly abbreviated, is used to reduce disulfide bonds and can act as a biological antioxidant by scavenging hydroxyl radicals (amongst others). It is widely used because the hydroxyl group confers solubility in water and lowers the volatility. Due to its diminished vapor pressure, its odor, while unpleasant, is less objectionable than related thiols.
Nanocomposite is a multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometers (nm) or structures having nano-scale repeat distances between the different phases that make up the material.
A dithiane is a heterocyclic compound composed of a cyclohexane core structure wherein two methylene bridges are replaced by sulfur. The three isomeric parent heterocycles are 1,2-dithiane, 1,3-dithiane and 1,4-dithiane. They are all colorless solids.
Basketane is a polycyclic alkane with the chemical formula C10H12. The name is taken from its structural similarity to a basket shape. Basketane was first synthesized in 1966, independently by Masamune and Dauben and Whalen. A patent application published in 1988 used basketane, which is a hydrocarbon, as a source material in doping thin diamond layers because of the molecule's high vapor pressure, carbon ring structure, and fewer hydrogen-to-carbon bond ratio.
In organic chemistry, the thiol-yne reaction is an organic reaction between a thiol and an alkyne. The reaction product is an alkenyl sulfide.
In organic chemistry, a dithiol is a type of organosulfur compound with two thiol functional groups. Their properties are generally similar to those of monothiols in terms of solubility, odor, and volatility. They can be classified according to the relative location of the two thiol groups on the organic backbone.
In organosulfur chemistry, the thiol-ene reaction is an organic reaction between a thiol and an alkene to form a thioether. This reaction was first reported in 1905, but it gained prominence in the late 1990s and early 2000s for its feasibility and wide range of applications. This reaction is accepted as a click chemistry reaction given the reactions' high yield, stereoselectivity, high rate, and thermodynamic driving force.
