Upcycling of halogenated polymers to obtain value added products

Abstract

The present invention relates to process for halogenation of aromatic and / or heteroaromatic compounds with polymers derived from dihalogenated monomers or plastic waste products thereof as halide source under additive-free electrochemical conditions working in an undivided cell to produce halogenated aromatic and / or heteroaromatic compounds and / or dehalogenated polymers in a batch mode and / or a continuous flow mode. Further, present invention provides a process for the preparation of value-added products from the dehalogenated polymers by deconstructing and / or depolymerizing via cross-metathesis and other reactions.

Description

[0001] UPCYCLING OF HALOGENATED POLYMERS TO OBTAIN VALUE-ADDED PRODUCTS

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a simultaneous process for the halogenation of an aromatic and / or heteroaromatic compound and dehalogenation of polymer material derived from dihalogenated monomer. Particularly, the present invention relates to a process of halogenation of the aromatic and / or heteroaromatic compounds with polymers derived from dihalogenated monomers or plastic waste products thereof as halide source under additive-free electrochemical conditions working in an undivided cell to produce halogenated aromatic and / or heteroaromatic compounds and / or dehalogenated polymers.

[0004] More particularly, the present invention relates to a process for the preparation of value- added products from the dehalogenated polymers by deconstructing and / or depolymerizing via cross-metathesis and other reactions.

[0005] BACKGROUND OF THE INVENTION

[0006] Plastic material has become essential due to their extensive uses, contributing significantly to the global economy. The global production of plastics soared to 390.7 million tonnes in 2021. Their chemical stability, providing durability and protection against damage, renders them challenging to degrade. As a consequence, discarded plastics accumulate in landfills or are incinerated for energy, resulting in environmental harm. Urgent action is needed to recycle or upcycle waste plastics to establish a circular economy. However, plastic recycling involves multiple steps — collecting, sorting, cleaning, shredding, and processing — that can be costly compared to producing new plastics from fossil-based materials. Additionally, products derived from recycled plastics often exhibit lower quality than those from virgin plastics, and there are limitations to the number of times plastics can be recycled. With a recycling rate of only 9.9% in 2021, it remains far below the staggering annual production of plastics.

[0007] The early stages of plastic upcycling display vast potential. Researchers must delve into understanding the chemical modification and degradation mechanisms of polymers. Altering polymers’ functionalities transforms material properties and enables deconstruction into sought-after monomers and molecules. Presently, polyethylene terephthalate (PET) stands as one of the most upcycled plastics, owed to its susceptible ester group, easily cleaved through solvolysis or enzymatic processes. However, polyolefins lead in production among all polymers. Despite lower production, halogenated polymers pose extreme challenges for recycling or upcycling due to the generation of corrosive hydrogen halides, potentially contaminating catalysts. These polymers find use in food and medical packaging due to their exceptional barrier properties against oxygen and moisture, especially within multi-layered plastics (MLP). Even a minimal amount of halogenated polymer complicates the deconstruction of other polymers. Given the pivotal role of additives in plastics, chemical transformations must be resilient enough to operate in their presence — a critical challenge in plastic upcycling.

[0008] Reference may be made to the Journal “Science. 2022 Sep 30:377(6614): 1561-1566” which discloses a breakthrough in degrading polyethylene and polypropylene using catalysts like ruthenium, iridium, and palladium.

[0009] Reference may be made to the Journal “Science. 2023 Feb 24;379(6634):807-811” which discloses a novel method, leveraging ionic liquid, to break down polyethylene and polypropylene into isoalkanes (C6 to CIO) at reduced temperatures through alkylation cracking. Current chemical techniques for breaking down polyolefins typically rely on costly precious metal catalysts such as ruthenium, iridium, rhodium, and palladium, alongside employing rigorous reaction conditions. These factors render the existing methods less environmentally and economically viable.

[0010] Reference may be made to the Journal “Nature Chemistry, Volume 15, February 2023, 222-229” which discloses the reaction works in the absence of Di(2-ethylhexyl) phthlate (or DEHP), to have a synthetically useful method the scope was performed in a divided cell in the presence of DEHP. The absence of DEHP (di (2- ethylhexyl) phthalate) gives a yield upto 88%.

[0011] In the present invention, a different electrolyte tetrabutylammonium hexafluorophosphate (THF) is used and the method works efficiently with other substrates without DEHP. Furthermore, this is the first example where polyvinylidene chloride (PVDC) is subjected as a chlorination reagent in an undivided cell in the absence of any mediator such as DEHP. However, the method works with only 4 equiv. of PVDC giving the chlorination product with full conversion. The present invention reports the highest dechlorination ever achieved in any electrochemical method. The earlier reports did not talk about the fate of the polymer after dehydrochlorination. Whereas, the present invention has shown a viable method for depolymerization.

[0012] Reference may be made to the Journal “ChemPlusChem 2023, 88, e202300184” which discloses a method of degradation of PVC by sequential dehydrochlorination and olefin metathesis using Olefin metathesis performed using Z-l,4-diacetoxy-2-butene (DAB), DPVCx and Grubbs 2 catalyst in refluxing dichloromethane (DCM). Following olefin metathesis at many double bond sites, the expected products are PVC oligomers (from the non-eliminated segments) and a mixture of different lengths polyenes. However, this protocol does not work if ethylene is used instead of DAB. Therefore, it is not obvious that an ethylene metathesis is same as reported here. One has to think beyond this prior art to come up with a different process to break down dPVC to small chlorinated molecules.

[0013] There have been reports on the deconstruction of polyvinyl chloride (PVC) through basemediated dehydrochlorination, followed by metathesis. This process involves the use of potent potassium hydroxide as a strong base, resulting in the formation of potassium chloride as a byproduct.

[0014] Reference may be made to the Journal “Chem. Sci., 2024, 15, 5802-5813” which discloses a chlorination technique for aromatic and heteroaromatic compounds using discarded PVC as a chlorinating agent. The plasticizer DEHP facilitates this reaction as a mediator, necessitating a rather intricate divided cell setup. Notably, the characterization of the polymer's structure post-dechlorination remains insufficiently explored. Halogenated compounds are notably significant due to their wide-ranging applications in agrochemicals, pharmaceuticals, material sciences, and as pivotal constituents in various products.

[0015] Hence, there remains an urgent need to develop improved, efficient, cost-effective, and environmentally friendly halogenation methods that are simple to scale up. Therefore, the present invention discloses a chlorination method that works without any additive in operationally simple undivided cells. The process was replicated using PVDC instead of PVC for the identical chlorination reaction, yielding even more favourable results. Further examination is ongoing concerning the residual fluorinated polymers.

[0016] OBJECTS OF THE INVENTION

[0017] Main object of the present invention is to provide a simultaneous process for the halogenation of an aromatic and / or heteroaromatic compound and dehalogenation of polymer material derived from dihalogenated monomer.

[0018] Another object of the present invention is to provide an efficient, cost-effective, and environmentally friendly process of halogenation of aromatic and / or heteroaromatic compounds.

[0019] Yet another object of the present invention is to provide a process for chlorination of phenetole using materials selected from a group consisting PVDC and PVC blister film, PVDC-PO multilayer food plastic, heat stabilizer integrated with PVDC or combinations thereof.

[0020] Yet another object of the present invention is to provide a process for dehalogenation of polymers such as but not limited to PVDC and combinations of PVC and PVDC thereof under electrochemical conditions, by utilizing excess arenes or aromatic compounds as the limiting reagent.

[0021] Yet another object of the present invention is to provide a continuous flow electrochemical method for PVC / PVDC recycling.

[0022] Still another object of the invention is to provide a process for the preparation of value- added products such as butadiene, ethylene, propylene, hexene, octene, decene, dodecene, polyacetylene, etc. from the dehalogenated polymers by deconstructing and / or depolymerizing via cross-metathesis and other reactions.

[0023] BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Fig. 1 represents1H NMR spectrum of reaction (crude) mixture in CDCI3.

[0025] Fig. 2 represents GC-MS chromatogram of cross-metathesis reaction. Fig. 3 (A to C) represents mass spectra of possible structures of metathesis products and their mass.

[0026] Fig. 4 represents GPC analysis of dechlorinated polyvinyl chloride (dPVC) before and after metathesis.

[0027] Fig. 5 represents GPC analysis of soluble fraction isolated after metathesis reaction.

[0028] Fig. 6 (A and B) represents thermogravimetric analysis (TGA) of PVDC and dechlorinated PVDC (dPVDC).

