Hydrogenation of Tetralin over Supported Ni and Ir Catalysts

Selective hydrogenation and ring opening (SRO) of tetrahydronaphthalene (tetralin) was studied over nickel and iridium supported catalysts in the context of the removal of polynuclear aromatics from diesel fuel. The tetralin hydrogenation was carried out in a fixed-bed reactor at 270 ∘ C, using H 2 pressure of 30 bars, WHSV of 2.3 h −1 , and H 2 /feed molar ratio of 40; the resultant products were analyzed by GC and GC-MS. The Ir/SiO 2 catalyst gave 85% of tetralin conversion and 75.1% of decalin products selectivity whereas Ni/SiO 2 catalyst showed an unprecedented high catalytic performance with 88.3% of tetralin conversion and 93% of decalin products selectivity. The catalysts were characterized by using different characterization techniques such as XRD, TPR, and HR-TEM to know the physicochemical properties as well as active sites in the catalysts

World review of capture fisheries and aquaculture insurance 2022

This world review of capture fisheries and aquaculture insurance presents the findings of five regional and four national reports conducted in 2020. An estimated 450 000 fishing vessels worldwide are covered by marine hull insurance. Nearly all of the estimated 67 800 large-scale industrial fishing vessels are covered by marine hull insurance, as well as 50–60 percent of the estimated 430 000 semi-industrial fishing vessels. However, over 95 percent of the 2.3 million motorized small-scale fishing vessels operate uninsured. Most small-scale fishers do not have access to adequate insurance services. Between 2009 and 2019, underwriting experiences in fishing vessel insurance were generally reported as “Good”. What is more, access to accident, life and health insurance services for crew on fishing vessels and small-scale fishers in developing countries has improved in recent years. In 2020, the number of aquaculture insurance policies in force was estimated at over 40 000 worldwide, with China and Indonesia the largest markets for this type of insurance. While large-scale aquaculture producers are well served by the insurance industry, the provision of insurance is inadequate for mediumand small-scale farmers, particularly in Asia. Underwriting experiences for aquaculture stock mortality insurance were reported as “Good” to “Very good” (40 percent), or “Neutral” (36 percent). The insurance industry has consolidated the market and increased profitability in aquaculture insurance. This world review contains information on the capture fisheries and aquaculture insurance market, the prevailing underwriting practices, perils covered, policies in force, risk management and claim handling procedures. Finally, it offers a series of recommendations for increasing insurance service provision to the fisheries and aquaculture industries

Upgrade of Biomass-Derived Levulinic Acid via Ru/C-Catalyzed Hydrogenation to γ‑Valerolactone in Aqueous−Organic−Ionic Liquids Multiphase Systems

A liquid triphase system made by an aqueous phase, an organic phase, and an ionic liquid was designed and applied to the catalytic hydrogenation/dehydration of biomass-derived levulinic acid to γ-valerolactone. This paper demonstrates that, by operating at 100−150 °C and 35 atm of H2, both in the presence of Ru/C or of a homogeneous Ru precursor, the use of the triphase system designed to match the investigated reaction allows the following: (1) to obtain up to quantitative conversions and 100% selectivity toward the desired product; (2) to recover the product by simple phase separation; and (3) to preserve the catalyst activity for in situ recycles without loss of metal. Globally the investigated reaction proves the concept that a cradle-to-grave approach to the design of a catalytic reaction system can improve the global sustainability of a chemical transformation by improving efficiency, product isolation, and catalyst recycle

Hydrogenation of Tetralin over Supported Ni and Ir Catalysts

Selective hydrogenation and ring opening (SRO) of tetrahydronaphthalene (tetralin) was studied over nickel and iridium supported catalysts in the context of the removal of polynuclear aromatics from diesel fuel. The tetralin hydrogenation was carried out in a fixed-bed reactor at 270°C, using H2 pressure of 30 bars, WHSV of 2.3 h−1, and H2/feed molar ratio of 40; the resultant products were analyzed by GC and GC-MS. The Ir/SiO2 catalyst gave 85% of tetralin conversion and 75.1% of decalin products selectivity whereas Ni/SiO2 catalyst showed an unprecedented high catalytic performance with 88.3% of tetralin conversion and 93% of decalin products selectivity. The catalysts were characterized by using different characterization techniques such as XRD, TPR, and HR-TEM to know the physicochemical properties as well as active sites in the catalysts

A Robust and Highly Selective Catalytic System of Copper-Silica Nanocomposite and 1-Butanol in Fructose Hydrogenation to Mannitol

We report for the first time the selective production of mannitol, a low-calorie sweetener and an important pharmaceutical ingredient, from fructose using Cu-SiO(2)nanocomposite as catalyst and 1-butanol as solvent. When compared with water and ethanol, a lower fructose solubility was achieved in 1-butanol, which caused a lower fructose conversion and higher mannitol selectivity by reducing formation of side products. Among various Cu-based catalysts in 1-butanol, Cu(80)-SiO(2)nanocomposite gave an unprecedented mannitol (83 %) and sorbitol (15 %) yield at 120 degrees C, 35 bar H-2, and 10 h reaction time. More importantly, this catalyst did not show any Cu leaching and its physicochemical properties were maintained after liquid-phase fructose hydrogenation whereas other Cu-based catalysts such as Cu(32)-Cr2O and Cu(66)-ZnO did show significant leaching of Cu and Cr. Thus, Cu(80)-SiO(2)nanocomposite and 1-butanol are regarded as a robust and highly efficient catalytic system for the selective hydrogenation of fructose to mannitol. Also, density functional theory calculations supported that in addition to the stable initial structure of adsorbed fructose, the mannitol pathway was more thermodynamically favorable than the sorbitol pathway. Notably, the highly pure mannitol (99 %) could be recovered from the sorbitol-containing 1-butanol solution by simple filtration. Therefore, the present protocol is a novel and effective method to produce pure mannitol from fructose in both an environmental and an industrial context

A highly efficient hydrotalcite/1-butanol catalytic system for production of the high-yield fructose crystal from glucose

Catalytic isomerization of glucose to fructose is a key step for the synthesis of bioplastics and biofuels as well as sweeteners. In this study, a record fructose yield of greater than 50% with selectivity exceeding 80% was obtained from glucose concentration of 10 wt.% by adopting a 1-butanol/hydrotalcite catalytic system. In this novel process, Mg2+ leaching from hydrotalcite, which is an important issue when utilizing hydrotalcite for glucose isomerization in aqueous solution, was negligible during the reaction. NMR study confirmed that the absence of deuterium at the C-1 position of the fructose product as well as C-2 position of glucose-2-d clearly supports the base-catalyzed deprotonation of the C-2 position in glucose. Also, DFT calculations supported the selective formation of fructose from glucose over hydrotalcite surface in 1-butanol than other solvents. Notably, after glucose isomerization the highly-pure glucose (91%) and fructose crystals (95%) were recovered easily from 1-butanol solvent by subsequent cooling and filtration without requiring chromatographic separation. Therefore, the hydrotalcite/1-butanol catalytic system is simple, inexpensive, and green process for the high-yield fructose production from glucose when compared with current industrial procedures that rely on enzymatic isomerization reactions and chromatographic separations

Design of a heterogeneous catalytic process for the continuous and direct synthesis of lactide from lactic acid

We present a continuous one-step reaction pathway for optically pure lactide under atmospheric conditions based on a novel SnO2-SiO2 nanocomposite catalyst. The new heterogeneous catalytic system gave a record high lactide yield of 94% with almost 100% enantioselectivity and long-term stability (>2500 h) from L-lactic acid.close