# Poly(vinyl chloride) Dechlorination Catalyzed by Zirconium

Adrien Normand, Yue Wu, Tiffanie Régnier, Paul Fleurat-Lessard, Yoann Rousselin, Benjamin Théron, Pierre Le Gendre, Mariolino Carta

► To cite this version:

Adrien Normand, Yue Wu, Tiffanie Régnier, Paul Fleurat-Lessard, Yoann Rousselin, et al., Poly(vinyl chloride) Dechlorination Catalyzed by Zirconium. Chemistry - A European Journal, 2024, 30 (21), pp.e202304005. 10.1002/chem.202304005. hal-04729589

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# Poly(vinyl chloride) Dechlorination Catalyzed by Zirconium

Adrien T. Normand,*[a] Yue Wu,[b] Tiffanie Régnier,[c] Paul Fleurat-Lessard,[a] Yoann Rousselin,[c] Benjamin Théron,[a] Pierre Le Gendre,[a] and Mariolino Carta[b]

Poly(vinyl chloride) undergoes dechlorination in the presence of triethylsilane (Et₃SiH) and a catalytic amount of [Cp₂Zr-(NPh₂)][CH₃B(C₆F₅)₃] (1b) at 40–80 °C, with up to 91% efficiency. Stoichiometric reactivity studies conducted on cyclohexyl chloride as a model suggest that 1b dechlorinates PVC by initial

chloride abstraction, followed by hydride transfer to the cationic PVC chain from Et₃SiH. Consumer items such as pipe fitting, vinyl disc or electric cable insulation undergo either dechlorination or hydrosilylation of the carbonyl-containing copolymer (polyvinyl acetate) or plasticizer (phthalate).

## Introduction

The exponentially growing production of plastics, together with the multifaceted challenges associated with their mechanical recycling on industrial scale, have resulted in a colossal – yet increasingly dispersed – amount of plastic solid waste (PSW) in the environment.[1] As one of the main classes of thermoplastics, Poly(vinyl chloride) (PVC) is also one of the most problematic from a waste management perspective.[2] Firstly, it releases copious amounts (>50% mass balance) of corrosive hydrochloric acid upon thermal degradation.[3] Secondly, formulated PVC frequently contains so-called legacy additives (e.g. phthalate plasticizers or cadmium, lead and tin stabilizers),[4] which threaten the economic and environmental viability of recycling processes.[5] Both of these features open up opportunities for the chemical recycling/upcycling of PVC and its additives.[6]

Hydrodechlorination (HDC, Scheme 1) of PVC has been known since the 1950s, when Cotman reported its reduction with LiAlH₄ in refluxing THF.[7] Although this reaction is mainly interesting for analytical purposes (i.e. the determination of branching),[8] a modified version using milder and safer silanes has recently attracted attention in the context of plastic waste management.[9] Alternatively, tandem dehydrochlorination (DHC)/hydrogenation under H₂ pressure yields similar polyethylene-like (PE) polymers.[10] However, these recently dis-

<figure><img src="image_3.png" /><figcaption>Dehydrochlorination (DHC) / Hydrogenation</figcaption></figure>

**State-of-the-art**
Precious Metals (Ir, Rh, Pt)

Stoichiometric Additive
(Tandem DHC)

High Temperatures
(110-180 °C)

**This work**
Non-Precious Metal (Zr)

No Additives

Moderate Temperatures
(40-80 °C)

<caption>Scheme 1. The catalytic dechlorination of PVC by hydrogen donors.</caption>

closed methodologies rely on precious metal catalysts (Rh, Ir, Pt) as well as elevated temperatures (110–200 °C). Moreover, in the case of tandem DHC/hydrogenation, the use of stoichiometric amounts of ionic liquids or bases is required.[10]

An intriguing variation of HDC that circumvents the use of precious metals – using the triphenylcarbenium cation as precatalyst instead – has recently been reported by Fieser: in this case, Friedel-Crafts reaction of PVC with the aromatic solvent at 110 °C generates a poly(ethylene-co-styrene) polymer, along with H₂.[11] Unfortunately, this methodology involves the generation of a silane-dependent active catalyst ("Et₃Si⁺"), which inevitably restricts its potential for catalyst optimization, and hence, further industrial development.

