Tri-n-octylphosphine oxide

• CAT Number: R070991
• CAS Number: 78-50-2
• Molecular Formula: C24H51OP
• Molecular Weight: 386.645
• Purity: ≥95%
• Storage: RT
• IUPAC Name: 1-dioctylphosphoryloctane
• InChI: InChI=1S/C24H51OP/c1-4-7-10-13-16-19-22-26(25,23-20-17-14-11-8-5-2)24-21-18-15-12-9-6-3/h4-24H2,1-3H3
• InChIKey: ZMBHCYHQLYEYDV-UHFFFAOYSA-N
• SMILES: CCCCCCCCP(=O)(CCCCCCCC)CCCCCCCC

TOPO(CAS: 78-50-2) is usually prepared by oxidation of trioctylphosphine, which in turn is produced by alkylation of phosphorus trichloride. The main use of TOPO is in solvent extraction of metals, especially uranium. The high lipophilicity and high polarity are properties key to this application. Its high polarity, which results from the dipolar phosphorus-oxygen bond, allows this compound to bind to metal ions. The octyl groups confer solubility in low polarity solvents such as kerosene. In the research laboratory, both trioctylphosphine and TOPO are frequently useful as a capping ligand for the production of quantum dots such as those consisting of CdSe. In these cases, TOPO serves as solvent for the synthesis and solubilizes the growing nanoparticles. TOPO-coated quantum dots are typically soluble in chloroform, toluene, and (to a lesser extent) hexane. These quantum dots are also used in biological applications as part of the protective barrier to prevent degradation as it travels through the harsh climate of the body.

Reference

[1]. Phys Chem Chem Phys. 2020 Nov 14;22(42):24744-24763. doi: 10.1039/d0cp02605k. Epub 2020 Oct 27.
Hydrophobic functional liquids based on trioctylphosphine oxide (TOPO) and carboxylic acids.
Byrne EL (1), O'Donnell R , Gilmore M , Artioli N , Holbrey JD , Swadźba-Kwaśny M .
Author information: (1)The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK. .
Trioctylphosphine oxide (TOPO) is a hydrophobic extracting agent used in a number of commercially important separations of valuable solutes from aqueous streams (with examples ranging from lanthanides, through gallium, to carboxylic acids). TOPO is traditionally used as a solute in kerosene, its extraction efficiency limited by its solubility in the organic diluents. In this work, eighteen hydrogen bond donors (HBDs) were screened for their capacity to liquefy TOPO, employing strategies used to design deep eutectic solvents (DES). The selected HBDs were all useful in separations and were designed to formulate solvent-free, hydrophobic, bi-functional liquid extracting agents. Some TOPO:HBD mixtures yielded hydrophobic liquids that offer potential to be extremely efficient extractants, incorporating high intrinsic concentrations of TOPO. Following this initial screening, two systems: TOPO:malonic acid and TOPO:levulinic acid, were selected for detailed physico-chemical characterisation across their complete compositional ranges. Phase diagrams, thermal stabilities and the mechanism of thermal decomposition are reported, along with densities and insights from 31P NMR spectroscopic studies. The work was concluded with a proof-of-concept demonstration of the use of the TOPO:malonic acid (2 : 1 mol ratio) mixture for the extraction of gallium from acidic chloride feedstock (simulated pre-digestate of zinc leach residue). The loading capacity of the TOPO:malonic acid extractant was three orders of magnitude greater than that of the literature benchmark, encouraging further application-oriented studies.
DOI: 10.1039/d0cp02605k PMID: 33107499

[2]. Langmuir. 2017 Nov 7;33(44):12689-12696. doi: 10.1021/acs.langmuir.7b02963. Epub 2017 Oct 27.
Improving the Stability and Size Tunability of Cesium Lead Halide Perovskite Nanocrystals Using Trioctylphosphine Oxide as the Capping Ligand.
Wu L(1), Zhong Q(1), Yang D(1), Chen M(1), Hu H(1), Pan Q(1), Liu H(1), Cao M(1), Xu Y(1), Sun B(1), Zhang Q(1).
Author information: (1)Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , Suzhou, Jiangsu 215123, P. R. China.
Recently, all-inorganic cesium lead halide (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) have drawn wide attention because of their excellent optoelectronic properties and potential applications. However, one of the most significant challenges of such NCs is their low stability against protonic solvents. In this work, we demonstrate that by incorporating a highly branched capping ligand, trioctylphosphine oxide (TOPO), into the traditional oleic acid/oleylamine system, monodisperse CsPbX3 NCs with excellent optoelectronic properties can be achieved at elevated temperatures (up to 260 °C). The size of such NCs can be varied in a relatively wide range. The capping of TOPO on NCs has been verified through Fourier transform infrared spectroscopy measurement. More importantly, the presence of TOPO can dramatically improve the stability of CsPbX3 NCs against ethanol treatment. After ethanol treatment for 100 min, the emission intensity of the TOPO-capped sample dropped only 5%, whereas that of non-TOPO-capped NCs dropped up to 86%. This work may shed some light on the preparation and application of CsPbX3 NCs with higher stability.
DOI: 10.1021/acs.langmuir.7b02963 PMID: 29032682