[0029] Fig. 7 represents the raman spectra of dechlorinated PVDC (dPVDC).

[0030] Fig. 8 represents electro-flow cell for chlorination using PVDC.

[0031] Fig. 9 represents chlorinated aromatic and heteroaromatic compounds.

[0032] Fig. 10 represents the chlorination of phenetole using PVC.

[0033] Fig. 11 represents the chlorination of phenetole using commercially available PVC-tubing.

[0034] Fig. 12 represents the chlorination of phenetole using PVDC powder.

[0035] Fig. 13 represents the chlorination of phenetole using PVDC / PVC blister film.

[0036] Fig. 14 represents the chlorination of phenetole using PVDC-PO multilayer food plastic.

[0037] Fig. 15 represents the chlorination of phenetole using PVDC with heat stabilizer.

[0038] Fig. 16 represents the chlorination of phenylpyrazole in continuous flow method.

[0039] Fig. 17 represents the electrochemical deconstruction of PVC and PVDC.

[0040] Fig. 18 represents the general procedure for the metathesis of dechlorinated PVC (dPVC) with ethylene.

[0041] Fig. 19 represents the dechlorination of PVDC by repeated chlorine removal. SUMMARY OF THE INVENTION

[0042] Accordingly, present invention provides a simultaneous process for the halogenation of an aromatic and / or heteroaromatic compound and dehalogenation of polymer material derived from dihalogenated monomer, wherein the process comprising the steps of: i. reacting the aromatic and / or heteroaromatic compound with the polymer material derived from dihalogenated monomer as a halide source under an additive-free electrochemical conditions in an undivided cell to obtain the halogenated aromatic and / or heteroaromatic compound and dehalogenated polymer.

[0043] In an embodiment of the present invention, said process is conducted in batch and / or in continuous flow mode.

[0044] In another embodiment of the present invention, said aromatic and / or heteroaromatic compound is selected from the group consisting of (un)substituted aryl, (un)substituted heteroaryl, wherein substituted group is selected form alkyl, alkoxy, aryloxy, hydroxyl, ester, free amine, and sulfide hydroxyl.

[0045] In yet another embodiment of the present invention, said polymer material derived from dihalogenated monomer as a halide source is selected from the group consisting of PVDC blister film, PVC / PVDC blister film, PVDC-PO multilayer food plastic, heat stabilizer integrated with PVDC or combination thereof.

[0046] In yet another embodiment of the present invention, said halogenated aromatic and / or heteroaromatic compound is selected from the group consisting of: i. l-Chloro-4-ethoxybenzene (2a); ii. l-Chloro-4-methoxybenzene (2b); iii. 4-Chloro-l,2-dimethoxybenzene (2c) and l,2-Dichloro-4,5- dimethoxybenzene (2c'); iv. 2-Chloro-l,3,5-triethylbenzene (2d); v. 2,4-Dichloro-l,3,5-trimethoxybenzene (2e') and 2-Chloro-l,3,5- trimethoxybenzene (2e); vi. Methyl 5-chloro-2-methoxybenzoate (2f); vii. l-(3-Chloro-lH-indol-l-yl)-2,2-dimethylpropan-l-one (2g); viii. 1 -(3 -Chloro- lH-indol-l-yl)ethan-l -one (2h); ix. Ethyl 3-chloro-lH-indole-2-carboxylate (2i); x. Ethyl 3,5-dichloro-lH-indole-2-carboxylate (2j); xi. 4-Chloro-l -phenyl- IH-pyrazole (2k); xii. 4-Chloro-3-phenyl-5-(trifluoromethyl)-lH-pyrazole (21); xiii. 2-Chloro-5-phenylthiophene (2m); xiv. 3 -Chlorobenzo [b] thiophene (2n); xv. 2-Chloro-3-methylbenzo[b]thiophene (2o); and xvi. 4,5-Dichloro-l-phenyl-lH-imidazole (2p).

[0047] In yet another embodiment of the present invention, the additive-free electrochemical conditions comprise polymer derived from dihalogenated monomer in a range of 2-8 equivalents, a constant current is kept in the range of 10-20 mA, alternating polarity is kept at every 15-30 minutes and a time period of the process is in the range of 16-24 hours.

[0048] In yet another embodiment of the present invention, yield of the halogenated aromatic and / or heteroaromatic compounds is in the range of 70-90%.

[0049] In yet another embodiment, present invention provides a process for the preparation of value-added product by deconstructing and / or depolymerizing the dehalogenated polymer via alkene-mediated cross-metathesis reaction, wherein said process comprising the steps of: a. charging the dechlorinated polymer and metathesis catalyst in a reaction vessel followed by pre-cooling under vacuum; wherein metathesis catalyst used is Grubbs II catalyst; b. introducing a solvent into the reaction vessel of step a) under inert atmosphere and transferring the vessel into autoclave and purging with ethylene gas three times with 20 to 40 bar pressure wherein the solvent used is dry THF; c. pressurizing the autoclave with 20 to 30 bar ethylene gas at a temperature in the range of 75-80°C for a time period of 2-2.5 hr; and d. cooling the autoclave at a temperature in the range of 25-35°C and releasing the ethylene pressure followed by adding a solvent to obtain the value-added product.

[0050] In yet another embodiment of the present invention, said value added product is selected from the group consisting of butadiene, ethylene, propylene, hexene, octene, decene, dodecene, and polyacetylene or combinations thereof and dehalogenated polymer is selected from the group consisting of dechlorinated PVC, and PVDC polymer or combinations thereof.

[0051] In yet another embodiment, present invention provides a continuous flow process for the halogenation of aromatic and / or heteroaromatic compounds using halogenated polymer materials selected from a group consisting PVC, PVDC / PVC blister film, PVDC-PO multilayer food plastic, heat stabilizer integrated with PVDC or combinations thereof comprises the steps of: a) preparing a stock solution of reaction mixture consisting of aromatic and / or heteroaromatic compound, tetrabutylammonium tetrafluoroborate (nBu4NBF4), halogenated polymer material in a polar solvent; b) providing an electrochemical cell and applying current to the electrochemical cell by using a power-supply unit; c) passing the stock solution as prepared at step a) through the electrochemical cell at a flow rate of 0.6- 1.0 mL / min at 1.0 A current; d) passing the solution of step a) or c) through the electrochemical cell at a flow rate of 0.6- 1.0 mL / min at 2.0 A current; e) collecting the solution from step d) followed by adding in a solvent at temperature in the range of 0-2°C and filtering to obtain a filtrate; f) concentrating the filtrate of step e) under reduced pressure followed by diluting the concentrated mixture with extraction solvent to obtain a bilayer aqueous- organic mixture; g) washing the organic layer obtained in step f) with water for at least three times followed by extracting the combined aqueous layer with extraction solvent; and h) concentrating the combined organic layers obtained in step g), and purifying the crude residue by flash chromatography to afford halogenated aromatic and / or heteroaromatic compound. wherein aromatic and / or heteroaromatic compounds is selected from the group consisting of (un)substituted aryl, (un)substituted heteroaryl, wherein substituted group is selected form alkyl, alkoxy, aryloxy, hydroxyl, ester, free amine, and sulfide hydroxyl.

[0052] ABBREVIATIONS USED

[0053] PVDC= Polyvinylidene Chloride

[0054] PVC= Polyvinyl chloride dPVDC= dechlorinated polyvinylidene Chloride dPVC= dechlorinated polyvinyl chloride

[0055] DEHP= Diethylhexylphthalate

[0056] PE= Polyethylene

[0057] EVA= Ethylene vinyl acetate

[0058] PO= Polyolefin

[0059] DAB= Z-l,4-diacetoxy-2-butene

[0060] DETAILED DESCRIPTION OF THE INVENTION

[0061] The term “dechlorination” used herein means partial or relatively complete removal of chlorine groups from chemical which is being processed, preferably the removal is in the range of as low as 15% to up to 90% or 99%.

[0062] The term “room temperature” used herein means natural temperature around or temperature in the range of 25 -35 °C.

[0063] The present invention discloses a simultaneous synthesis of halogenated compounds involving the halogenation of aromatic and heteroaromatic compounds and dehalogenation of polymers such as halogenated polymers selected from but not limited to PVDC, and combinations of PVC with PVDC thereof under electrochemical conditions, by utilizing excess arenes or aromatic compounds as the limiting reagent.