In light of the above, it would be of great interest to develop optimizable dechlorination catalysts, based on non-precious metals, which would operate under mild conditions. A successful strategy for the dehalogenation of organic com-

[a] Dr. A. T. Normand, Prof. P. Fleurat-Lessard, B. Théron, Prof. P. Le Gendre
Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB)
9 avenue Alain Savary, 21078 Dijon Cedex (France)
E-mail: Adrien.normand@u-bourgogne.fr

[b] Y. Wu, Dr. M. Carta
Department of Chemistry, Faculty of Science and Engineering
Swansea University, Singleton Park, SA2 8 PP Swansea (Wales)

[c] T. Régnier, Dr. Y. Rousselin
Plateforme d'Analyse de l'Institut de Chimie Moléculaire de l'Université de
Bourgogne (PACSMUB)
9 avenue Alain Savary, 21078 Dijon Cedex (France)

<figure><img src="image_4.png" /></figure>

Supporting information for this article is available on the WWW under
https://doi.org/10.1002/chem.202304005

<figure><img src="image_5.png" /></figure>

© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
<figure><img src="image_6.png" /></figure>

<figure><img src="image_7.png" /><figcaption>**Figure 1.** Cationic group 4 amidometallocene complexes tested in this study.</figcaption></figure>

pounds consists in using strongly Lewis acidic catalysts in the presence of silanes.[12] Following this approach, Group 4 metals have had some success,[13] suggesting that PVC could also be reduced in this way. In the context of catalysis applied to waste management, the higher abundance of Ti and Zr in comparison to precious metals is a key advantage.[14]

During the past decade, we have investigated the catalytic properties of cationic group 4 amidometallocene complexes (such as **1a** and **1b**, Figure 1) in hydrogenation,[15] dehydrocoupling,[15b] and hydrosilylation reactions.[16] It occurred to us that the high Lewis acidity of these species makes them ideal candidates for the dehalogenation of various substrates, including PVC. In this contribution, we show that Zr complex **1b** indeed converts PVC into a PE-like polymer under mild conditions, and hence report the proof-of-concept of PVC dechlorination with a non-precious metal under mild conditions.

## Results and Discussion

As a model for PVC dechlorination, we initially tested the HDC performance of complex **1b** against chlorocyclohexane, using 2 eq of Et₃SiH. After 72 h at 40 °C, a modest conversion (24% total) to cyclohexane (HDC product) and cyclohexene (DHC product) was observed, which translate into a reasonable Turnover Number of 480 (Scheme 2). The presence of Et₃SiCl was also established by GCMS analysis and quantified by ¹H NMR spectroscopy (26%, in agreement with the 24% combined NMR yield of cyclohexane and cyclohexene; see the Supporting Information, Figures S1 and S2).

Interestingly, while **1b** does not react with Et₃SiH alone,[16] mixing **1b** in C₆D₅Br with 3 eq of chlorocyclohexane alone immediately afforded a complex mixture in which both HDC and HDC products were observed. A new signal was observed in the Cp region of the ¹H NMR spectrum, suggesting the clean

<figure><img src="image_8.png" /><figcaption>**Scheme 2.** Catalytic reduction of chlorocyclohexane.</figcaption></figure>

formation of a single Zr species. Additionally, slightly shifted diphenylamine signals were observed, and the ¹¹B{¹H} and ¹⁹F {¹H} spectra indicated that the CH₃B(C₆F₅)₃⁻ anion had evolved into a complex mixture (Figures S3–S5). In the absence of silane, it seems likely that the borate anion acts as a source of hydride to generate the HDC product. Taken together, these observations strongly suggest that the model reaction of PVC dechlorination (Scheme 2) proceeds via initial chloride abstraction by **1b**, followed by hydride transfer from Et₃SiH (HDC) or proton elimination from C₆H₁₁⁺ (DHC) (Scheme 3).

In support of this mechanism, DFT calculations at the B3PW91 level of theory show that Cl abstraction by Et₃Si⁺ is much more favourable for Cp₂Zr(Cl)NPh₂ (Δₐ,G⁰ = -20.7 kcal·mol⁻¹) than for chlorocyclohexane (Δₐ,G⁰ = -11.1 kcal·mol⁻¹). Therefore, the possibility that **1b** merely acts as an initiator to generate Et₃Si⁺ as the active catalyst (orange arrows, Scheme 3) can be excluded, since the formation of Et₃SiCl is more favourable from the zirconium intermediate (blue arrows).

