Novel Process for Conversion of CO₂ to Dimethyl Carbonate using Catalytic Membrane Reactors

Dimethyl carbonate (DMC) receives much attention due to its versatile use, low toxicity and fast biodegradability. Various ‘green’ production routes are explored and developed to replace the classic and rather toxic synthesis of DMC via phosgene. The direct DMC synthesis route – from CO2 and methanol – is one of the most interesting options for the chemical industry, but this is hindered by the limited chemical equilibrium. This work describes the simulation of a novel process for DMC using PSE and PI methods. A membrane reactor plays the central role, as it continuously removes the water by-product, in order to overcome the equilibrium limitations. Aspen Plus simulations were carried out for a DMC process (20 kt/yr) and over 99 wt% purity of the DMC product. Due to the incomplete conversion in the membrane reactor, the DMC concentration in the reactor effluent is rather low hence the purification of this diluted stream leads to large recycles and requires large size equipment and a considerable amount of energy

Techno-economic evaluation of the direct conversion of CO2 to dimethyl carbonate using catalytic membrane reactors

The production of dimethyl carbonate (DMC) caught more interest in the past decades due to its versatile use (e.g. as fuel additive), low toxicity and fast biodegradability. Different ‘green’ production routes are being developed to replace the conventional and rather toxic production of DMC via phosgene. The direct conversion of CO2 and methanol toward DMC is an environmental and economically interesting production route for the chemical industry. This work describes the process design of the direct conversion of CO2 to dimethyl carbonate, providing a valuable insight and a better understanding of the process limitations. In this design, membrane reactors are used for continuous removal of water by-product, in order to overcome the equilibrium limitations. The rigorous Aspen Plus simulations show that even when using an excess of methanol, the attainable conversion is low and the DMC concentration in the reactor effluent is less than 1.5 mol%. Purifying this diluted stream to the desired concentrations demands large size equipment and a substantial amount of energy (13.61 kWh/kg DMC) resulting in high investment and utility costs, thus making the process not profitable. The focus for new membrane reactors could be on the selective removal of DMC (instead of water) from the reaction area to allow for a more concentrated DMC stream

Techno-economic evaluation of the direct conversion of CO₂ to dimethyl carbonate using catalytic membrane reactors

The production of dimethyl carbonate (DMC) caught more interest in the past decades due to its versatile use (e.g. as fuel additive), low toxicity and fast biodegradability. Different 'green' production routes are being developed to replace the conventional and rather toxic production of DMC via phosgene. The direct conversion of CO2 and methanol toward DMC is an environmental and economically interesting production route for the chemical industry.This work describes the process design of the direct conversion of CO2 to dimethyl carbonate, providing a valuable insight and a better understanding of the process limitations. In this design, membrane reactors are used for continuous removal of water by-product, in order to overcome the equilibrium limitations. The rigorous Aspen Plus simulations show that even when using an excess of methanol, the attainable conversion is low and the DMC concentration in the reactor effluent is less than 1.5mol%. Purifying this diluted stream to the desired concentrations demands large size equipment and a substantial amount of energy (13.61kWh/kg DMC) resulting in high investment and utility costs, thus making the process not profitable. The focus for new membrane reactors could be on the selective removal of DMC (instead of water) from the reaction area to allow for a more concentrated DMC stream

Renal cell carcinoma-associated antigen G250 encodes a naturally processed epitope presented by human leukocyte antigen-DR molecules to CD4(+) T lymphocytes.

We previously identified an HLA-A2.1-restricted epitope within the RCC-associated antigen G250 that is recognized by CTLs. Using DCs of healthy individuals, which were loaded with overlapping 20 mer G250-derived peptides, we here report the induction of CD4(+) T cells that recognize the G250 peptide of amino acids 249-268. Moreover, naturally processed G250 protein is readily recognized by these G250-specific CD4(+) T cells in the context of HLA-DR molecules. Interestingly, peptide G250:249-268 overlaps the previously identified HLA-A2.1-restricted G250 epitope recognized by CTLs. These data and the high prevalence of G250 in RCC patients make peptide G250:249-268 a potential target in peptide-based vaccines to induce both CD4(+) and CD8(+) T-cell responses in patients