[0064] The aromatic and heteroaromatic compounds are selected from but not limited to (un)substituted aryl, (un)substituted heteroaryl, wherein the substituted group is selected from alkyl, alkoxy, aryloxy, hydroxyl, ester, free amine, and sulfide hydroxyl.

[0065] The halogenated aromatic / heteroaromatic compounds are selected from the group consisting of: i. l-Chloro-4-ethoxybenzene (2a); ii. l-Chloro-4-methoxybenzene (2b); iii. 4-Chloro-l,2-dimethoxybenzene (2c) and l,2-Dichloro-4,5- dimethoxybenzene (2c'); iv. 2-Chloro-l,3,5-triethylbenzene (2d); v. 2,4-Dichloro-l,3,5-trimethoxybenzene (2e') and 2-Chloro-l,3,5- trimethoxybenzene (2e); vi. Methyl 5-chloro-2-methoxybenzoate (2f); vii. l-(3-Chloro-lH-indol-l-yl)-2,2-dimethylpropan-l-one (2g); viii. 1 -(3 -Chloro- lH-indol-l-yl)ethan-l -one (2h); ix. Ethyl 3-chloro-lH-indole-2-carboxylate (2i); x. Ethyl 3,5-dichloro-lH-indole-2-carboxylate (2j); xi. 4-Chloro-l -phenyl- IH-pyrazole (2k); xii. 4-Chloro-3-phcnyl-5-(trifhioromcthyl)-l H-pyrazolc (21); xiii. 2-Chloro-5-phenylthiophene (2m); xiv. 3 -Chlorobenzo [b] thiophene (2n); xv. 2-Chloro-3-methylbenzo[b]thiophene (2o); and xvi. 4,5-Dichloro-l-phenyl-lH-imidazole (2p).

[0066] The above-mentioned chlorinated aromatic and heteroaromatic compounds are represented in Fig. 9.

[0067] A process for the chlorination of aromatic and / or heteroaromatic compounds using chlorinated polymer materials selected from a group consisting PVC, PVDC / PVC blister film, PVDC-PO multilayer food plastic, heat stabilizer integrated with PVDC or combinations thereof is conducted in continuous flow also by employing electro flow set up (Fig. 8), wherein the electro-flow set up comprises:

[0068] 1. Inlet flow,

[0069] 2. Current collectors,

[0070] 3. Electrodes,

[0071] 4. Isolation Gasket,

[0072] 5. Copper screw for applying current,

[0073] 6. Outlet flow, and

[0074] 7. End plates.

[0075] The continuous flow process for the chlorination of aromatic and / or heteroaromatic compounds using chlorinated polymer materials comprising the steps of: a) preparing a stock solution of reaction mixture consisting of aromatic and / or heteroaromatic compound, tetrabutylammonium tetrafluoroborate (nBu4NBF4), and chlorinated / dichlorinated polymer material in DMF; b) making the 20 mL volume of the electrochemical cell and applying the current by using a power-supply unit from AXIOMET AX-3OO3P; c) passing the 60 ml of the stock solution as prepared at step a) through the cell at a flow rate of 0.8 mL / min at 1.0 A current (first pass); d) passing the mixture prepared in step a) through the cell again at a flow rate of 0.8 mL / min at 2.0 A current (second pass); e) collecting the solution and adding to cold methanol (150 mL) (0 °C) and the filtering the polymer by silica frit; f) concentrating the filtrate under reduced pressure; diluting the remaining reaction mixture with ethyl acetate; g) washing the organic layer obtained in step f) with water three times and extracting the combined aqueous layer with ethyl acetate; and h) concentrating the combined organic layers obtained in step g), and purifying the crude residue by flash chromatography on silica gel (pet ether / ethyl acetate -> 20:1) to obtain chlorinated aromatic and / or heteroaromatic compound; wherein aromatic and / or heteroaromatic compounds are as defined above. The present invention discloses a simultaneous dechlorination of PVDC, when it is used as a chlorinating agent. While performing chlorination of aromatics and heteroaromatics, the PVDC is used in excess (4.0 equivalent). Therefore complete conversion may lead to 12.5% dechlorination. A different strategy is adopted in order to achieve a higher degree of dechlorination. PVDC (4.0 mmol) is reacted for the chlorination of phenetole (1.0 mmol) as an representative example. After completion of 24 h the conversion to chlorination product is determined by gas chromatography and the dechlorinated polymer is collected and dried under vacuum. The same experiment is repeated with the obtained polymer under the same reaction conditions. Likewise, after 10 cycles the residual polymer is collected, which is found insoluble in DMF. No further chlorination reaction is performed with that.

[0076] The resulting material is dried under vacuum and analyzed, which is summarized below in Table 1.

[0077] Table 1. Dechlorination of PVDC by repeated chlorine removal It can be seen from Table 1 data that to achieve nearly 100% conversion or chlorination product, at least the same or more amount of dechlorination is expected. Furthermore, the weight loss of the dechlorinated PVDC is calculated from thermogravimetric analysis and the chlorine removal is calculated. Both the results support the high degree of dechlorination for chlorine recycling from PVDC. The obtained dechlorinated PVDC is subjected to Raman measurement. Peaks in the region 500 to 3000 cm-1 indicate the presence of unsaturated (sp2 and sp) carbon nuclei generated during the dechlorination process. Experimental Raman shift suggests the formation of graphitic material that may find applications in electronics materials. (Fig. 7).

[0078] The present invention discloses that the dehalogenated polymer obtained is subjected to cross-metathesis with ethylene, leading to the production of low molecular weight vinyl / diene compounds as value added products. The value-added products cover but not limited to essential compounds / polymers as products i.e., butadiene, ethylene, propylene, hexene, octene, decene, dodecene, polyacetylene, etc. The present invention discloses a continuous flow electrochemical process for recycling of PVDC.

[0079] The present invention provides a process for the controlled synthesis of polymeric materials via an ethylene-mediated metathesis reaction conducted with said dechlorinated polymers and under controlled environment using a glass vial equipped with specialized apparatus, wherein the process comprises the steps of: a. charging the dechlorinated polymer and metathesis catalyst in a glass vial, pre-cooled under vacuum, and sealing with screw cap and transitioning into a larger Schlenk-type container; b. introducing a dry solvent into the vial in step a) under inert atmosphere and transferring the vial into autoclave and purging with ethylene gas three times with 30 bar pressure; c. pressurizing the autoclave with 25 bar ethylene gas at a temperature in the range of 75-80°C for a time period of 2-2.5 hr; and d. cooling the autoclave at a temperature in the range of 25-35°C and releasing the ethylene pressure and isolating metathesis products by adding suitable solvent.

[0080] Further, the reaction mixture undergoes filtration through a silica bed, and the filtrate is collected for analysis using multiple spectroscopic and chromatographic techniques such. In an example, the process for controlled synthesis of metathesis products from dechlorinated PVC employing a controlled reaction setup within a glass vial equipped with specialized apparatus is mentioned. Initially, the glass vial, cooled under vacuum conditions, is transferred into an inert atmosphere within a glove box. Subsequently, dechlorinated PVC and Grubbs-II catalyst (15 wt %) are introduced into the vial. This apparatus is sealed using a screw cap and transitioned into a larger Schlenk-type container outside the glove box. Following this, dry THF is added to the vial under inert conditions. The vial is then transferred into an autoclave and subjected to three purges with ethylene gas (30 bars). The autoclave is pressurized to 25 bars of ethylene pressure at 80°C for duration of 2 hours. After said reaction time, the autoclave is cooled to room temperature (25 to 35 °C), excess ethylene pressure is released, and the apparatus is opened. The crude reaction mixture undergoes preliminary analysis via NMR. Subsequently, methanol is added to the reaction mixture to precipitate the metathesis products, yielding 45 mg of solid. The solid products are subjected to analysis using GPC while the filtrate is passed through a silica bed and further analyzed.

[0081] The present invention discloses a process for chlorination of phenetole and simultaneous dechlorination of polymers, wherein polymer materials used for the chlorination are selected from a polymer group consisting of PVDC / PVC blister film, PVDC-PO multilayer food plastic, heat stabilizer integrated with PVDC or combinations thereof.

[0082] The present invention discloses a process for chlorination of phenetole and simultaneous dechlorination of polymers derived from dichlorinated monomers, wherein PVDC / PVC blister film comprising a PVDC coating, serves as a chlorinating reagent. Generally, the blister film is used in pharmaceutical packaging due to its exceptional resistance against oxygen and moisture.

