Figure 1. Basic information about allene
Allene is an organic compound that consists of three carbon atoms joined on a linear chain by two double bonds.
These compounds are collectively called Allene. The most basic structure of allenes is propadiene. Propadiene is sometimes referred to as Allene.
Propadiene can be synthesized by the action of zinc powder on an ethanol solution of 2,3-dibromopropene or 2,3-dichloropropene. On the other hand, when propadiene absorbs sulfuric acid and is distilled with water, it becomes acetone.
Propadiene, "Allene" in the narrow sense, is used as a component of MAPP gas MAPP gas is a mixture of propadiene and methylacetylene MAPP gas is used for soldering and welding. It is safe and easy to transport, but is not cost-effective.
Compounds classified as "Allene" in the broad sense of the word are not used much industrially. However, Allene is highly reactive and can undergo a variety of addition reactions, making it a promising candidate for use in useful chemical reactions. Allene is characterized by its axial chirality.
The chemical properties of allenes differ significantly from those of common alkenes. Allene is very unstable when compared to conjugated and isolated dienes. The C-H bonds in Allene are weaker and more acidic than the C-H bonds in vinyl groups.
Allene undergoes [2+2] and [4+2] cycloaddition reactions. Formal cycloaddition reactions proceed when transition metal catalysts are used.
Propadiene, the most basic structure of Allene, is a colorless gas with a sweet odor. It has a melting point of -136.3°C and a boiling point of -34.4°C. It is virtually insoluble in water. It decomposes easily, but is highly stable and is used as a welding fuel along with methylacetylene.
Figure 2. Synthesis of allene
A structure with two or more consecutive double bonds, as in Allene, is called an integrated double bond. The chemical formula is R2C=C=CR2. The name for a compound with three or more double bonds in a row is cumulene. Substituents such as R2C=C=CR-, where R is an alkyl group of Allene, are called allenyl groups.
The most basic structure of allene, propadiene, has the chemical formula H2C=C=CH2. Propadiene exists in equilibrium with methylacetylene, which has the chemical formula H3C-C3≡CH. Special synthetic methods are often required for the synthesis of Allene. However, industrially, propadiene is synthesized from a mixture with methylacetylene.
The central carbon atom of Allene has two sigma and two pi bonds. The two terminal carbon atoms have sp2 hybrid orbitals. The three carbon atoms form a linear structure with a bond angle of 180°. The two terminal carbon atoms form a planar structure, with each plane twisted 90° in configuration.
The Allene molecule is often compared to a two-winged propeller. That is, Allene has four substituents and two 2-fold rotational symmetry axes C2 inclined at 45° from two different terminal CH2 planes through the central carbon atom.
There is a third two-fold rotational symmetry axis along the C=C=C bond axis, and the two CH2 planes are both mirror symmetry planes. Based on the above, the symmetry of the Allene molecule belongs to the point group D2d, and Allene without substituents is a nonpolar molecule with no total dipole moment.
Figure 3. Isomers of allenes
Derivatives in which two carbon atoms of the Allene molecule are bonded to two different substituents have mirror-image isomers. The R and S configurations can be determined by the priority of the substituents when the Allene molecule is viewed along its axis. The front side is preferred over the back side, which is determined by the relative arrangement of the front and back sides.
Thus, Allene has unusual optical properties and is used as a building block in the synthesis of organic materials.
*Including some distributors, etc.
Sort by Features
Sort by Area
Alfa Chemistry, founded in the year 2015 is based in New York, USA as a biotechnology company and manufacturer of graphene materials. Their product portfolio includes graphene oxide, CVD graphene film, graphene modification services, graphene series, graphene-like material, carbon nanomaterials, quantum dots, upcoming nanoparticles, and graphene transfer services. The company also provides services in custom manufacturing, and graphene analysis with quality assurance. The products are used in various industries which include energy, digital electronics, environment, textile, coating, and biomedical science.
TCI America (TCI) was founded in 1946 and is a worldwide manufacturer of specialty organic chemicals. The company produces organic laboratory chemicals as well as pharmaceutical, cosmetic, and functional materials. TCI’s product segments include Chemistry, Life Science, Materials Science, Analytical Chemistry, and Custom & Bulk. For materials science, the company manufactures battery materials, nanocarbon materials, and magnetic materials. For life sciences, the company produces antibodies, reagents, and chemicals for cancer research. The company produces HLC, NMR, various chemicals, and resins and media for analytical chemistry.
Millipore Sigma, formerly known as Sigma-Aldrich, was created in 175 through the merger of Sigma Chemical Company and Aldrich Chemical company and today is a subsidiary of Merck. Millipore Sigma is a life science and biotechnology company serving the industry with several products and services. Some of their product categories include peptide synthesis materials, biochemicals, building blocks, catalysts, chemical biology, chemical synthesis, flavors & fragrances, formulation, lab chemicals, lab safety, APIs, and stable isotopes. Services include characterization, contract manufacturing, custom products, software, support, testing, and mRNA development & manufacturing.
MuseChem Chemicals is an American chemical supplier located in Fairfield, New Jersey. They offer a wide range of products, including inhibitors and agonists, active pharmaceutical ingredients (APIs), and specialty chemicals. Research chemicals such as chemical reagents, bioactive chemicals, catalysts, and ligands are also part of their product offerings. MuseChem provides various services, including custom synthesis research of organic compounds for the agrochemical, chemical, and pharmaceutical industries. They also offer peptide synthesis services, ranging from bulk API peptides production to complex peptide modifications. Moreover, MuseChem offers bioconjugation services to create functional biomolecules for biomarker imaging, protein biodistribution, and cellular event tracking.
pH Scientific, established in 2015 and based in Auckland, New Zealand, operates as a distributor of laboratory supplies through its online platform. The company provides access to multiple suppliers through its online platform, serving as an intermediary connecting buyers to multiple suppliers. Its product range spans laboratory supplies such as bovine serum albumin for ELISAs, laboratory glassware like Eisco glass petri dishes, medical supplies like prednisone tablets, personal protective equipment including Biobase disposable face masks, and lab equipment like Eisco test tube stands. These offerings cater to diverse laboratory needs.
CATO Research Chemicals Inc. is headquartered in Guangzhou City, Guangdong Province, in China. The company performs research and development and production of more than 32000 standard products and 48000 analytical reference material products for manufacturing, agriculture, pharmaceutical, and chemical markets. The company distributes a range of chemicals from raw materials to intermediates to analytical testing and customized synthetic compounds. The categories of chemicals that the company sells include plant growth regulators, polychlorinated biphenyls, volatile organic compounds, ketones, and fatty alcohols.