1
|
Wood ZA, Castro EC, Nguyen AN, Fieser ME. Conversion of waste poly(vinyl chloride) to branched polyethylene mediated by silylium ions. Chem Sci 2024; 15:8766-8774. [PMID: 38873082 PMCID: PMC11168076 DOI: 10.1039/d4sc00130c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/18/2024] [Indexed: 06/15/2024] Open
Abstract
Full dechlorination of poly(vinyl chloride) (PVC) in a controlled manner to yield useful polymeric and chlorinated products is of great interest for the processing of PVC waste. Forming polyethylene (PE) without corrosive by-products would allow for a pre-treatment of PE wastes that are often contaminated with PVC. Herein, full dechlorination of PVC has been achieved via generation of silylium ions in situ, to furnish PE products. Complete dechlorination of PVC can be achieved in 2 hours, yielding organic polymer that has similar spectroscopic and thermal signatures of branched PE, with no observable chlorine. The degree of branching can be tuned between 31 and 57 branches per 1000 carbons, with melting temperatures ranging from 51 to 93 °C. This method is applicable to not only pure PVC, but also commercial PVC products. Depending on if the PVC products are separated from plasticizers, different melting points of the resulting PE are observed. PVC dechlorination in the presence of PE waste is also shown. This is the first report of being able to cleanly convert PVC waste to PE in high yields and tune the thermal properties of the PE product, highlighting the remarkable control that silylium ion mediated transformations enables compared to past chemical methods.
Collapse
Affiliation(s)
- Zachary A Wood
- Department of Chemistry, University of Southern California Los Angeles CA 91706 USA
| | - Eunice C Castro
- Department of Chemistry, University of Southern California Los Angeles CA 91706 USA
| | - Angelyn N Nguyen
- Department of Chemistry, University of Southern California Los Angeles CA 91706 USA
| | - Megan E Fieser
- Department of Chemistry, University of Southern California Los Angeles CA 91706 USA
- Wrigley Institute for Environment and Sustainability University of Southern California Los Angeles CA 91706 USA
| |
Collapse
|
2
|
Mondal H, Chattaraj PK. Frustrated Lewis pair-mediated hydro-dehalogenation: crucial role of non-covalent interactions. J Mol Model 2024; 30:198. [PMID: 38842625 DOI: 10.1007/s00894-024-05997-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 05/27/2024] [Indexed: 06/07/2024]
Abstract
CONTEXT Organic halides stand as invaluable reagents with diverse applications in synthetic chemistry and various industrial processes. Despite their utility, concerns arise due to their inherent toxicity. Addressing these apprehensions, hydro-dehalogenation has emerged as a promising strategy involving the replacement of halogen atoms with hydrogen atoms to transform toxic organic halides into hydrocarbons. This study delves into the computational exploration of hydro-dehalogenation reactions of benzyl halide, mediated by frustrated Lewis pairs (FLPs), using density functional theory (DFT). The reactions entail the formation of FLP1 or FLP2 in the presence of TMP or lutidine with B(C6F5)3, respectively. This is followed by heterolytic cleavage of dihydrogen and subsequent reaction with benzyl halides. Non-covalent interaction analysis underscores the significance of π-π stacking and CH-π interactions in stabilizing transition states. Additionally, the activation strain model (ASM) dissects activation energies, revealing the substantial impact of strain energy on reaction barriers. Energy decomposition analysis (EDA) offers insights into the contributions of electrostatic, orbital, and dispersion energies to the overall attractive interaction energy. The investigation extends to hydro-dehalogenation reactions of ethyl halides, uncovering distinct mechanisms and activation barriers. This comprehensive analysis illuminates the intricacies of hydro-dehalogenation reactions, providing valuable insights into their mechanisms and paving the way for future studies in this field. METHODS Geometry optimizations were carried out at the M06-2X/def2-SVP level of theory, which was performed using the Gaussian 16 program. Solvent-corrected single-point energies were also calculated using the polarizable continuum model (PCM) at the PCM(chloroform)-M06-2X/def2-TZVP//M06-2X/def2-SVP level of theory. The Gibbs free energy correction was determined from computations performed at the M06-2X/def2-SVP level of theory. Principal interacting orbital (PIO) analysis was conducted using the NBO 6.0 software. The nature of bonding in the respective transition state (TS) structures was analyzed using atoms-in-molecules (AIM) analyses. Additionally, the presence of non-covalent interactions (NCI) was exemplified using Multiwfn software.
