Sustainability Assessment of Chemical Processes: Evaluation of Three Synthesis Routes of DMC

This paper suggested multicriteria based evaluation tool to assess the sustainability of three different reaction routes to dimethyl carbonate: direct synthesis from carbon dioxide and methanol, transesterification of methanol and propylene carbonate, and oxidative carbonylation of methanol. The first two routes are CO 2 -based and in a research and development phase, whereas the last one is a commercial process. The set of environmental, social, and economic indicators selected were renewability of feedstock, energy intensity, waste generation, CO 2 balance, yield, feedstock price, process costs, health and safety issues of feedstock, process conditions, and innovation potential. The performance in these indicators was evaluated with the normalized scores from 0 to +1; 0 for detrimental and 1 for favorable impacts. The assessment showed that the transesterification route had the best potential toward sustainability, although there is still much development needed to improve yield. Further, the assessment gave clear understanding of the main benefits of each reaction route, as well as the major challenges to sustainability, which can further aid in orienting development efforts to key issues that need improvement. Finally, it was concluded that a multicriteria analysis such as the one presented in this paper was a viable method to be used in the process design stage

Developing Standard Treatment Workflows—way to universal healthcare in India

Primary healthcare caters to nearly 70% of the population in India and provides treatment for approximately 80–90% of common conditions. To achieve universal health coverage (UHC), the Indian healthcare system is gearing up by initiating several schemes such as National Health Protection Scheme, Ayushman Bharat, Nutrition Supplementation Schemes, and Inderdhanush Schemes. The healthcare delivery system is facing challenges such as irrational use of medicines, over- and under-diagnosis, high out-of-pocket expenditure, lack of targeted attention to preventive and promotive health services, and poor referral mechanisms. Healthcare providers are unable to keep pace with the volume of growing new scientific evidence and rising healthcare costs as the literature is not published at the same pace. In addition, there is a lack of common standard treatment guidelines, workflows, and reference manuals from the Government of India. Indian Council of Medical Research in collaboration with the National Health Authority, Govt. of India, and the WHO India country office has developed Standard Treatment Workflows (STWs) with the objective to be utilized at various levels of healthcare starting from primary to tertiary level care. A systematic approach was adopted to formulate the STWs. An advisory committee was constituted for planning and oversight of the process. Specialty experts' group for each specialty comprised of clinicians working at government and private medical colleges and hospitals. The expert groups prioritized the topics through extensive literature searches and meeting with different stakeholders. Then, the contents of each STW were finalized in the form of single-pager infographics. These STWs were further reviewed by an editorial committee before publication. Presently, 125 STWs pertaining to 23 specialties have been developed. It needs to be ensured that STWs are implemented effectively at all levels and ensure quality healthcare at an affordable cost as part of UHC

Direct synthesis of dimethyl carbonate from methanol and carbon dioxide: a thermodynamic and experimental study

The direct synthesis of dimethyl carbonate (DMC) from carbon dioxide and methanol is an atom economic, green and promising process. The present work focuses on this process using calcined hydrotalcite (CHT) supported on hexagonal mesoporous silica (HMS) as a catalyst and phosphonium based ionic liquid (IL) as a promoter. Phosphonium based ionic liquids are good solvents for carbon dioxide and are better alkali promoters. Different modified Keggin type cesium modified heteropoly acids (HPA) supported on HMS were also used as catalysts, which give good comparison between dual site catalysts with altered acidity or/and basicity. The conversion and selectivity were measured as a function of concentration of reactants, catalyst and temperature. The experimental results were compared with the thermodynamic calculations and simulated results. Kinetic model was developed by proposing a reaction mechanism. Sustainability of the process was justified by using a heterogeneous catalyst and by avoiding the use of harmful organic solvents in the presence of an ionic liquid with supercritical CO<SUB>2</SUB>

Selectivity engineering of O-methylation of hydroxybenzenes with dimethyl carbonate using ionic liquid as catalyst

