Furfural production by continuous reactive extraction in a milireactor under the Taylor Flow regime

This study demonstrates the use of a milireactor as intensified technology for the continuous production of furfural via acid dehydration of xylose in a bi-phasic media. Very rapid extraction of furfural, aided by fast mass transfer rates, is key to prevent furfural subsequent degradation. Thus, by operating at elevated temperatures (i.e., 150-190 οC), it is possible to maintain high furfural selectivity (ca. 70%) at high xylose conversion (ca. 80%) and very short residence times (up to 2.5 min). A reaction mechanism is proposed based on the observed conversion-selectivity trends, and on the analysis of product distribution. The contribution of humins to the carbon balance is remarkably low due to the high furfural extraction rates achieved in the millireactor. Through first-principle reactor modeling, we further demonstrate the potential of combining intensified reactor technologies with the extractive synthesis of furfural, and we show that solvent optimization will be crucial to boost furfural selectivity above 80%

Sequential and in situ extraction of furfural from reaction mixture and effect of extracting agents on furfural degradation

Furfural is a platform chemical that can be obtained from renewable resources. It can be produced by acid-catalyzed dehydration of xylose. Currently, the furfural yield is relatively low due to side reactions (degradation of furfural). The furfural yield can be improved by rapidly and continuous removal of the furfural from the reaction mixture (in-situ extraction), preventing further furfural degradation. In this work, the (in-situ) extraction of furfural from the reaction mixture using different organic solvents and hydrophobic deep eutectic solvents is investigated. First, the distribution coefficients of furfural in various organic solvents were determined. It was found that extracting agents containing phenol-groups showed the highest distribution ratios. Thereafter, the acid-catalyzed degradation of furfural in the presence of the different solvents was assessed. Addition of organic solvents or hydrophobic deep eutectic solvents resulted in a significant decrease in furfural degradation compared to the blank and the benchmark. Finally, in-situ extraction with the different extracting agents was performed. The xylose conversion was not influenced by solvent addition, whereas the furfural yields were significantly higher compared to the blank experiment, even when low amounts of extracting agents were applied. This was explained by the limited co-extraction of the acid to the organic phase, preventing further contact/reaction between the furfural and the acid. Hence, organic solvents and hydrophobic deep eutectic solvents can be promising in-situ extracting agents for the removal of furfural from biorefinery processes

Sequential and in situ extraction of furfural from reaction mixture and effect of extracting agents on furfural degradation

Furfural is a platform chemical that can be obtained from renewable resources. It can be produced by acid-catalyzed dehydration of xylose. Currently, the furfural yield is relatively low due to side reactions (degradation of furfural). The furfural yield can be improved by rapidly and continuous removal of the furfural from the reaction mixture (in-situ extraction), preventing further furfural degradation. In this work, the (in-situ) extraction of furfural from the reaction mixture using different organic solvents and hydrophobic deep eutectic solvents is investigated. First, the distribution coefficients of furfural in various organic solvents were determined. It was found that extracting agents containing phenol-groups showed the highest distribution ratios. Thereafter, the acid-catalyzed degradation of furfural in the presence of the different solvents was assessed. Addition of organic solvents or hydrophobic deep eutectic solvents resulted in a significant decrease in furfural degradation compared to the blank and the benchmark. Finally, in-situ extraction with the different extracting agents was performed. The xylose conversion was not influenced by solvent addition, whereas the furfural yields were significantly higher compared to the blank experiment, even when low amounts of extracting agents were applied. This was explained by the limited co-extraction of the acid to the organic phase, preventing further contact/reaction between the furfural and the acid. Hence, organic solvents and hydrophobic deep eutectic solvents can be promising in-situ extracting agents for the removal of furfural from biorefinery processes

Human Homolog of Yeast Pre-mRNA Splicing Gene, PRP31, Underlies Autosomal Dominant Retinitis Pigmentosa on Chromosome 19q13.4 (RP11)

7 páginas, 4 figuras, 1 tabla.-- et al.We report mutations in a gene (PRPF31) homologous to Saccharomyces cerevisiae pre-mRNA splicing gene PRP31 in families with autosomal dominant retinitis pigmentosa linked to chromosome 19q13.4 (RP11; MIM 600138). A positional cloning approach supported by bioinformatics identified PRPF31 comprising 14 exons and encoding a protein of 499 amino acids. The level of sequence identity to the yeast PRP31 gene indicates that PRPF31 is also likely to be involved in pre-mRNA splicing. Mutations that include missense substitutions, deletions, and insertions have been identified in four RP11-linked families and three sporadic RP cases. The identification of mutations in a pre-mRNA splicing gene implicates defects in the splicing process as a novel mechanism of photoreceptor degeneration.This work was funded by MRC grants G0000011 and G9301094, the Wellcome Trust Grant (043006 and 041275), the Foundation for Fighting Blindness (USA), the British Retinitis Pigmentosa Society, and Fight For Sight. M.P. is supported by a Marie Curie Fellowship and C.C. is funded by the European Union.Peer reviewe

Mutations in TOPORS Cause Autosomal Dominant Retinitis Pigmentosa with Perivascular Retinal Pigment Epithelium Atrophy

We report mutations in the gene for topoisomerase I–binding RS protein (TOPORS) in patients with autosomal dominant retinitis pigmentosa (adRP) linked to chromosome 9p21.1 (locus RP31). A positional-cloning approach, together with the use of bioinformatics, identified TOPORS (comprising three exons and encoding a protein of 1,045 aa) as the gene responsible for adRP. Mutations that include an insertion and a deletion have been identified in two adRP-affected families—one French Canadian and one German family, respectively. Interestingly, a distinct phenotype is noted at the earlier stages of the disease, with an unusual perivascular cuff of retinal pigment epithelium atrophy, which was found surrounding the superior and inferior arcades in the retina. TOPORS is a RING domain–containing E3 ubiquitin ligase and localizes in the nucleus in speckled loci that are associated with promyelocytic leukemia bodies. The ubiquitous nature of TOPORS expression and a lack of mutant protein in patients are highly suggestive of haploinsufficiency, rather than a dominant negative effect, as the molecular mechanism of the disease and make rescue of the clinical phenotype amenable to somatic gene therapy