The synthesis of polymers using elemental sulphur as a chemical agent has been studied in relation to the worldwide overproduction of cyclo-octasulphur. Herein, the mechanisms of the processes leading to the inclusion of elemental sulphur into macromolecules have been reviewed and the main methods for reduction of the reaction temperature required for the S₈ ring opening have been shown. Approaches to the activation of cyclo-octasulphur in the synthesis and macromolecule cross-linking reactions were discussed in the context of finding the chemical agents and conditions that satisfy the principles of green chemistry.

Global enhancement of crop yield is achieved using chemical fertilizers; however, agro-economy is affected due to poor nutrient uptake efficacy (NUE), which also causes environmental pollution. Encapsulating urea granules with hydrophobic material can be one solution. Additionally, the inverse vulcanized copolymer obtained from vegetable oils are a new class of green sulfur-enriched polymer with good biodegradation and better sulfur oxidation potential, but they possess unreacted sulfur, which leads to void generations. In this study, inverse vulcanization reaction conditions to minimize the amount of unreacted sulfur through response surface methodology (RSM) is optimized. The copolymer obtained was then characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). FTIR confirmed the formation of the copolymer, TGA demonstrated that copolymer is thermally stable up to 200 °C temperature, and DSC revealed the sulfur conversion of 82.2% (predicted conversion of 82.37%), which shows the goodness of the model developed to predict the sulfur conversion. To further maximize the sulfur conversion, 5 wt% diisopropenyl benzene (DIB) as a crosslinker is added during synthesis to produce terpolymer. The urea granule is then coated using terpolymer, and the nutrient release longevity of the coated urea is tested in distilled water, which revealed that only 65% of its total nutrient is released after 40 days of incubation. The soil burial of the terpolymer demonstrated its biodegradability, as 26% weight loss happens in 52 days of incubation. Thus, inverse vulcanized terpolymer as a coating material for urea demonstrated far better nutrient release longevity compared with other biopolymers with improved biodegradation; moreover, these copolymers also have potential to improve sulfur oxidation.

The new initiator of the polymerization of acrylamide, leading to the formation of crosslinked polyacrylamide, was discovered. The structure of the synthesized polyacrylamide was characterized by XRD, ¹H NMR, and ¹³C NMR spectroscopy. It was shown that 1,3-dimethylimidazolium (phosphonooxy-)oligosulphanide is able to initiate radical polymerization under drying aqueous solutions of acrylamide, even at room temperature. According to XRF data, the synthesized polyacrylamide gel contains 0.28 wt% of sulphur. The formed polymer network has a low crosslinking density and a high equilibrium degree of swelling. The swelling rate of polyacrylamide gel in water corresponds to the first order kinetic equation with the rate constant 6.2 × 10⁻² min⁻¹. The initiator is promising for combining acrylamide polymerization with the processes of gel molding and drying.

The review considers the current ideas of a relatively new field of "green chemistry" in the field of chemical processing of renewable natural plant raw materials. For a number of processes, the ways, methods and some technological aspects of obtaining new compounds and reagent systems, biodegradable compositions and "green chemistry" products that are in demand in various sectors of the economy, industry and life support of society are shown. The article presents the results of the analysis of Russian and world reserves of forest resources according to authoritative modern sources and proposals for their conservation and restora-tion. The problems of biorefiling of plant raw materials are described, one of which is the val-orization of lignin-the aromatic component of the chemical composition of wood. It is pro-posed to obtain biodegradable systems and compositions based on the by-product of wood processing lignosulfonate of a neutral production method characterized by a high content of polysaccharides in the hemicellulose of the carbohydrate part of wood after the separation of cellulose. The ways of using modified cellulose products as inhibitors of salt deposition and gas hydrate formation, and the areas of their application in oilfield chemistry are shown. Lig-nin and other components of plant resources have long been the basis of various classes of fi-bers of natural origin, including plant and animal origin, artificial fibers. In the sector of cre-ating materials with new properties that have a wide range of practical applications, the review describes the production of PLA polylactide synthesized from lactic acid as a modern alterna-tive to many synthetic polymers obtained from refined petroleum products. For the products of the interaction of ammonium lactate and N-butyl alcohol, a kinetic model for the production of butyl lactate, an intermediate product of green chemistry, is described. The results of the study of a specific class of compounds – ionic liquids – traditionally considered as so-called "green solvents" are presented. An approach to the creation of a mathematical model by calculating the adsorption characteristics for evaluating the effectiveness of systems and composites based on biodegradable polymers in the direction of "green chemistry" is proposed.

Interaction of 1,3-dimethylimidazolium dimethylphosphate and elemental sulfur synthesized a new initiator of polymerization of formaldehyde, opening the possibility of its implementation in accordance with the principles of Green chemistry. The possibility of fast oligomerization of formaldehyde in an aqueous medium with the formation of insoluble products, the structure of which is determined by FTIR, MALDI-TOF, ¹H NMR, ¹³C NMR, HSQC and HMBC spectroscopy, is shown. It was found that (phosphonooxy-)oligosulfanide anion initiates formaldehyde oligomerization by anionic mechanism with chain termination due to interaction with water. It was shown that the synthesized formaldehyde oligomers retain resistance to degradation up to a temperature of 443 K, and then slowly thermally decompose to a temperature of 513 K, above which the rate of thermal degradation increases significantly. GRAPHICAL ABSTRACT