Note that, as shown in scheme 3, the eliminated proton could react with Et₃SiH, generating H₂ and Et₃Si⁺; thus, since **1b** is an active olefin hydrogenation catalyst, cyclohexane (HDC) could also be generated by hydrogenation of cyclohexene (DHC).[15a]

Encouraged by these preliminary results, we then turned our attention to the reduction of PVC (Table 1). Unformulated PVC powder (analytical standard, Mw = 85000, Mn = 40000) was heated at 40 °C for 16–24 h in C₆H₅Br in the presence of Et₃SiH (2 eq/monomer unit) and 1 mol% of catalyst. The reaction mixture was precipitated from MeOH and the obtained polymers were analysed by ¹H NMR and IR spectroscopies and elemental analysis. The extent of dechlorination, established by elemental analysis, should be taken as a lower estimate (see the Supporting Information).

We first tested the performance of various precatalysts (entries 1–6). Under the chosen experimental conditions, Ti complex **1a** afforded an insoluble, poorly dechlorinated poly-

<figure><img src="image_9.png" /><figcaption>**Scheme 3.** Proposed mechanism for the dechlorination of cyclohexane (model for PVC).</figcaption></figure>
<figure><img src="image_10.png" /></figure>

<table><caption>**Table 1.** Catalytic reduction of PVC catalyzed by Lewis acids.</caption><thead><tr><th>Entry</th><th>Catalyst</th><th>Aspect</th><th>Solubility in THF</th><th>Yield (mg)<sup>[a]</sup></th><th>%<sup>dechi</sup><sub>[a]</sub></th></tr></thead><tbody><tr><td>1<sup>[b]</sup></td><td><b>1a</b></td><td>Powder</td><td>No</td><td>67</td><td>&gt; 14</td></tr><tr><td>2<sup>[b]</sup></td><td><b>1b</b></td><td>Sticky solid</td><td>Partial</td><td>77</td><td>&gt; 75</td></tr><tr><td>3</td><td>Cp<sub>2</sub>ZrCl<sub>2</sub> / "Et<sub>3</sub>Si<sup>+</sup>"</td><td>Powder</td><td>Poor</td><td>61</td><td>&gt; 75</td></tr><tr><td>4</td><td>"Ph<sub>3</sub>C<sup>+</sup>"</td><td>Powder</td><td>Poor</td><td>80</td><td>&gt; 75</td></tr><tr><td>5</td><td>"Et<sub>3</sub>Si<sup>+</sup>"</td><td>Powder</td><td>Poor</td><td>87</td><td>&gt; 70</td></tr><tr><td>6</td><td>B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub></td><td>Powder</td><td>Yes</td><td>129<sup>[c]</sup></td><td>&gt; 2</td></tr></tbody></table>

**Reagents and conditions.**: 125 mg PVC (2 mmol monomer), 465 mg Et<sub>3</sub>SiH (4 mmol), 1 mol% catalyst, 2 mL C<sub>6</sub>H<sub>5</sub>Br, 40 °C, 24 h. "Et<sub>3</sub>Si<sup>+</sup>": [(Et<sub>3</sub>Si)<sub>2</sub>H][B-(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]. "Ph<sub>3</sub>C<sup>+</sup>": [Ph<sub>3</sub>C][B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]. <sup>[a]</sup>: average of two runs <sup>[b]</sup>: 16 h. <sup>[c]</sup>: one run contained residual MeOH.

mer (> 14%, entry 1). By contrast, **1b** was much more efficient and reached > 75% dechlorination and much improved solubility (entry 2). The use of Cp<sub>2</sub>ZrCl<sub>2</sub>, in conjunction with a silylium-based chloride abstractor [(Et<sub>3</sub>Si)<sub>2</sub>H][B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]<sup>[17]</sup> was equally effective (> 75%, entry 3); however the obtained polymer was poorly soluble in organic solvents, which could be due to a high degree of cross-linking. We also tested the silylium reagent and its triphenylcarbenium precursor alone, and they both gave similarly good results, as expected (entries 4 and 5). Again, hardly soluble polymers were obtained, consistent with the notion that Et<sub>3</sub>Si<sup>+</sup> is not the active catalyst when **1b** is used as a precatalyst. Also, entry 4 stands in contrast with the results reported by Fieser using BTX (Benzene, Toluene, Xylenes) solvents.<sup>[11]</sup>