[0083] The present invention further discloses a process for chlorination of phenetole under electrochemical conditions, wherein PVDC-PO multilayer food plastic comprising PE- EVA-PVDC-EVA-PE, serves as a chlorinating reagent.

[0084] The present invention discloses a process for chlorination of phenetole, wherein heat stabilizer integrated with PVDC serves as a chlorinating reagent. The present invention discloses a process for chlorination of phenetole, wherein additive such as diethylhexylphthalate (DEHP) may be used optionally with PVDC as a chlorinating agent.

[0085] The present invention discloses a process for chlorination of aromatic and / or heteroaromatic compounds using dichlorinated polymer materials in batch as well as continuous mode method.

[0086] The resulting dechlorinated PVC (dPVC) or PVDC is subjected to cross-metathesis with alkene such as ethylene, leading to the production of low molecular weight value added products such as vinyl / diene compounds.

[0087] The present invention discloses a process for the chlorination of phenetole utilizing polyvinyl chloride (PVC) as a chlorinating reagent under electrochemical conditions in an undivided cell. The method involves maintaining a constant current within the range of 10- 20 mA for about 16-24 hours of reaction time period, alternating the polarity every 15 to 30 minutes, and utilizing approximately 6-8 equivalents of PVC to achieve full conversion. The resulting chlorination product is isolated in about 70% to 90% yield, obtaining a mixture of para and ortho isomeric forms.

[0088] The present invention further discloses a process for chlorination of phenetole utilizing commercially available tubing as the chlorinating reagent on a 1 mmol scale. The robustness of the process is established through experimental validation, wherein the reaction achieved completion within approximately 20-24 hours, yielding the desired product in an exemplary 85% to 95% yield. This demonstrates the efficacy and efficiency of utilizing commercially available tubing as a reagent for the chlorination of phenetole, showcasing its practical applicability and scalability in delivering high yields of the desired chlorination product within a reasonable timeframe.

[0089] The present invention discloses a process for chlorinating phenetole utilizing commercially available PVDC as the chlorinating reagent. Through meticulous experimentation and optimization, the process achieves efficient chlorination in full conversion. The process involves employing about 2-4 equivalents of PVDC within an undivided cell configuration, maintaining about 16-24 hours reaction duration at a constant current of approximately 10- 20 mA, and alternating polarity every 15-30 minutes. The resulting chlorination product is obtained in a 65% - 85% yield, comprising a blend of ortho and para compounds. The process works with 4 equiv. of PVDC giving the chlorination product with full conversion wherein for PVC 8 equivalent is needed. However, in previously conducted experiments, 4 equivalents of PVDC did not give satisfactory results. Modification of process parameters that are included in the present invention are essential. The polymer needs to be dissolved in a dimethyl formamide solvent by heating at 70 °C before the electrolysis at room temperature. The utilization of PVDC as a chlorinating reagent exhibits exceptional efficiency, enabling high conversion rates within a specified reaction timeframe. Moreover, the capability of the disclosed process to produce the desired chlorination product in significant yield demonstrates its practical viability for industrial-scale applications. Additionally, the calculated dechlorination rate of 82.5% signifies the stability and effectiveness of the process, establishing its potential for commercial utilization in chlorination chemistry.

[0090] EXAMPLES

[0091] Following examples are given by way of illustration therefore should not be construed to limit the scope of the invention.

[0092] Example 1: Chlorination of phenetole using PVC

[0093] The chlorination of phenetole using commercially available PVC as a chlorinating reagent was commenced under electrochemical conditions using an undivided cell. Following the screening of various reaction conditions, the desired chlorination proceeded with full conversion utilizing 8 equivalent PVC over a 24-hour reaction period, maintaining a constant current of 10 mA and altering polarity every 15 minutes. The resultant chlorination product, comprising a mixture of para and ortho products, was isolated with a yield of 70%. The estimated dechlorination of the polymer stood at 12.5%, determined based on the conversion of the chlorination reaction.

[0094] Example 2: Chlorination of phenetole using commercially available PVC-tubing

[0095] The robustness of the method was evaluated by employing commercially available tubing as a chlorinating reagent for the chlorination of phenetole on a 1 mmol scale. Completion of the reaction within 20 hours yielded the product at an 87% yield. Example 3: Chlorination of phenetole using PVDC

[0096] Subsequently, commercially available PVDC was utilized as a chlorinating reagent for phenetole chlorination. Following optimization, full conversion in the desired chlorination was achieved using 4 equivalents of PVDC within an undivided cell, maintaining a constant current of 10 mA for 24 hours, with polarity changes occurring every 15 minutes. The resultant chlorination product, a blend of ortho / para compounds, was isolated, yielding 68%. The resulting dechlorination was calculated at 12.5% based on the conversion of the chlorination reaction.

[0097] Example 4: Chlorination of aromatics using PVDC as chlorinating reagent

[0098] The investigation focuses on exploring the chlorination reactions of diverse aromatic and heteroaromatic compounds using the refined conditions. Encouragingly, significant conversions were achieved for 1,3,5-triethylbenzene, 1,3,5-trimethoxybenzene, and benzo[d][l,3]dioxoleas confirmed by gas chromatography analysis revealing complete conversion in all cases. The lower isolated yields, in comparison to the conversion rates, are possibly linked to losses occurring during subsequent workup and purification stages.

[0099] Attention was subsequently directed towards enhancing the dechlorination percentage. In pursuit of this goal, PVDC was utilized as a limiting reagent, with an excess of the aromatic compound. Several conditions were evaluated, and considering the chlorination reaction, the anticipated dechlorination exceeds 50%, an already notably high value, while the goal is to achieve 100%.

[0100] Example 5: General procedure (A) for electrochemical chlorination of aromatic and heteroaromatic compounds

[0101] A standard 10-mL ElectraSyn vial was charged with a magnetic stir bar, PVDC (155.1 mg, 1.60 mmol), and DMF (8 mL). The mixture was stirred at 70 °C for 20 minutes to make a clear solution. Then, the reaction mixture was transferred to room temperature. Tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) and substrate (0.40 mmol, 1.0 equiv) were added, respectively. IKA Graphite (anode) and Graphite (cathode) plate electrodes were connected to an ElectraSyn vial cap. Then, it was placed into the ElectraSyn setup, and the following steps were followed: New experiment -> Constant current -> 10 mA -> Time -> xx h -> No reference electrode -> Alternate polarity -> 15 minutes -> Substrate -> 0.4 mmol-> start. After completion, the reaction mixture was added to cold methanol (50 mL) (0 °C) for precipitation, and the polymer was filtered by silica frit. The remaining filtrate was concentrated under reduced pressure to remove methanol. The concentrated reaction mixture was diluted with diethyl ether, and the organic layer was washed with water (three times). The combined aqueous layer was extracted with diethyl ether (two times). The combined organic layers were dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude residue was purified by flash column chromatography on silica gel.

[0102] Example 6: General procedure (B) for electrochemical chlorination of aromatic and heteroaromatic compounds

[0103] A standard 10-mL ElectraSyn vial was charged with a magnetic stir bar, PVDC (155.1 mg, 1.60 mmol), and DMF (8 mL). The mixture was stirred at 70 °C for 20 minutes to make a clear solution. Then, the reaction mixture was transferred to room temperature. Tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) and substrate (0.40 mmol, 1.0 equiv) were added, respectively. IKA Graphite (anode) and Graphite (cathode) plate electrodes were connected to an ElectraSyn vial cap. Then, it was placed into the ElectraSyn setup, and the following steps were followed: New experiment -> Constant current -> 10 mA -> Time -> xx h -> No reference electrode -> Alternate polarity -> 15 minutes -> Substrate -> 0.4 mmol-> start. After completion of the reaction, the reaction mixture was added to cold methanol (50 mL) (0 °C) for precipitation, and the polymer was filtered by silica frit. The remaining filtrate was concentrated under reduced pressure to remove methanol. The concentrated reaction mixture was diluted with ethyl acetate, and the organic layer was washed with water three times. The combined aqueous layer was extracted with ethyl acetate (two times). The combined organic layers were dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude residue was purified by flash column chromatography on silica gel.

[0104] Example 5: Characterization of synthesized compounds i. l-Chloro-4-ethoxybenzene (2a) General procedure A was followed using ethoxybenzene (la) (48.9 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 20 h. Purification by column chromatography using (pet ether / diethyl ether = 100:2) yielded l-chloro-4-ethoxybenzene (2a) (45.1 mg, 72%) as a colourless oil (p / o ratio = 19:1).

