Remarkably Efficient Microwave-Assisted Cross-Metathesis of Lipids under Solvent-Free Conditions

Improving the Barrier and Mechanical Properties of Paper Used for Packing Applications with Renewable Hydrophobic Coatings Derived from Camelina Oil

This study looked at using modified camelina oil to develop sustainable coatings that could replace those derived from petroleum-based materials for use in packaging and other industrial sectors. Solvent-free synthesis of maleic anhydride grafted camelina oil (MCO) was carried out at two different temperatures (200 and 230 °C) to obtain sustainable hydrophobic coating materials for paper substrates. Maleic anhydride grafting of camelina oil was confirmed with attenuated total reflectance-Fourier transform infrared and NMR spectroscopic techniques, and up to 16% grafting of maleic anhydride was achieved, as determined by the titration method. MCO, obtained at different reaction temperatures, was coated onto cellulosic paper and evaluated for its hydrophobicity, mechanical, oxygen, and water vapor barrier properties. Scanning electron microscopy indicated the homogeneous dispersion of coating material onto the paper substrate. MCO-coated papers (MCO-200C paper and MCO-230C paper) provided a water contact angle of above 90° which indicates that the modified oil was working as a hydrophobic coating. Water vapor permeability (WVP) testing of coated papers revealed a reduction in WVP of up to 94% in comparison to the uncoated paper. Moreover, an improved oxygen barrier property was also observed for paper coated with both types of MCO. Analysis of the mechanical properties showed a greater than 70% retention of tensile strength and up to a five-fold increase in elongation at break of coated versus uncoated papers. Overall, the results show that camelina oil, a renewable resource, can be modified to produce environmentally friendly hydrophobic coating materials with improved mechanical and water vapor barrier properties that can serve as a potential coating material in the packaging industry. The results of this research could find applications in the huge paper packaging industries, specially in food packaging.

Revisiting the Potential of Group VI Inorganic Precatalysts for the Ethenolysis of Fatty Acids through a Mechanochemical Approach

The utilization of biobased feedstocks to prepare useful compounds is a pivotal trend in current chemical research. Among a varied portfolio of naturally available starting materials, fatty acids are abundant, versatile substrates with multiple applications. In this context, the ethenolysis of unsaturated fatty acid esters such as methyl oleate is an atom-economical way to prepare functional C10 olefins with a biobased footprint. Despite the existence of a variety of metathesis catalysts for the latter process, there is a lack of readily available, efficient, and inexpensive catalytic systems based on earth-abundant metals (Mo, W) whose preparation does not require sophisticated syntheses and manipulations. Here, a systematic exploration of homogeneous and heterogeneous inorganic Mo, W (oxy)halides shows that MoOCl4, while inactive as a homogeneous species, forms active and selective silica-supported ethenolysis precatalysts able to reach equilibrium conversion of methyl oleate within a few minutes upon activation with SnMe4. Such heterogeneous MoOCl4-based precatalysts were easily accessed through mechanochemical solvent-free procedures and found to contain, upon characterization by elemental analysis and Raman spectroscopy, isolated (≡SiO)Mo(=O)Cl3 units or polymeric silica-supported [-O(≡SiO)nMoCl4-nO-]m (n = 1, 2) complexes depending on the molybdenum loading. The former isolated species exhibited a higher catalytic performance. The developed heterogeneous precatalysts could be applied to the ethenolysis of various substrates, including polyunsaturated fatty acid esters and industrial fatty acid methyl ester (FAME) mixtures from palm oil transesterification.

Inhibition of the Decomposition Pathways of Ruthenium Olefin Metathesis Catalysts: Development of Highly Efficient Catalysts for Ethenolysis

Ruthenium-based Hoveyda-type olefin metathesis catalysts bearing novel rigid spirocyclic alkyl amino carbenes (CAACs) have been developed. They are characterized by exceptional stability toward decomposition through β-elimination and bimolecular pathways, thus enabling unprecedented efficiency in the cross-metathesis of seed oil-derived fatty acid esters with ethylene (ethenolysis). Catalyst loading as low as 100 ppb was applied to the ethenolysis of the model substrate methyl oleate, leading to a remarkable turnover number (TON) of 2.6 million, significantly higher than previously reported (TON 340 000 at 1 ppm and 744 000 at 0.5 ppm catalyst loading). Ethenolysis of methyl esters derived from high oleic sunflower oil and rapeseed oil, readily available on an industrial scale, inexpensive, and renewable feedstocks, was for the first time effectively carried out with 0.5 ppm catalyst loading with TON as high as 964 000.

