1,8-Diazabicycloundec-7-ene on:
[Wikipedia]
[Google]
[Amazon]
1,8-Diazabicyclo .4.0ndec-7-ene, or more commonly DBU, is a
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
and belongs to the class of amidine
Amidines are organic compounds with the functional group RC(NR)NR2, where the R groups can be the same or different. They are the imine derivatives of amides (RC(O)NR2). The simplest amidine is formamidine, HC(=NH)NH2.
Examples of amidines includ ...
compounds. It is used in organic synthesis
Organic synthesis is a branch of chemical synthesis concerned with the construction of organic compounds. Organic compounds are molecules consisting of combinations of covalently-linked hydrogen, carbon, oxygen, and nitrogen atoms. Within the gen ...
as a catalyst
Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...
, a complexing ligand
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...
, and a non-nucleophilic base.
Synthesis
DBU can be synthesised in three steps fromcaprolactam
Caprolactam (CPL) is an organic compound with the chemical formula, formula (CH2)5C(O)NH. This colourless solid is a lactam (a cyclic amide) of caproic acid. Global demand for this compound is approximately five million tons per year, and the vast ...
and acrylonitrile
Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group () linked to a nitrile (). It is an im ...
. First, the nitrile undergoes an addition reaction
In organic chemistry, an addition reaction is an organic reaction in which two or more molecule
A molecule is a group of two or more atoms that are held together by Force, attractive forces known as chemical bonds; depending on context, ...
at the caprolactam nitrogen, producing ''N''-(2-cyanoethyl)-caprolactam. This is then hydrogenated
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organi ...
to ''N''-aminopropyl-caprolactam, followed by an intramolecular carbonyl condensation to form the imine. Water
Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...
is removed by fractional distillation.
Occurrence
Although all commercially available DBU is produced synthetically, it may also be isolated from the sea sponge '' Niphates digitalis''. The biosynthesis of DBU has been proposed to begin with adipaldehyde and1,3-diaminopropane
1,3-Diaminopropane, also known as , is a simple diamine with the formula H2N(CH2)3NH2. A colourless liquid with a fishy odor, it is soluble in water and many polar organic solvents. It is isomeric with 1,2-diaminopropane. Both are building blocks ...
.
Applications
DBU is used: * As areagent
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...
in organic chemistry, where DBU is used as a ligand and base. As a base, protonation occurs at the imine nitrogen. Lewis acids also attach to the same nitrogen.
* As a catalyst, for example as a curing agent for epoxy
Epoxy is the family of basic components or Curing (chemistry), cured end products of epoxy Resin, resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide fun ...
resins and polyurethane
Polyurethane (; often abbreviated PUR and PU) is a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethane term ...
.
* In the separation of fullerene
A fullerene is an allotropes of carbon, allotrope of carbon whose molecules consist of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to six atoms. The molecules may ...
s in conjunction with trimethylbenzene. It reacts with C70 and higher fullerenes, but not with C60.
* As a dehydrohalogenation
In chemistry, dehydrohalogenation is an elimination reaction which removes a hydrogen halide from a substrate (chemistry), substrate. The reaction is usually associated with the synthesis of alkenes, but it has wider applications.
Dehydrohalogen ...
agent.
* In surface activation products ( primers) for low-surface energy
In surface science, surface energy (also interfacial free energy or surface free energy) quantifies the disruption of intermolecular bonds that occurs when a surface is created. In solid-state physics, surfaces must be intrinsically less energe ...
plastics and elastomers (such as PTFE
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off fro ...
, HDPE
High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or " polythene" when used for HDPE pipes. With a high strength-to-density ratio ...
, PP, and silicone rubber
Silicone rubber is an elastomer composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulations. Silicone rubbers ar ...
), where DBU raises the surface energy enough for adhesives (such as cyanoacrylate
Cyanoacrylates are a family of strong fast-acting adhesives with industrial, medical, and household uses. They are derived from ethyl cyanoacrylate and related esters. The cyanoacrylate group in the monomer rapidly polymerizes in the presence ...
and contact cement) to bond to these otherwise inert, non-stick materials.
See also
* 1,5-Diazabicyclo .3.0on-5-ene *DABCO
DABCO (1,4-diazabicyclo .2.2ctane), also known as triethylenediamine or TEDA, is a bicyclic organic compound with the formula N2(C2H4)3. This colorless solid is a highly nucleophilic tertiary amine base, which is used as a catalyst and reagent in ...
References