[0105] ’ H NMR (400 MHz, CDCh) 6 = 7.20 (d, J = 9.0 Hz, 2H), 6.79 (d, J = 9.0 Hz, 2H), 3.96 (q, J = 7.0 Hz, 2H), 1.38 (t, J = 7.0 Hz, 3H).13C NMR (101 MHz, CDCh) 6 = 157.7 (Cq), 129.4 (CH), 125.4 (Cq), 115.8 (CH), 63.8 (CH2), 14.8 (CH3). ii. l-Chloro-4-methoxybenzene (2b)

[0106] General procedure A was followed using anisole (lb) (43.3 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 20 h. Purification by column chromatography using (pet ether / diethyl ether = 100:2) yielded l-chloro-4-methoxybenzene (2b) (24.0 mg, 42%) as a colourless oil (p / o ratio = 19:1).

[0107] ’ H NMR (400 MHz, CDCh) 6 = 7.24 (d, J = 9.0 Hz, 2H), 6.83 (d, J = 9.0 Hz, 2H), 3.79 (s, 3H).13C NMR (101 MHz, CDCh) 6 = 158.3 (Cq), 129.4 (CH), 125.7 (Cq), 115.3 (CH), 55.6 (CH3). iii. 4-Chloro-l,2-dimethoxybenzene (2c) and l,2-Dichloro-4,5- dimethoxybenzene (2c')

[0108] General procedure A was followed using 1,2-dimethoxybenzene (1c) (55.3 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 30 h. Purification by column chromatography using (pet ether / diethyl ether = 100:2) yielded 4-chloro- 1,2- dimethoxybenzene (2c) .7 mg, 40%) and l,2-dichloro-4,5-dimethoxybenzene (2c') (9.2 mg, 11%) as a mixture in 3.7:1 ratio.

[0109] 1H NMR (400 MHz, CDCh) 6 = 6.90 (s, 0.56H, minor), 6.87 (dd, J = 8.5, 2.3 Hz, 1H), 6.84 (d, J = 2.3 Hz, 1H), 6.77 (d, J = 8.5 Hz, 1H), 3.86 (s, 3H), 3.85 (s, 3H), 3.85 (s, 1.68H, minor).13C NMR (101 MHz, CDCh) 6 = 149.7 (Cq), 148.4 (Cq, minor), 147.9 (Cq), 125.7 (Cq), 123.6 (Cq, minor), 120.4 (CH), 113.0 (CH, minor), 112.2 (CH), 112.0 (CH), 56.4 (CH3, minor), 56.2 (CH3), 56.1 (CH3). iv. 2-Chloro-l,3,5-triethylbenzene (2d)

[0110] General procedure A was followed using 1,3,5-triethylbenzene (Id) (64.9 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 24h. Purification by column chromatography using (pet ether / diethyl ether = 100:2) yielded 2-chloro-l,3,5-triethylbenzene (2d) (59.8 mg, 76%) as a colourless liquid.

[0111] 1H NMR (400 MHz, CDC13) 8 = 6.94 (s, 2H), 2.77 (q, J = 7.5 Hz, 4H), 2.61 (q, J = 7.6 Hz, 2H), 1.31 - 1.25 (m, 9H).13C NMR (101 MHz, CDC13) 8 = 142.6 (Cq), 141.8 (Cq), 130.8 (Cq), 126.7 (CH), 28.5 (CH2), 27.5 (CH2), 15.7 (CH3), 14.3 (CH3). v. 2,4-Dichloro-l,3,5-trimethoxybenzene <2e') and 2-Chloro-l,3,5- trimethoxybenzene (2e)

[0112] General procedure B was followed using 1,3,5-trimethoxybenzene (le) (67.3 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 8 h. Purification by column chromatography using (pet ether / ethyl acetate = 10:1) yielded 2, 4-dichloro- 1,3,5- trimethoxybenzene (2e') (42.7 mg, 45%) as a white solid and 2-chloro-l,3,5- trimethoxybenzene (2e) (12.2 mg, 15%) as a white solid in 3:1 ratio.

[0113] ’ H NMR (400 MHz, CDC13) 8 = 6.35 (s, 1H), 6.16 (s, 0.66H, minor), 3.89 (s, 6H), 3.87 (s, 3H), 3.86 (s, 1.98H, minor), 3.79 (s, 0.99H, minor).

[0114] 13C NMR (101 MHz, CDC13) 8 = 159.5 (Cq, minor), 156.6 (Cq, minor), 154.9 (Cq), 153.9 (Cq), 109.8 (Cq), 102.7 (Cq, minor), 93.3 (CH), 91.7 (CH, minor), 60.7 (CH3), 56.6 (CH3), 56.4 (CH3, minor), 55.6 (CH3, minor). vi. 2,4-Dichloro-l,3,5-trimethoxybenzene ( 2e' )

[0115] General procedure B was followed using 1,3,5-trimethoxybenzene (le) (67.3 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 24 h. Purification by column chromatography using (pet ether / ethyl acetate = 10:1) yielded 2,4-dichloro-l,3,5- trimethoxybenzene (2e') (36.0 mg, 38%) as a white solid as a sole product.

[0116] ’ H NMR (400 MHz, CDC13) 6 = 6.37 (s, 1H), 3.90 (s, 6H), 3.88 (s, 3H).13C NMR (101 MHz, CDCI3) 6 = 155.0 (Cq), 154.0 (Cq), 109.9 (Cq), 93.4 (CH), 60.7 (CH3), 56.7 (CH3). vii. Methyl 5-chloro-2-methoxybenzoate (2f)

[0117] General procedure B was followed using methyl 2-methoxybenzoate (If) (66.5 mg, 0.40 mmol), PVDC (155.2 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 48 h. Purification by column chromatography using (pet ether / ethyl acetate) = 10:1) yielded methyl 5-chloro-2- methoxybenzoate (2f) (49.0 mg, 61%) as a colourless oil.

[0118] ’ H NMR (400 MHz, CDCI3) 6 = 7.76 (d, J = 2.7 Hz, 1H), 7.41 (dd, J = 8.9, 2.7 Hz, 1H), 6.91 (d, J = 8.9 Hz, 1H), 3.89 (s, 3H), 3.88 (s, 3H).13C NMR (101 MHz, CDCI3) 6 = 165.5 (Cq), 157.9 (Cq), 133.3 (CH), 131.5 (CH), 125.3 (Cq), 121.4 (Cq), 113.6 (CH), 56.5 (CH3), 52.4 (CH3). viii. l-(3-Chloro-lH-indol-l-yl)-2,2-dimethylpropan-l-one (2g)

[0119] General procedure B was followed using l-(lH-indol-l-yl)-2,2-dimethylpropan-l-one (lg).(80.5 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate ("BU4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 5 mA for 16 h. Purification by column chromatography using (pet ether / ethyl acetate = 20:1) yielded l-(3- chloro-lH-indol-l-yl)-2,2-dimethylpropan-l-one (2g) (68.8 mg, 73%) as a white solid.

[0120] ’ H NMR (400 MHz, CDCI3) 6 = 8.52 (d, J = 8.3 Hz, 1H), 7.74 (s, 1H), 7.59 (dd, J = 7.7, 0.6 Hz, 1H), 7.45 - 7.39 (m, 1H), 7.35 (dd, J = 7.6, 7.7 Hz, 1H), 1.52 (s, 9H).13C NMR (101 MHz, CDCI3) 6 = 176.6 (Cq), 136.0 (Cq), 127.2 (Cq), 126.5 (CH), 124.2 (CH), 122.1 (CH), 118.2 (CH), 117.6 (CH), 113.2 (Cq), 41.4 (Cq), 28.8 (CH3). ix. l-(3-Chloro-lH-indol-l-yl)ethan-l-one (2h) General procedure B was followed using l-(lH-indole-l-yl)ethan-l-one (Ih) (63.7 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 24 h. Purification by column chromatography using (pet ether / ethyl acetate = 4:1) yielded 1 -(3 -chloro- IH-indol- l-yl)ethan-l-one (2h) (20.1 mg, 26%) as a white solid.