A possible explanation is that in our case, C<sub>6</sub>H<sub>5</sub>Br is too electron-poor to engage in Friedel-Crafts reactions with the cationic PVC intermediate obtained after chloride abstraction by Et<sub>3</sub>Si<sup>+</sup>, and that cross-linking events occur instead, causing solubility issues. Interestingly, the use of B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>, another strong Lewis acid, was ineffective (entry 6).

We then optimized reaction conditions by varying the reaction time, catalyst loading, temperature and silane source (Table S1, entries 7–14). From these experiments, we conclude that a 1 mol% loading of **1b** at 40–60 °C in the presence of Et<sub>3</sub>SiH in C<sub>6</sub>H<sub>5</sub>Br for at least 24 h are optimal conditions. Notably, we note a slight erosion of dechlorination activity at 80 °C, which suggests that catalyst deactivation starts to become competitive with dechlorination at higher temperatures. Interestingly, the reaction could also be performed under solventless conditions, albeit at 120 °C (Figures S24–S26).

Using the optimized conditions, we conducted further experiments on 500 mg of PVC (Table S2). The polymer obtained at 40 °C (P<sup>40</sup>) is a sticky powder with > 82% dechlorination, whereas the polymer obtained at 60 °C (P<sup>60</sup>) is an elastic gum with > 91% dechlorination. These polymers

were further characterized with a range of analytical techniques: ¹H and ¹³C NMR spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, powder X-ray diffraction, Gel Permutation Chromatography (GPC), thermogravimetric analysis (TGA), and Scanning Electron Microscopy (SEM).

The FTIR spectra of P<sup>40</sup> and P<sup>60</sup> are shown in Figure 2, along with those of the starting material, and a sample of High Density Polyethylene. The dechlorination of PVC is evident from the disappearance of the absorptions (pink boxes) corresponding to C–Cl stretching (603 cm<sup>−1</sup>) and Cl–C–H bending modes (1234 cm<sup>−1</sup>), along with the appearance of polyethylene-like absorptions (blue boxes) corresponding to C–H stretching (ν<sub>H</sub>, 2852 cm<sup>−1</sup>; ν<sub>as</sub>, 2919 cm<sup>−1</sup>) and H–C–H bending modes (724 and 1457 cm<sup>−1</sup>). In addition, a weak absorption (grey box) can be observed at 1654 cm<sup>−1</sup> which we attribute to the presence of a small number of C=C bonds resulting from DHC.<sup>[18]</sup>

The NMR spectra recorded at 298 K in d<sub>8</sub>-THF (Figure 3 for P<sup>60</sup>, and S13–S18) lead us to the same conclusions.<sup>[19]</sup> In the ¹H NMR spectra, we observe the almost complete disappearance of signals at 4.65–4.30 ppm (CHCl) and 2.45–2.05 ppm (CH<sub>2</sub>CHCl) regions (pink boxes, Figure 3), along with the appearance of a strong polyethylene-like CH<sub>2</sub> signal at 1.42–1.15 ppm (blue box) that correlates with a ¹³C signal at 30.5 ppm in the HSQC spectrum (Figure 3, top left). A set of signals of low intensity at 5.43–5.32 ppm suggest the presence of trace amounts of C=C moieties (grey box). This is corroborated by the ¹³C{¹H}, DEPT 90 and DEPT 135 spectra (Figures S30 and S32), with the presence of a low-intensity CH signal at 130.6 ppm. A close inspection of the aliphatic region of these spectra also reveals the presence of several additional CH<sub>2</sub> units and CH branch points, and one terminal CH<sub>3</sub> unit, consistent with the description of P<sup>60</sup> as a partially chlorinated, cross-linked PE-like polymer (Figure 4).<sup>[20]</sup>

