Tetrapropylammonium (TPA) is a quaternary ammonium cation with the formula [N(C3H7)4]+, also denoted [NPr4]+ (where Pr = propyl group). It is a precursor to several significant industrial and laboratory catalysts.
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| Names | |
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| IUPAC name
N,N,N-Tripropylpropan-1-aminium
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| Other names
Tetrapropylammonium
Tetrapropylazanium Tetra-n-propylammonium TPA | |
| Identifiers | |
3D model (JSmol)
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| 1748523 | |
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| C12H28N+ | |
| Molar mass | 186.362 g·mol−1 |
| Structure | |
| Tetrahedral | |
| Related compounds | |
Other cations
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Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Properties
editTPA is chemically similar to other quaternary ammonium cations with saturated alkyl groups. As such, it is highly electrochemically stable, degrading only in the presence of particularly strong bases and nucleophiles.[1]
It is isoelectronic with tetrapropyltin and the tetrapropylboranuide anion.
Synthesis
editLike other quaternary ammonium cations, TPA is prepared by the alkylation of the corresponding ammonia analogue, tripropylamine. Treatment of the amine with a primary propyl halide such as n-bromopropane yields the corresponding TPA halide salt in a Menshutkin reaction:
- (C3H7)3N + C3H7Br → (C3H7)4N+Br−
The halide salts are then converted to the more industrially valuable hydroxide by reaction with aqueous silver oxide, electrolysis, ion-exchange resin, or electrodialysis.[2]
Applications
editThe tetrapropylammonium cation is used as a structure-directing agent in the production of synthetic zeolites, in particular ZSM-5[3] and titanium-bearing TS-1 catalysts.[4] After synthesis, TPA is removed by thermolysis.[5]
The TPA salt tetrapropylammonium perruthenate (TPAP) is an effective and highly selective oxidiser, with numerous applications in organic synthesis.[6][7] Combined with a cooxidant, it serves as a catalyst for the oxidation of primary and secondary alcohols to aldehydes and ketones.
References
edit- ^ Mousavi, Maral P. S.; Kashefolgheta, Sadra; Stein, Andreas; Bühlmann, Philippe (2016). "Electrochemical Stability of Quaternary Ammonium Cations: An Experimental and Computational Study". Journal of the Electrochemical Society. 163 (2): H74–H80. doi:10.1149/2.0671602jes. hdl:11858/00-001M-0000-0029-2301-3.
- ^ Shen, Jiang-nan; Yu, Jie; Huang, Jie; Van Der Bruggen, Bart (2013), "Preparation of highly pure tetrapropyl ammonium hydroxide using continuous bipolar membrane electrodialysis", Chemical Engineering Journal, 220: 311–319, Bibcode:2013ChEnJ.220..311S, doi:10.1016/j.cej.2013.01.040
- ^ Li, Teng; Krumeich, Frank; Chen, Ming; Ma, Zhiqiang; Van Bokhoven, Jeroen A. (2020). "Defining aluminum-zoning during synthesis of ZSM-5 zeolites". Physical Chemistry Chemical Physics. 22 (2): 734–739. Bibcode:2020PCCP...22..734L. doi:10.1039/C9CP05423E. hdl:20.500.11850/383611. PMID 31832632.
- ^ Yang, Zhenyuan; Guan, Yanan; Xu, Lei; Zhou, Yangtao; Fan, Xiaolei; Jiao, Yilai (2023). "Tetrapropylammonium Hydroxide Treatment of Aged Dry Gel to Make Hierarchical TS-1 Zeolites for Catalysis". Crystal Growth & Design. 23 (3): 1775–1785. doi:10.1021/acs.cgd.2c01291. PMC 9983304. PMID 36879771.
- ^ Choudhary, V. (1985). "Influence of decomposition conditions of TPA-ZSM-5 on surface and catalytic properties of the resulting H a Na-ZSM-5". Journal of Catalysis. 94 (2): 573–575. doi:10.1016/0021-9517(85)90224-6.
- ^ Ley, Steven V.; Norman, Joanne; Griffith, William P.; Marsden, Stephen P. (1994). "Tetrapropylammonium Perruthenate, Pr4N+RuO4 -, TPAP: A Catalytic Oxidant for Organic Synthesis". Synthesis. 1994 (7): 639–666. doi:10.1055/s-1994-25538.
- ^ Langer, Peter (2000). "Tetra-n-propyl Ammonium Perruthenate (TPAP) - an Efficient and Selective Reagent for Oxidation Reactions in Solution and on the Solid Phase". Journal für Praktische Chemie. 342 (7): 728–730. doi:10.1002/1521-3897(200009)342:7<728::AID-PRAC728>3.3.CO;2-I.