[0121] 1H NMR (400 MHz, CDC13) 6 = 8.43 (d, J = 8.0 Hz, IH), 7.64 - 7.56 (m, IH), 7.47 - 7.39 (m, 2H), 7.36 (dd, J = 7.6, 7.7 Hz, IH), 2.62 (s, 3H).13C NMR (101 MHz, CDCI3) 6 = 168.0 (Cq), 134.8 (Cq), 128.2 (Cq), 126.5 (CH), 124.3 (CH), 121.6 (CH), 118.6 (CH), 116.8 (CH), 114.1 (Cq), 24.0 (CH3). x. Ethyl 3-chloro-lH-indole-2-carboxylate (2i)

[0122] General procedure B was followed using ethyl lH-indole-2-carboxylate (li) (75.7 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 5 mA for 16 h. Purification by column chromatography using (pet ether / ethyl acetate = 4:1) yielded ethyl 3 -chloro- lH-indole-2- carboxylate (2i) (52.8 mg, 59%) as a white solid.

[0123] 1H NMR (400 MHz, CDCI3) 6 = 9.32 (s, IH), 7.72 (d, J = 8.1 Hz, IH), 7.41 - 7.35 (m, 2H), 7.22 (dd, J = 8.1, 7.2 Hz, IH), 4.49 (q, J = 7.1 Hz, 2H), 1.47 (t, J = 7.1 Hz, 3H).13C NMR (101 MHz, CDCI3) 6 = 161.4 (Cq), 135.0 (Cq), 126.6 (CH), 126.3 (Cq), 122.5 (Cq), 121.4 (CH), 120.3 (CH), 112.5 (Cq), 112.2 (CH), 61.6 (CH2), 14.5 (CH3). xi. Ethyl 3,5-dichloro-lH-indole-2-carboxylate (2j)

[0124] General procedure B was followed using ethyl-5-chloro-lH-indole-2-carboxylate (Ij) (89.5 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 5 mA for 16 h. Purification by column chromatography using (pet ether / ethyl acetate = 4:1) yielded ethyl 3,5-dichloro-lH-indole-2-carboxylate (2j) (63.0 mg, 61%) as a white solid.

[0125] ’ H NMR (400 MHz, CDCI3) 6 = 9.08 (s, IH), 7.69 (s, IH), 7.32 (s, 2H), 4.47 (q, J = 7.1 Hz, 2H), 1.46 (t, J = 7.1 Hz, 3H).13C NMR (101 MHz, CDCI3) 6 = 160.9 (Cq), 133.1 (Cq), 127.4 (Cq), 127.3 (CH), 127.3 (Cq), 123.8 (Cq), 119.7 (CH), 113.5 (CH), 111.8 (Cq), 61.8 (CH2), 14.5 (CH3). xii. 4-Chloro-l-phenyl-lH-pyrazole (2k)

[0126] General procedure B was followed using 1 -Phenyl- IH-pyrazole (Ik) (57.7 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 24 h. Purification by column chromatography using (pet ether / ethyl acetate = 20:1) yielded 4-chloro-l-phenyl-lH-pyrazole (2k) (55.0 mg, 77%) as a white solid.

[0127] ’ H NMR (400 MHz, CDC13) 6 = 7.89 (s, 1H), 7.64 (s, 1H), 7.63 (d, J = 7.8 Hz, 2H), 7.44 (dd, J = 7.8, 7.4 Hz, 2H), 7.30 (t, J = 7.4 Hz, 1H).13C NMR (101 MHz, CDCI3) 6 = 139.8 (Cq), 139.5 (CH), 129.6 (CH), 127.0 (CH), 124.9 (CH), 119.0 (CH), 112.5 (Cq). xiii. 4-Chloro-3-phenyl-5-(trifhioromethyl)-lH-pyrazole (21)

[0128] General procedure B was followed using 3-Phenyl-5-(trifluoromethyl)-lH-pyrazole (11) (84.9 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 48 h. Purification by column chromatography using (pet ether / ethyl acetate = 10:1) yielded 4- chloro-3-phenyl-5-(trifluoromethyl)-lH-pyrazole (21) (79.9 mg, 81%) as a white solid.

[0129] 1H NMR (400 MHz, DMSO) 8 = 14.39 (s, 1H), 7.75 (d, J = 7.1 Hz, 2H), 7.55 (dd, J = 7.3, 7.1 Hz, 2H), 7.49 (t, J = 7.3 Hz, 1H).13C NMR (101 MHz, DMSO) 8 = 140.6 (Cq), [138.9, 138.5, 138.2, 137.8] (Cq, q, J = 36.0 Hz), 129.7 (CH), 129.1 (CH), 127.3 (CH), 126.4 (Cq), [125.0, 122.3, 119.7, 117.0] (Cq, q, J = 268.0 Hz), 104.2 (Cq).19F NMR (376 MHz, DMSO) 8 = -61.27. xiv. 2-Chloro-5-phenylthiophene (2m)

[0130] General procedure A was followed using 2-Phenylthiophene (Im) (64.1 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 5 mA for 20 h. Purification by column chromatography using (pet ether / diethyl ether = 100:2) yielded 2-chloro-5-phenylthiophene (2m) (35.1 mg, 45%) as a white solid in >10:1 ratio of 2m and 2m'. ’ H NMR (400 MHz, CDCI3) 6 = 7.52 (d, J = 7.1 Hz, 2H), 7.38 (dd, J = 7.3, 7.1 Hz, 2H), 7.30 (t, J = 7.3 Hz, 1H), 7.07 (d, J = 3.9 Hz, 1H), 6.90 (d, J = 3.9 Hz, 1H).13C NMR (101 MHz, CDCI3) 6 = 143.1 (Cq), 133.8 (Cq), 129.3 (Cq), 129.1 (CH), 128.0 (CH), 127.2 (CH), 125.7 (CH), 122.4 (CH). xv. 3-Chlorobenzo[b]thiophene (2n)

[0131] General procedure A was followed using benzo [b] thiophene (In) (53.7 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 5 mA for 24 h. Purification by column chromatography using (pet ether / diethyl ether = 100:2) yielded 3 -chlorobenzo [b] thiophene (2n) (32.8 mg, 48%) as a colourless oil in >10:1:1 ratio of 2n, 2n' and 2n".

[0132] ’ H NMR (400 MHz, CDCI3) 6 = 7.88 (d, J = 8.4 Hz, 1H), 7.85 (d, J = 8.0 Hz, 1H), 7.48 (dd, J = 8.0, 7.4 Hz, 1H), 7.43 (dd, J = 8.4, 7.6 Hz, 1H), 7.32 (s, 1H).13C NMR (101 MHz, CDCI3) 6 = 138.5 (Cq), 136.2 (Cq), 125.4 (CH), 125.0 (CH), 123.0 (CH), 121.9 (CH), 121.3 (Cq), 120.9 (CH). xvi. 2-Chloro-3-methylbenzo[b]thiophene (2o)

[0133] General procedure B was followed using 3 -methylbenzo [b] thiophene (lo) (59.3 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 24 h. Purification by column chromatography using (pet ether / diethyl ether = 100:1) yielded 2-chloro-3- methylbenzo[b] thiophene (2o) (41.0 mg, 56%) as a colourless oil.

[0134] ’ H NMR (400 MHz, CDCI3) 6 = 7.70 (d, J = 7.7 Hz, 1H), 7.61 (d, J = 7.3 Hz, 1H), 7.39 (dd, J = 7.4, 7.3 Hz, 1H), 7.34 (dd, J = 7.7, 7.3 Hz, 1H), 2.38 (s, 3H).13C NMR (101 MHz, CDCI3) 6 = 138.9 (Cq), 137.5 (Cq), 129.0 (Cq), 126.7 (Cq), 124.7 (CH), 124.6 (CH), 121.9 (CH), 121.7 (CH), 11.6 (CH3). xvii. 4,5-Dichloro-l-phenyl-lH-imidazole (2p)

[0135] General procedure B was followed using 1 -Phenyl- IH-imidazole (Ip) (57.7 mg, 0.40 mmol), PVDC (155.1 mg, 1.60 mmol), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (395.1 mg, 1.2 mmol) in DMF (8 mL) at 10 mA for 24 h. Purification by column chromatography using (pet ether / ethyl acetate = 2:1) yielded 4,5-dichloro-l-phenyl-lH- imidazole (2p) (30.7 mg, 36%) as a white solid.

[0136] ’ H NMR (400 MHz, CDC13) 6 = 7.54 -7.51 (m, 4H), 7.36 - 7.34 (m, 2H).13C NMR (101 MHz, CDCI3) 6 = 134.7 (Cq), 134.7 (CH), 129.8 (CH), 129.6 (CH), 127.5 (Cq), 125.7 (CH), 114.1 (Cq).