Valorization of camelina oil to biobased materials and biofuels for new industrial uses: a review

Global environmental pollution is a growing concern, especially the release of carbon dioxide from the use of petroleum derived materials which negatively impacts our environment's natural greenhouse gas level. Extensive efforts have been made to explore the conversion of renewable raw materials (vegetable oils) into bio-based products with similar or enhanced properties to those derived from petroleum. However, these edible plant oils, commonly used for human food consumption, are often not suitable raw materials for industrial applications. Hence, there is an increasing interest in exploring the use of non-edible plant oils for industrial applications. One such emerging oil seed crop is Camelina sativa, generally known as camelina, which has limited use as a food oil and so is currently being explored as a feedstock for various industrial applications in both Europe and North America. Camelina oil is highly unsaturated, making it an ideal potential AGH feedstock for the manufacture of lower carbon footprint, biobased products that reduce our dependency on petroleum resources and thus help to combat climate change. This review presents a brief description of camelina highlighting its composition and its production in comparison with traditional plant oils. The main focus is to summarize recent data on valorization of camelina oil by various chemical means, with specific emphasis on their industrial applications in biofuels, adhesives and coatings, biopolymers and bio-composites, alkyd resins, cosmetics, and agriculture. The review concludes with a discussion on current challenges and future opportunities of camelina oil valorization into various industrial products.

Testing enabling techniques for olefin metathesis reactions of lipophilic substrates in water as a diluent

Olefin metathesis reactions of diverse polyfunctional substrates were conducted in water emulsions using two hydrophobic ruthenium catalysts in the presence of air. Instead of using surfactants to increase the efficiency of the metathesis reaction in water, ultrasound and microwave techniques were tested on a small-scale reaction, whereas conventional heating and mechanical stirring were effective enough to provide high conversion and selectivity on a larger scale. The developed conditions extend known protocols for the aqueous metathesis methodology, utilizing relatively low catalyst loadings and allowing for simple product isolation and purification. The established synthetic protocol was successfully adopted in the large-scale synthesis of a pharmaceutically related product – sildenafil (Viagra) derivative.

•

Sustainable approach for metathesis reaction in water emulsion system on air.

•

Utilization of enabling techniques for boosting metathesis under aqueous conditions.

•

RCM of medically important sildenafil derivative.

Chemical Recycling of Plastics by Microwave-Assisted High-Temperature Pyrolysis

Use of plastics faces much criticism because of its shocking and increasing impact on the environment. But banning plastic will not help the environment. Only appropriate recycling of plastic waste can give satisfying solution. A lab-scale chemical recycling method, in which a mixture of plastic wastes and plant oil is continuously cracked into ethylene, propylene, and other useful chemicals by using microwave-assisted high-temperature pyrolysis, is developed. The method has delivered interesting leads that provide the basis for setting up a new process. Based on the encouraging results, a "drop-in" method for a renewable and circular polymer industry is also proposed. If it is commercially realized, plastic waste and plant oils will be the feedstock for the polymer industry and this industry will become renewable and circular.

Polymers Based on Cyclic Carbonates as Trait d'Union Between Polymer Chemistry and Sustainable CO2 Utilization

Given the large amount of anthropogenic CO₂ emissions, it is advantageous to use CO₂ as feedstock for the fabrication of everyday products, such as fuels and materials. An attractive way to use CO₂ in the synthesis of polymers is by the formation of five-membered cyclic organic carbonate monomers (5CCs). The sustainability of this synthetic approach is increased by using scaffolds prepared from renewable resources. Indeed, recent years have seen the rise of various types of carbonate syntheses and applications. 5CC monomers are often polymerized with diamines to yield polyhydroxyurethanes (PHU). Foams are developed from this type of polymers; moreover, the additional hydroxyl groups in PHU, absent in classical polyurethanes, lead to coatings with excellent adhesive properties. Furthermore, carbonate groups in polymers offer the possibility of post-functionalization, such as curing reactions under mild conditions. Finally, the polarity of carbonate groups is remarkably high, so polymers with carbonates side-chains can be used as polymer electrolytes in batteries or as conductive membranes. The target of this Review is to highlight the multiple opportunities offered by polymers prepared from and/or containing 5CCs. Firstly, the preparation of several classes of 5CCs is discussed with special focus on the sustainability of the synthetic routes. Thereafter, specific classes of polymers are discussed for which the use and/or presence of carbonate moieties is crucial to impart the targeted properties (foams, adhesives, polymers for energy applications, and other functional materials).

Efficient Conversion of Renewable Unsaturated Fatty Acid Methyl Esters by Cross-Metathesis with Eugenol

Cross-metathesis of unsaturated fatty acid methyl esters (methyl oleate (MO), methyl petroselinate (MP), and methyl erucate (ME), obtained from vegetable oils) with eugenol (obtained from clove oil) proceeded under green, mild conditions (in 2-propanol or ethanol at 50 °C) in the presence of a ruthenium-carbene catalyst (called a second-generation Grubbs catalyst). These metathesis reactions proceeded with both high conversion (>90% of MO, MP) and selectivity (>98%) even with low catalyst loading (0.1 mol % Ru).

Microwave-assisted rapid synthesis of a polyether from a plant oil derived monomer and its optimization by Box–Behnken design

In this study, a new strategy for making biopolyethers from plant oil derived monomer (α-olefin) was developed using microwave irradiation, conditions were optimized and compared with a conventional method.

Rapid copolymerization of canola oil derived epoxide monomers with anhydrides and carbon dioxide (CO2)

A rapid synthesis of bio-based polyesters/polycarbonates from canola oil derived monomers and carbon dioxide/anhydrides using microwaves.