Phase-transfer catalyst

In <a href="/facts/Chemistry/SrNqkGVm">chemistry</a>, a phase-transfer catalyst or PTC is a <a href="/facts/Catalyst/LPBS7TQC">catalyst</a> that facilitates the <a href="/facts/Phase_transition/eLP2BY8R">transition</a> of a <a href="/facts/Reactant/c3GLInCu">reactant</a> from one <a href="/facts/Phase_(matter)/NkHXDdN3">phase</a> into another phase where reaction occurs. Phase-transfer catalysis is a special form of catalysis and can act through <a href="/facts/Homogeneous_catalysis/c7wplnb2">homogeneous catalysis</a> or <a href="/facts/Heterogeneous_catalysis/ju7E0bab">heterogeneous catalysis</a> methods depending on the catalyst used. <a href="/facts/Ionic_compound/jB9nMfrE">Ionic</a> reactants are often <a href="/facts/Soluble/kLE9h3Jb">soluble</a> in an <a href="/facts/Aqueous/eRNr3MH2">aqueous</a> phase but insoluble in an organic phase in the absence of the phase-transfer catalyst. The catalyst functions like a <a href="/facts/Detergent/4FLKXR6p">detergent</a> for solubilizing the <a href="/facts/Salts/lsSKwGpn">salts</a> into the organic phase. Phase-transfer catalysis refers to the acceleration of the reaction upon the addition of the phase-transfer catalyst. PTC is widely exploited industrially. <a href="/facts/Polyester/Ivp9CHpl">Polyesters</a> for example are prepared from acyl chlorides and <a href="/facts/Bisphenol_A/8AAPhAh0">bisphenol-A</a>. Phosphothioate-based pesticides are generated by PTC-catalyzed <a href="/facts/Alkylation/1rd5SNbt">alkylation</a> of phosphothioates.

In ideal cases, PTC can be fast and efficient, minimizing the need for expensive or dangerous solvents and simplifying purification Phase-transfer catalysts are especially useful in <a href="/facts/Green_chemistry/7csVY28w">green chemistry</a>—by allowing the use of water, the need for <a href="/facts/Organic_solvent/LoMPMz8S">organic solvents</a> is lowered.
Phase-boundary catalysis (PBC) is a type of <a href="/facts/Heterogeneous_catalysis/ju7E0bab">heterogeneous catalytic system</a> which facilitates the <a href="/facts/Chemical_reaction/GpqWlKrz">chemical reaction</a> of a particular chemical component in an immiscible phase to react on a catalytic active site located at a <a href="/facts/Phase_boundary/DFPxGkVx">phase boundary</a>. The chemical component is soluble in one phase but insoluble in the other. The <a href="/facts/Catalyst/LPBS7TQC">catalyst</a> for PBC has been designed in which the external part of the <a href="/facts/Zeolite/SNrXy4v2">zeolite</a> is <a href="/facts/Hydrophobic/Ifya0CXQ">hydrophobic</a>, internally it is usually <a href="/facts/Hydrophilic/k8p95WYu">hydrophilic</a>, notwithstanding to polar nature of some reactants. In this sense, the medium environment in this system is close to that of an <a href="/facts/Enzyme/DSI1Fh7y">enzyme</a>. The major difference between this system and <a href="/facts/Enzyme/DSI1Fh7y">enzyme</a> is lattice flexibility. The lattice of <a href="/facts/Zeolite/SNrXy4v2">zeolite</a> is rigid, whereas the <a href="/facts/Enzyme/DSI1Fh7y">enzyme</a> is flexible.

Phase-transfer catalyst open-in-new

Phase-transfer catalyst