Collapse
Affiliation(s)
- Himangshu Mondal
- Department of Chemistry, Indian Institute of Technology, Kharagpur, 721302, India
| | - Pratim Kumar Chattaraj
- Department of Chemistry, Birla Institute of Technology, Mesra, Ranchi, 835215, Jharkhand, India.
| |
Collapse
|
3
|
Gao J, Ge Y, He C. X-type silyl ligands for transition-metal catalysis. Chem Soc Rev 2024; 53:4648-4673. [PMID: 38525837 DOI: 10.1039/d3cs00893b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Given the critical importance of novel ligand development for transition-metal (TM) catalysis, as well as the resurgence of the field of organosilicon chemistry and silyl ligands, to summarize the topic of X-type silyl ligands for TM catalysis is highly attractive and timely. This review particularly emphasizes the unique σ-donating characteristics and trans-effects of silyl ligands, highlighting their crucial roles in enhancing the reactivity and selectivity of various catalytic reactions, including small molecule activation, Kumada cross-coupling, hydrofunctionalization, C-H functionalization, and dehydrogenative Si-O coupling reactions. Additionally, future developments in this field are also provided, which would inspire new insights and applications in catalytic synthetic chemistry.
Collapse
Affiliation(s)
- Jihui Gao
- School of Chemistry and Chemical Engineering, Heilongjiang Provincial, Harbin Institute of Technology, Harbin, Heilongjiang 150080, China
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
| | - Yicong Ge
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
| | - Chuan He
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
| |
Collapse
|
4
|
Wang T, Xu M, Jupp AR, Chen SM, Qu ZW, Grimme S, Stephan DW. Frustrated Lewis pair catalyzed hydrodehalogenation of benzyl-halides. Chem Commun (Camb) 2022; 58:1175-1178. [PMID: 34981087 DOI: 10.1039/d1cc05943b] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
10 mol% B(2,6-C6F2H3)3 in the presence of excess tetramethylpiperidine (TMP) and H2 (or D2) is shown to catalyze the hydrogenative dehalogenation of benzyl-halides to give corresponding toluene derivatives. These reactions proceed via an initial FLP activation of H2 yielding the ammonium hydridoborate [TMPH][HB(2,6-C6F2H3)3]. This species acts in analogy to a FLP to cooperatively activate C-X bond (X = Cl, Br, I) of benzyl-halides delivering hydride and generating the corresponding ammonium halide salts.
Collapse
Affiliation(s)
- Tongtong Wang
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON, M5S3H6, Canada. .,College of Chemistry, Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116023, China
| | - Maotong Xu
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON, M5S3H6, Canada.
| | - Andrew R Jupp
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON, M5S3H6, Canada.
| | - Shi-Ming Chen
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON, M5S3H6, Canada.
| | - Zheng-Wang Qu
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4, Bonn 53115, Germany.
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4, Bonn 53115, Germany.
| | - Douglas W Stephan
- Department of Chemistry, University of Toronto, 80 St. George St, Toronto, ON, M5S3H6, Canada.
| |
Collapse
|
5
|
Schmidt TA, Ciszek B, Kathe P, Fleischer I. Tandem Acid/Pd-Catalyzed Reductive Rearrangement of Glycol Derivatives. Chemistry 2020; 26:3641-3646. [PMID: 31951298 PMCID: PMC7154628 DOI: 10.1002/chem.202000251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Indexed: 11/05/2022]
Abstract
Herein, we describe the acid/Pd-tandem-catalyzed transformation of glycol derivatives into terminal formic esters. Mechanistic investigations show that the substrate undergoes rearrangement to an aldehyde under [1,2] hydrogen migration and cleavage of an oxygen-based leaving group. The leaving group is trapped as its formic ester, and the aldehyde is reduced and subsequently esterified to a formate. Whereas the rearrangement to the aldehyde is catalyzed by sulfonic acids, the reduction step requires a unique catalyst system comprising a PdII or Pd0 precursor in loadings as low as 0.75 mol % and α,α'-bis(di-tert-butylphosphino)-o-xylene as ligand. The reduction step makes use of formic acid as an easy-to-handle transfer reductant. The substrate scope of the transformation encompasses both aromatic and aliphatic substrates and a variety of leaving groups.
Collapse
Affiliation(s)
- Tanno A Schmidt
- Institute of Organic Chemistry, Faculty of Mathematics and Natural Sciences, Eberhard-Karls University Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.,current address: Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Benjamin Ciszek
- Institute of Organic Chemistry, Faculty of Mathematics and Natural Sciences, Eberhard-Karls University Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Prasad Kathe
- Institute of Organic Chemistry, Faculty of Mathematics and Natural Sciences, Eberhard-Karls University Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Ivana Fleischer
- Institute of Organic Chemistry, Faculty of Mathematics and Natural Sciences, Eberhard-Karls University Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| |
Collapse
|
6
|
Curto SG, de las Heras LA, Esteruelas MA, Oliván M, Oñate E. C(sp3)–Cl Bond Activation Promoted by a POP-Pincer Rhodium(I) Complex. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00409] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Sheila G. Curto
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)-Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Laura A. de las Heras
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)-Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Miguel A. Esteruelas
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)-Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Montserrat Oliván
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)-Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Enrique Oñate
- Departamento de Química Inorgánica-Instituto de Síntesis Química y Catálisis Homogénea (ISQCH)-Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| |
Collapse
|