Also consistent with this view, the GPC chromatograms (Figures S34–S36 and Table S3) indicate that the relatively narrow-dispersed PVC D=2.1) has undergone both extensive chain scission and growth (D=28–29), presumably by cross-linking events. This suggests a mechanism (Scheme 4) in which cationic PVC chains are generated, from which several events can occur: hydride transfer from Et<sub>3</sub>SiH (HDC), H<sup>+</sup> elimination (DHC), β-scission (chain scission),<sup>[21]</sup> and alkene addition (cross-linking).<sup>[10a]</sup> At the moment, it is not clear whether the small number of unsaturations observed by FTIR and NMR spectroscopies is due to preferential HDC over DHC, tandem DHC-hydrogenation, or alkene addition.

The TGA curves of P<sup>40</sup> and P<sup>60</sup> show the considerable enhancement of thermal stability compared to PVC: the 50% mass loss threshold is reached at 460–470 °C, versus 325 °C for PVC (Figure 5). This is an expected result, given that most of the mass loss in PVC is caused by HCl release.<sup>[22]</sup>

The DSC curves of P<sup>40</sup> and P<sup>60</sup> show no melting/crystallization events in the −20 to 190 °C range after the first heating ramp (Figure S38), in contrast to the behaviour of PE samples which usually melt at 110–130 °C.<sup>[23]</sup> These results indicate that P<sup>40</sup> and P<sup>60</sup> are amorphous, and this was confirmed by the results of powder X-ray diffraction analysis (Figure S39).<sup>[24]</sup>
<figure><img src="image_11.png" /></figure>

<figure><img src="image_12.png" /><figcaption>**Figure 2.** FTIR spectra (ATR) of dechlorinated polymers.</figcaption></figure>

<figure><img src="image_13.png" /><figcaption>**Scheme 4.** Proposed mechanism for HDC, DHC, chain scission, and cross-linking.</figcaption></figure>
<figure><img src="image_14.png" /></figure>

<figure><img src="image_15.png" /><figcaption>**Figure 3.** ¹H NMR and ¹H-¹³C HSQC spectra of PVC and P⁶⁰ (d₈-THF, 298 K, 600 MHz). *: THF signal. §: Water signal.</figcaption></figure>

Finally, SEM was used in order to compare the morphology of dechlorinated polymers versus native PVC (Figure 6). It is clear that the beads structure of the particles of PVC has been smoothened upon dechlorination.

Given the encouraging results obtained with unformulated PVC,[25] we turned our attention to PVC-containing consumer items which are likely to be found in PSW: a 10" 33⅓ RPM vinyl disc (LP), the insulation of a grounding conductor (Wire) and a plumbing fitting (Fitting). In order to study the influence of additives on dechlorination, we performed a simple deformation procedure aimed at removing either soluble or insoluble additives.[4a] This deformation procedure is schematized in Scheme 5 (page 7).

From each raw consumer item (Item), we obtained:

- a reprecipitated fraction (Item®) free of soluble additives such as phthalate plasticizers, phosphite flame retardants, etc.

- a centrifugated fraction (ItemC) free of insoluble additives such as calcium stearate or laurate stablizers, calcium carbonate filler, carbon black pigment, etc.

We then analysed the raw and (partially) unformulated items by ¹H NMR and FTIR spectroscopies (Figures S41–S46).

<figure><img src="image_16.png" /><figcaption>**Scheme 5.** Deformation of PVC-containing consumer items. Fractions in red were discarded, those in green were tested for catalytic dechlorination.</figcaption></figure>

For LP and its derivatives, apart from the removal of carbon black in LP®, no obvious changes were observed. In particular, the polyvinylacetate (PVA) copolymer was always observed, as evidenced by the presence of a C=O absorption band at 1734 cm⁻¹ in the FTIR spectra (Figure S41).