[0137] The potentials of the method were tested using different mixed polymers or in the presence of additives, and the results are listed below:

[0138] Example 7: Chlorination of phenetole using PVDC / PVC blister film

[0139] For packaging medicine, PVDC / PVC blister film is employed due to its high resistance to oxygen and moisture. A PVDC / PVC pharmaceutical blister film comprises a PVDC coating on PVC. Utilizing this film, the chlorination of phenetole was conducted, resulting in successful conversion in the desired chlorination reaction.

[0140] PVDC / PVC pharma blister film was also used for chlorination of 1 -phenyl- IH-pyrazole (Ik). When 400 mg of the blister film that contains 44 mg of PVDC with tetrabutylammonium tetrafluoroborate was used, the product 4-chloro-l -phenyl- 1H- pyrazole (2k) was obtained in 58% yield after 24 h reaction time. Next, a waste pharma blister pack (400 mg) was used, and the desired chlorination product 4 -chloro- 1-phenyl- IH-pyrazole (2k) was obtained in 56% yield

[0141] Example 8: Chlorination of phenetole using PVDC-PO multilayer food plastic

[0142] The PVDC-PO multilayer food plastic, serving as a single-use food packaging material, comprises PE-EVA-PVDC-EVA-PE layers (Food multilayer), comprising PVDC, PE and EVA. Employing this material for the chlorination of phenetole under electrochemical conditions, the reaction was conducted both in the presence and absence of polyolefins, resulting in consistent outcomes. The chlorination reaction proceeded to full conversion within 20 hours, yielding the chlorinated product at a 70% isolated yield.

[0143] When 1.0 g food multilayer packaging that contains 150 mg of PVDC was used for the chlorination of 1 -phenyl- IH-pyrazole (Ik) the desired chlorination product 4-chloro-l- phenyl-lH-pyrazole (2k) was obtained with 82% yield after 24 h. Example 9: Chlorination of phenetole using PVDC with heat stabilizer

[0144] The chlorination of phenetole was conducted using a PVDC -containing heat stabilizer sample under our developed chlorination conditions. Notably, the presence of the heat stabilizer had no impact on the efficiency of the chlorination method. A favourable conversion for the chlorination product was achieved within a 16-hour reaction time.

[0145] When a compression molded sheet of PVDC (with heat stabilizer) (200 mg) was used directly for the chlorination of 1 -phenyl- IH-pyrazole (Ik) without any exception, the desired chlorination product 4-chloro-l-phenyl-lH-pyrazole (2k) was obtained with 85% yield in 19 h.

[0146] Example 10: Chlorination of phenylpyrazole in continuous flow method

[0147] An electroflow setup was made (Fig. 8) for the electrochemical chlorination of 1-phenyl- IH-pyrazole (Ik) using PVDC. The flow cell consists of end plate, current collector, electrode, gasket electrode, current collector, end plate. A stock solution of the reaction mixture was prepared using 1 -phenyl- IH-pyrazole (Ik) (0.1 M), tetrabutylammonium tetrafluoroborate (nBu4NBF4) (0.1 M), and polyvinylidene chloride (PVDC, Sigma Aldrich-Goodfellow) (0.2 M) in DMF. The volume of the electrochemical cell was 20 mL. A peristaltic pump was used to maintain the flow rate of 0.8 mL / min. The current was applied by a power-supply unit from AXIOMET AX-3OO3P. Then 60 ml of the stock solution was passed through the cell at a flow rate of 0.8 mL / min at 1.0 A current (first pass). After a single pass, the solution contained both the mixture of reactant and product determined by TLC. To further improve the conversion the mixture was passed through the cell again at a flow rate of 0.8 mL / min at 2.0 A current (second pass). The solution was collected and the reaction mixture was added to cold methanol (150 mL) (0 °C) and the polymer was filtered by silica frit. The filtrate was concentrated by reduced pressure. The remaining reaction mixture was diluted with ethyl acetate, and the organic layer was washed with water three times. The combined aqueous layer was extracted with ethyl acetate. The combined organic layers were dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The crude residue was purified by flash chromatography on silica gel (pet ether / ethyl acetate -> 20:1) to afford 4-chloro-l-phenyl- IH-pyrazole (2k) (696.6 mg, 65%) as a white solid. Example 11: Electrochemical deconstruction of PVC and PVDC

[0148] Dechlorinated polymers may find applications in battery materials. Furthermore, various value-added products can be accessed by cross-metathesis reactions, providing alternatives to petrochemicals. It is illustrated that dPVC can be subjected to cross-metathesis to yield short-chain vinyl or diene monomers. These vinyl or diene compounds can serve as intermediates for either polymerization or preparation of organic compounds.

[0149] Example 12: General procedure: Metathesis of dechlorinated PVC (dPVC) with ethylene

[0150] A glass vial (4 mL) equipped with Teflon coated magnetic needle was cooled under a vacuum and transferred to a glove box. The vial was then charged with 50 mg of dechlorinated PVC (dPVC), and suitable amount of metathesis catalyst (1-15 wt %). The reaction vial was then closed using a screw cap, transferred to a large opening Schlenk-type container, and was then taken out from the glove box. 2 mL dry solvent was added to the vial in an inert atmosphere. After that the reaction vial was shifted to an autoclave and the autoclave was purged three times using ethylene gas (30 bars). Finally, the autoclave was pressurized to the desired ethylene pressure (10-30 bar) and temperature (RT-150 °C) for the allotted time period. After the desired time period, the autoclave was cooled to room temperature (25 °C), excess ethylene pressure was released and the autoclave was opened. The vials were taken out from the autoclave. The thus obtained reaction mixture was passed through a silica bed, and the filtrate was collected and analyzed by NMR, GC, GC-MS, and GPC.

[0151] Under a vacuum, a 4 mL glass vial equipped with a Teflon-coated magnetic needle was cooled and transferred to a glove box. Subsequently, 50 mg of dechlorinated PVC and 7.5 mg (15 wt %) of Grubbs-II catalyst were added to the vial. The vial was sealed with a screw cap and then placed into a large opening Schlenk-type container outside the glove box. In an inert atmosphere, 2 mL of dry THF was introduced into the vial. The vial was then moved to an autoclave and subjected to three purges with ethylene gas (30 bars). The autoclave was pressurized to 25 bars with ethylene at 80°C for 2 hours. After the allotted time, the autoclave was cooled to room temperature (25°C), and excess ethylene pressure was released before opening the autoclave. The crude reaction mixture was analyzed using 1H NMR, and further analysis was performed by precipitating the metathesis products with methanol (yielding 45 mg of solid). The solid products obtained were subjected to GPC analysis. The filtrate was passed through a silica bed and then analyzed by GC, GCMS, and GPC for comprehensive assessment. Example 13: Comparative Example

[0152] Skelly, P. W. et al. (ChemPlusChem 88, e202300184 (2023)) reports metathesis of functionalized PVC with Z-l,4-diacetoxy-2-butene (DAB) (See below scheme) in DCM (Dichloromethane) at 40 °C under reflux. These conditions cannot be followed in the present reactions with gaseous ethylene. Hence, present reactions are under 10-30 bar ethylene pressure and not reflux.

[0153] Chlorination reaction was performed using phenetole (1 mmol) and PVDC (4 mmol) using 20 mA current for 24 h. The polymer was reused in the subsequent reaction, and the reaction was repeated 10 times. Then the recovered polymer was subjected to TGA measurement (Fig. 6A & 6B) and analysed by Raman spectra (fig. 7), and the degree of dechlorination was estimated from the weight loss to be >82%.

[0154] Theoretical calculation:

[0155] HC1 content = 75.22%; Degree of dechlorination= 0%. Experimental calculation

[0156] PVDC

[0157] 6.6 evolved dPVDC (Dechlorination of PVDC- 2)

[0158] 6.12 0.7681 mg HCl evolved

[0159] Characterization of metathesis products

[0160] 'H NMR Spectroscopy: In the proton NMR, few characteristic peaks were observed which matches with the reported values. We have assigned these peaks to the possible structures of metathesis products (Fig. 1) (6.57, 6.15, 2.76 1.16 and 0.99 ppm), which is in line with literature reports.

[0161] GC-MS analysis: The soluble part (after precipitation from methanol) of the metathesis reaction was taken. This was filtered, the filtrate was passed through the silica bed and was injected in a GC-MS. The GC and the GC-MS data was correlated and based on the observed mass in GC-MS, we have proposed few structures as shown in Fig. 2.