Phenolic ethers are useful commercial entities which have been traditionally produced via polluting routes that could be replaced by benign catalytic processes. In the current work, O-methylation of mono-, di- and tri-hydroxy benzenes (phenolics), namely, phenol, catechol and pyrogallol, has been studied with dimethyl carbonate (DMC) as the etherification agent cum solvent in the presence of a phosphonium ionic liquid as catalyst. The co-products methanol and CO<SUB>2</SUB> could be recycled to make DMC. The catalyst is recycled and thus the overall process is a green process. Ionic liquids possess many useful attributes and can be used as solvents and multi-functional catalysts, and some are amenable to recycling and reuse using clever strategies. Two different types of phosphonium-based ionic liquids were used – one group containing the trihexyl (tetradecyl) cation such as trihexyl (tetradecyl) phosphonium chloride (PC), trihexyl (tetradecyl) phosphonium bromide (PB), trihexyl (tetradecyl) phosphonium decanoate (PD), trihexyl (tetradecyl) phosphonium hexafluoro phosphate (HFP), and another symmetric reference containing the tetrabutyl phosphonium cation (tetrabutyl phosphonium bromide (TBPB)) – and were evaluated in the O-methylation of phenol, catechol and pyrogallol with DMC to the corresponding ethers. Depending on the number of hydroxyl groups on the benzene ring, different mono- and poly-ethers could be produced by using suitable process conditions such as molar ratio, catalyst, temperature and time. All of these intermediate and final ethers have different applications. Trihexyl (tetradecyl) phosphonium bromide (PB) was the best catalyst. Effects of various parameters on the rate of reaction, conversion and yield were studied including speed of agitation, catalyst concentration and reusability, reactant concentration and temperature. The best operating conditions were 200 °C, a 1 : 6 mole ratio of reactant to DMC, and trihexyl (tetradecyl) phosphonium bromide (PB) as catalyst. A reaction mechanism is proposed and discussed to deduce the kinetics

Direct synthesis of formic acid from carbon dioxide and hydrogen: a thermodynamic and experimental study using poly-urea encapsulated catalysts

The present work is concerned with direct hydrogenation of CO2 to formic acid which takes into account thermodynamic feasibility and experimental studies. Poly-urea encapsulated catalysts were explored and the effect of ionic liquids under supercritical conditions was examined. The monometallic and bimetallic catalysts were prepared, characterized, screened for the hydrogenation of CO2 and also compared with a commercially available poly-urea–Pd catalyst. The effect of reaction temperature, type of the catalyst, promoter, pressure and molar ratio of the feed (H2/CO2) on the yield of formic acid has been studied and discussed in order to maximize the formation of formic acid. The highest yield of formic acid obtained in terms of turn-over frequency (TOF) was 11,900 h−1 at a total pressure of 144 bar, temperature of 70 °C, mole ratio (H2/CO2) of 1, catalyst (poly urea encapsulated Ru) loading of 0.04 g/cm3 and 3.12 × 10−5 mol/cm3 of ionic liquid (trihexyl (tetradecyl) phosphonium chloride)

Sustainability assessment of chemical processes: evaluation of three synthesis routes of DMC

This paper suggested multicriteria based evaluation tool to assess the sustainability of three different reaction routes to dimethyl carbonate: direct synthesis from carbon dioxide and methanol, transesterification of methanol and propylene carbonate, and oxidative carbonylation of methanol. The first two routes are CO2-based and in a research and development phase, whereas the last one is a commercial process. The set of environmental, social, and economic indicators selected were renewability of feedstock, energy intensity, waste generation, CO2 balance, yield, feedstock price, process costs, health and safety issues of feedstock, process conditions, and innovation potential. The performance in these indicators was evaluated with the normalized scores from 0 to +1; 0 for detrimental and 1 for favorable impacts. The assessment showed that the transesterification route had the best potential toward sustainability, although there is still much development needed to improve yield. Further, the assessment gave clear understanding of the main benefits of each reaction route, as well as the major challenges to sustainability, which can further aid in orienting development efforts to key issues that need improvement. Finally, it was concluded that a multicriteria analysis such as the one presented in this paper was a viable method to be used in the process design stage

Developing and testing a tool for sustainability assessment in an early process design phase:case study of formic acid production by conventional and carbon dioxide-based routes

Abstract This paper suggests a ‘Sustainability Assessment Tool’ that can be used in early design phases of production processes. “Green Chemistry” principles were considered as a baseline when proposing the sustainability indicators. European chemicals regulations and databases were also applied and used as a baseline in chemicals hazards assessment. The tool is an excel based checklist, with multiple choice answers that are scored based on their severity of impact. This Sustainability Assessment Tool was tested by comparing two formic acid production routes. It is proposed that using the tool as a guideline in the early stages of a chemical process design can provide competitive advantages in research as it provides guidance on the critical target areas of the process that should be further developed. This can further guide researchers and engineers through the piloting and manufacturing stages. In addition it is also expected that the suggested sustainability assessment tool can be used as an educating purpose to foster sustainability in process design work during all the design stages