For Wire and its derivatives, reprecipitation from MeOH removed the phthalate plasticizer, which was observed by GCMS analysis of the filtrate (Figure S47). This observation was corroborated by the comparison of the FTIR and ¹H NMR spectra of Wire, Wire® and WireC (Figures S42 and S45).
<figure><img src="image_17.png" /></figure>

<figure><img src="image_18.png" /><figcaption>**Figure 4.** DEPT 90 and 135 spectra (d<sub>8</sub>-THF, 151 MHz, 298 K) of P<sup>60</sup> (aliphatic region). *: THF signal; Blue boxes: CH branch points; green boxes: CH<sub>2</sub> units; red box: CH<sub>3</sub> end group.</figcaption></figure>

<figure><img src="image_19.png" /><figcaption>**Figure 5.** TGA curves of dechlorinated polymers.</figcaption></figure>

For **Fitting** and its derivatives, no obvious spectroscopic changes were noted, although some grey insoluble material was removed during centrifugation.

These materials were then treated with Et<sub>3</sub>SiH in the presence of **1b** at 80°C for 72 h, (see the Supporting

Information for details). The solid products obtained after workup were analysed spectroscopically by FTIR (Figures S51-S59) and ¹H NMR (Figures S60-S68), and by elemental analysis (Table S5 and Figures S48-S50).

Interestingly, **LP** and its derivatives underwent complete loss of the ester function of PVA (this is especially visible in the IR spectra, Figures S51-S53), in line with the known ester hydrosilylation activity of **1b**;[16] however, no significant PVC reduction was observed.

For **Wire** and its derivatives, no significant changes were observed when the effect of the workup procedure was taken into account (Figures S49 and S50), indicating that both soluble and insoluble additives poison the catalyst. Therefore, more studies are needed in order to identify precisely which additives are responsible for the loss of dechlorination activity. Importantly, however, ¹H NMR spectroscopy and GCMS analysis of the filtrate obtained after workup in the case of **Wire** and **Wire**<sup>C</sup> revealed the absence of phthalate (Figures S69-S72). It is unclear at this stage why carbonyl hydrosilylation is not affected by the presence of additives, while dechlorination is inhibited; we surmise that different active catalysts are involved in each manifold. Still, the possibility of generating phthalate-free PVC through hydrosilylation is intriguing, since the
<figure><img src="image_20.png" /></figure>

<figure><img src="image_21.png" /><figcaption>**Figure 6.** SEM (micrographs x200, x1300 and x3500 magnification) of PVC (top) and P⁶⁰ (bottom).</figcaption></figure>

presence of trace phthalates in recycled PVC is highly problem-
atic – as illustrated by the demise of the VinyLoop process.[5]

Finally, **Fitting** and its derivatives underwent notable PVC dechlorination; in the case of **Fitting**, a combined carbon + hydrogen content of 59.55% could be reached, versus 43.10% for the starting material. For **Fitting**<sup>R</sup> and **Fitting**<sup>C</sup>, dechlorination was even more efficient: 63.06 vs 42.28%, and 80.57 vs 46.88%, respectively (Table S5)

Conclusions

In conclusion, we have reported the proof-of-concept of a PVC dechlorination methodology based on a commonly available silane reagent, and a non-precious metal (Zr) catalyst operating under mild conditions. While not always immune to poisoning by the additives commonly encountered in PVC-containing consumer items, this catalyst is still able to promote the hydrosilylation of ester functions – a particularly interesting feature in the case of phthalates. Future studies will focus on investigating *i*) the mechanism of these transformations, *ii*) the use of other electrophilic group 4 metal catalysts in PVC dechlorination, with a view to control the chain-modifying events (cross-linking, chain growth and scission) and *iii*) possible applications of the dechlorinated materials, depending on their mechanical properties, calorific value,[26] etc.

**Supporting Information Summary**

The authors have cited additional references within the
Supporting Information.[27] The supporting information includes

NMR and FTIR spectra, GCMS and SEC chromatograms, TGA and
DSC curves, SEM micrographs, and computational details.

Acknowledgements

We thank Ms Marie-Laure Leonard for running additional DSC measurements during the revision of the manuscript. Calculations were performed using HPC resources from DSI-CCUB (Université de Bourgogne). MC and YW gratefully acknowledge funding from the Engineering and Physical Sciences Research Council (EPSRC), Grant number: EP/T007362/1 "Novel polymers of intrinsic microporosity for heterogeneous base-catalysed reactions (HBC-PIMs)".

Conflict of Interests

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available in
the supplementary material of this article.

Keywords: Earth-abundant metals • PVC • Silanes • Dechlorination

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