[0162] GPC analysis

[0163] In our attempt to confirm the depolymerization of dPVC, polymer before and after metathesis was subjected GPC analysis. The results are displayed in Fig. 4. As visible, the dPVC before metathesis displayed single peak, corresponding to a Mn of 55000 g / mol. While, dPVC after metathesis disclosed two peaks, one for the starting dPVC (Mn = 43000 g / mol) and the other one for the depolymerized low molecular fraction (Mn = 700 g / mol). These observations suggest that dPVC further breaks down to low molecular weight fractions. Both the GPC analyses data indicates slight decrease in the molecular weight, which points that the metathesis happened and long chain got break down into smaller molecules. ADVANTAGES OF THE INVENTION

[0164] • The present invention provides an improved, efficient, cost-effective, and environmentally friendly dechlorination process done in a controlled manner without generating corrosive hydrogen halide and has the potential for 100% dechlorination.

[0165] • The synthesized vinyl / diene compounds (with molecular weights ranging from 149 to 274 Da) find application in battery materials as conducting polymers.

[0166] • The integrated polymer upcy cling techniques combined with the production of halogenated compounds contribute to sustainable manufacturing processes by efficiently repurposing polymer waste materials into functional compounds.

[0167] • The present invention’s method operates using an operationally simple undivided cell under additive-free conditions. It demonstrates efficacy even in the presence of mixed plastics or stabilizers commonly found in plastics.

Claims

AMENDED CLAIMS received by the International Bureau on 30 June 2025 (30.06.2025)WE CLAIM1. A simultaneous process for halogenation of an aromatic and / or a heteroaromatic compound and dehalogenation of a polymer material via an alkene-mediated crossmetathesis reaction derived from dihalogenated monomer and subsequent preparation of a value-added product by deconstructing and / or depolymerizing the dehalogenated polymer, wherein the process comprising the steps of:

1. reacting the aromatic and / or heteroaromatic compound with the polymer material derived from dihalogenated monomer as a halide source under an additive-free electrochemical conditions in an undivided cell to obtain the halogenated aromatic and / or heteroaromatic compound and dehalogenated polymer; ii . charging the dehalogenated polymer obtained in step (i) and a metathesis catalyst in a reaction vessel followed by pre-cooling under vacuum;111. introducing a solvent into the reaction vessel of step (ii) under inert atmosphere and transferring the vessel into an autoclave and purging with ethylene gas three times with 20 to 40 bar pressure; iv. pressurizing the autoclave with 20 to 30 bar ethylene gas at a temperature in the range of 75-80°C for a time period of 2-2.5 hr; andV. cooling the autoclave at a temperature in the range of 25-35°C and releasing the ethylene pressure followed by adding a solvent to obtain the value-added product.

2. The process as claimed in claim 1, wherein said process is conducted in batch and / or in continuous flow mode.

3. The process as claimed in claim 1, wherein said aromatic and / or heteroaromatic compound is selected from the group consisting of (un)substituted aryl, (un) substituted heteroaryl, wherein substituted group is selected from the group consisting of alkyl, alkoxy, aryl oxy, hydroxyl, ester, free amine and sulfide hydroxyl.

4. The process as claimed in claim 1, wherein said polymer material is selected from the group consisting of a polyvinylidene chloride (PVDC) blister film, polyvinyl chloride (PVC) / PVDC blister film, PVDC- polyolefin (PO) multilayer food plastic, heat stabilizer integrated with PVDC or combinations thereof.

5. The process as claimed in claim 1, wherein said halogenated aromatic and / or heteroaromatic compound is selected from the group consisting of: i. l-Chloro-4-ethoxybenzene (2a); ii. 1 -Chi oro-4-m ethoxybenzene (2b); iii. 4-Chloro-l,2-dimethoxybenzene (2c) and l,2-Dichloro-4,5-dimethoxybenzene (2c ); iv. 2-Chloro-l,3,5-triethylbenzene (2d); v. 2,4-Dichloro-l,3,5-trimethoxybenzene (2e ) and 2-Chloro-l,3,5- trimethoxybenzene (2e); vi. Methyl 5-chloro-2-methoxybenzoate (2f); vii. l-(3-Chloro-lH-indol-l-yl)-2,2-dimethylpropan-l-one (2g); viii. l-(3-Chloro-lH-indol-l-yl)ethan-l-one (2h); ix. Ethyl 3-chloro-lH-indole-2-carboxylate (2i); x. Ethyl 3,5-dichloro-lH-indole-2-carboxylate (2j); xi. 4-Chloro-l-phenyl-lH-pyrazole (2k); xii. 4-Chloro-3-phenyl-5-(trifluoromethyl)-lH-pyrazole (21); xiii. 2-Chloro-5-phenylthiophene (2m); xiv. 3-Chlorobenzo[b]thiophene (2n); xv. 2-Chl oro-3 -methylbenzo[b]thiophene (2o); and xvi. 4,5-Dichloro-l-phenyl-lH-imidazole (2p).

6. The process as claimed in claim 1, wherein the additive-free electrochemical conditions comprises the polymer derived from dihalogenated monomer in a range of 2- 8 equivalents, a constant current in the range of 10-20 mA, alternating polarity at every 15-30 minutes and a time period in the range of 16-24 hours.

7. The process as claimed in claim 1, wherein yield of the halogenated aromatic and / or heteroaromatic compounds is in the range of 70-90%.

8. The process as claimed in claim 1, wherein said metathesis catalyst is Grubbs II catalyst.

9. The process as claimed in claim 1, wherein said solvent is dry THE.

10. The process as claimed in claim 1, wherein the value-added product is selected from the group consisting of butadiene, ethylene, propylene, hexene, octene, decene, dodecene, and polyacetylene or combinations thereof.

11. The process as claimed in claim 1, wherein the dehalogenated polymer is selected from the group consisting of dechlorinated PVC, and PVDC polymer or combinations thereof.

12. A continuous flow process for the halogenation of an aromatic and / or a heteroaromatic compound using halogenated polymer materials selected from a group consisting of PVC, PVDC / PVC blister film, PVDC-PO multilayer food plastic, heat stabilizer integrated with PVDC or combinations thereof, wherein the process comprises: a) preparing a stock solution of reaction mixture consisting of aromatic and / or heteroaromatic compound, tetrabutylammonium tetrafluoroborate (nBu4NBF4), halogenated polymer material in a polar solvent; b) providing an electrochemical cell and applying current to the electrochemical cell by using a power-supply unit; c) passing the stock solution as prepared at step a) through the electrochemical cell at a flow rate of 0.6-1.0 mL / min at 1.0 A current; d) passing the solution of step a) or c) through the electrochemical cell at a flow rate of 0.6- 1.0 mL / min at 2.0 A current; e) collecting the solution from step d) followed by adding in a solvent at temperature in the range of 0-2°C and filtering to obtain a filtrate; f) concentrating the filtrate of step e) under reduced pressure followed by diluting the concentrated mixture with an extraction solvent to obtain a bilayer aqueous-organic mixture; g) washing the organic layer obtained in step f) with water for at least three times followed by extracting the combined aqueous layer with an extraction solvent; and h) concentrating the combined organic layers obtained in step g), and purifying the crude residue by flash chromatography to afford the halogenated aromatic and / or heteroaromatic compound. wherein the aromatic and / or heteroaromatic compound is selected from the group consisting of (un)substituted aryl, (un)substituted heteroaryl, wherein substituted groupis selected from the group consisting of alkyl, alkoxy, aryloxy, hydroxyl, ester, free amine, and sulfide hydroxyl.

13. The process as claimed in claim 12, wherein the polar solvent of step a) is DMF; the solvent of step e) is methanol; and the extraction solvent of step f) is ethyl acetate.In Re International Application of: COUNCIL OF SCIENTIFIC & INDUSTRIALRESEARCHInternational Application No.: PCT / IN2025 / 050045International Filing Date: January 16, 2025Title: “UPCYCLING OF HALOGENATED POLYMERS TO OBTAIN VALUE ADDEDPRODUCTS”Agent’s file Reference No.: P_W0100735STATEMENT UNDER ARTICLE 19With reference to the search report and written opinion of ISA / IN, the applicant has amended claims to address the novelty and inventive step objections.

1. The Applicant submits that claim 1 has been amended by adding the features of claim 8.

2. The Applicant submits that claim 8 has been deleted accordingly.

3. The Applicant submits that claims have been renumbered accordingly.The Applicant undertakes that no new subject matter has been added in claims and the amended claims do not go beyond disclosure of international application as-filed.STATEMENT UNDER ARTICLE 19 (1 )

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