[3]. Acta Crystallogr C Struct Chem. 2015 Mar;71(Pt 3):239-41. doi: 10.1107/S2053229615003009. Epub 2015 Feb 21.
Structure determination and modeling of monoclinic trioctylphosphine oxide.
Doan-Nguyen VV(1), Carroll PJ(2), Murray CB(1).
Author information: (1)Department of Materials Science and Engineering, University of Pennsylvania, 3231 Walnut Street, Philadephia, PA 19104, USA. (2)Department of Chemistry, University of Pennsylvania, 231 S. 34th Street, Philadephia, PA 19104, USA.
Trioctylphosphine oxide (TOPO), C(24)H(51)OP, was recrystallized from ambient evaporation in acetone. TOPO single crystals form with a monoclinic P2(1)/c structure. Fourier transform IR (FT-IR) spectroscopy captures the characteristic stretching modes from the seven methylene groups, the phosphoryl P=O bond, and the phosphoryl-carbon bond.
DOI: 10.1107/S2053229615003009 PMID: 25734856

[4]. Spectrochim Acta A Mol Biomol Spectrosc. 2015 Feb 5;136 Pt B:288-94. doi: 10.1016/j.saa.2014.08.133. Epub 2014 Oct 5.
Investigation on the trioctylphosphine oxide-based super-concentrated HCl system.
Guo R(1), Guo L(2), Huang K(3), He A(1), Zhang J(2), Zheng L(4), Liu Y(5), Kang T(6), Gao X(1), Weng S(1), Zhao Y(7), Yang Z(1), Xu Y(1), Noda I(8), Wu J(1).
Author information: (1)College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. (2)College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; College of Pharmacy, Liaoning University of Traditional Chinese Medicine, Dalian 116600, China. (3)College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. (4)Beijing Synchrotron Radiation Facility (BSRF), Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China. (5)Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China. (6)College of Pharmacy, Liaoning University of Traditional Chinese Medicine, Dalian 116600, China. (7)Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. (8)Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, United States.
We report a new super-concentrated HCl system prepared by using trioctylphosphine oxide (TOPO)-based reverse micelles. The observed molar ratio between acid and water (nHCl/nH2O) in the super-concentrated HCl are much higher than that in the saturated aqueous HCl solution (0.28). Moreover, FT-IR spectroscopic results reveal that a significant amount of HCl remains in the molecular form rather than being ionized into H(+) and Cl(-). As a result, two H-Cl stretching bands can be observed in the FT-IR spectrum. The super-concentrated HCl provides a unique chemical environment in which many chemical substances occur in unusual states. For example, the color of super-concentrated HCl solution containing copper ion was found to be reddish brown rather than green as in conventional state. UV-Vis-NIR spectral results indicate that both d-d transition band of Cu(2+) and charge transfer band of Cl-Cu in super-concentrated HCl underwent significant variation. Additionally, copper ions bring about remarkable variation on the hydrogen bond network among HCl in the super-concentrated HCl solution as demonstrated by FT-IR spectra. According to the EXAFS results, we suggest that copper ion may occur as HCuCl3 in the super-concentrated HCl.
Copyright © 2014 Elsevier B.V. All rights reserved.
DOI: 10.1016/j.saa.2014.08.133 PMID: 25448932

[5]. Chemosphere. 2016 Jun;153:405-13. doi: 10.1016/j.chemosphere.2016.03.053. Epub 2016 Mar 28.
Solid/liquid extraction equilibria of phenolic compounds with trioctylphosphine oxide impregnated in polymeric membranes.
Praveen P(1), Loh KC(2).
Author information: (1)Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore. (2)Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore. Electronic address: .
Trioctylphosphine oxide based extractant impregnated membranes (EIM) were used for extraction of phenol and its methyl, hydroxyl and chloride substituted derivatives. The distribution coefficients of the phenols varied from 2 to 234, in the order of 1-napthol > p-chlorophenol > m-cresol > p-cresol > o-cresol > phenol > catechol > pyrogallol > hydroquinone, when initial phenols loadings was varied in 100-2000 mg/L. An extraction model, based on the law of mass action, was formulated to predict the equilibrium distribution of the phenols. The model was in excellent agreement (R(2) > 0.97) with the experimental results at low phenols concentrations (<800 mg/L). At higher phenols loadings though, Langmuir isotherm was better suited for equilibrium prediction (R(2) > 0.95), which signified high mass transfer resistance in the EIMs. Examination of the effects of ring substitution on equilibrium, and bivariate statistical analysis between the amounts of phenols extracted into the EIMs and factors affecting phenols interaction with TOPO, indicated the dominant role of hydrophobicity in equilibrium determination. These results improve understanding of the solid/liquid equilibrium process between phenols and the EIMs, and these will be useful in designing phenol recovery process from wastewater.
Copyright © 2016 Elsevier Ltd. All rights reserved.
DOI: 10.1016/j.chemosphere.2016.03.053 PMID: 27031803