Microwave-assisted liquefaction of carbohydrates for 5-hydroxymethylfurfural using tungstophosphoric acid encapsulated dendritic fibrous mesoporous silica as a catalyst

Advances in Nano-Functional Materials in Targeted Thrombolytic Drug Delivery

Thrombotic disease has been listed as the third most fatal vascular disease in the world. After decades of development, clinical thrombolytic drugs still cannot avoid the occurrence of adverse reactions such as bleeding. A number of studies have shown that the application of various nano-functional materials in thrombus-targeted drug delivery, combined with external stimuli, such as magnetic, near-infrared light, ultrasound, etc., enrich the drugs in the thrombus site and use the properties of nano-functional materials for collaborative thrombolysis, which can effectively reduce adverse reactions such as bleeding and improve thrombolysis efficiency. In this paper, the research progress of organic nanomaterials, inorganic nanomaterials, and biomimetic nanomaterials for drug delivery is briefly reviewed.

Efficient conversion of carbohydrates into 5-hydroxymethylfurfural using choline chloride-based deep eutectic solvents

In this study, the conversion of monosaccharides to 5-hydroxymethylfurfural (5-HMF) using different deep eutectic solvents (DESs) was investigated in various conditions. Among all the investigated DESs, [ChCl][trichloroacetic acid], based on choline chloride and trichloroacetic acid with the ratio 1:1, showed the highest catalytic activity. A maximum 5-HMF yield was 82 % for 1 h at 100 °C using [ChCl][trichloroacetic acid] as a catalyst from fructose. [ChCl][trichloroacetic acid] could be recovered and reused three times with a slight loss in activity. Our work demonstrated the low-cost and effective method for the synthesis of 5-HMF from carbohydrates.

One Step Catalytic Conversion of Polysaccharides in Ulva prolifera to Lactic Acid and Value-Added Chemicals

The production of lactic acid and value-added chemicals (such as hydroxypropanone, glycolic acid, and formic acid) directly from Ulva prolifera via one-step catalytic process was studied. The effect of different amounts of YCl3-derived catalysts on the hydrothermal conversion of carbohydrates in Ulva prolifera was explored, and the reaction conditions were optimized. In this catalytic system, rhamnose could be extracted from Ulva prolifera and converted in situ into lactic acid and hydroxypropanone at 160 °C, while all the glucose, xylose, and rhamnose were fractionated and completely converted to lactic acid at 220 °C or at a higher temperature, via several consecutive and/or parallel catalytic processes. The highest yield of lactic acid obtained was 31.4 wt% under the optimized conditions. The hydrothermal conversion of Ulva prolifera occurred rapidly (within 10 min) and showed promise to valorize Ulva prolifera.

Preparation of 5-hydroxymethylfurfural using magnetic Fe3O4@SiO2@mSiO2-TaOPO4 catalyst in 2-pentanol

5-Hydroxymethylfurfural (HMF) is one of the most important platform molecules and could be transformed into a variety of fuel additives and high value-added chemicals. Multiple catalyst systems have been developed for the conversion of carbohydrates to HMF, but there are still unavoidable problems, including high temperature and pressure, difficult recovery of solvent, corrosion of equipment, poor catalyst circulation, etc. Herein, a new magnetic Fe3O4@SiO2@mSiO2-TaOPO4 catalyst for the preparation of HMF from fructose in 2-pentanol was developed. The structures of the catalysts were characterized by FT-IR, TSM, EDS, SEM, XRD and VSM. The 2-pentanol solvent is not only conducive to the production of HMF, but also enables the reaction to be carried out at a lower pressure. The highest yield of HMF (85.4%) was obtained using 20 wt% catalyst under 10% substrate concentration (0.5 g of fructose) at 120 °C for 3 h. The catalysts can be easily separated by magnetism. The slight decrease in catalyst activity after 7 cycles was mainly due to the loss of catalyst during the cycle operation. Simultaneously, the total yield of HMF was 51.3% after scale-up to 15 g of fructose, showing the possible industrial application potential of this catalyst system.

Microwave-Assisted Conversion of Carbohydrates

Catalytic conversion of carbohydrates into value-added products and platform chemicals became a trend in recent years. Microwave activation used in the processes of carbohydrate conversion coupled with the proper choice of catalysts makes it possible to enhance dramatically the efficiency and sometimes the selectivity of catalysts. This mini-review presents a brief literature survey related to state-of-the-art methods developed recently by the world research community to solve the problem of rational conversion of carbohydrates, mostly produced from natural resources and wastes (forestry and agriculture wastes) including production of hydrogen, synthesis gas, furanics, and alcohols. The focus is made on microwave technologies used for processing carbohydrates. Of particular interest is the use of heterogeneous catalysts and hybrid materials in processing carbohydrates.

Effect of the Wells–Dawson phosphomolybdic heteropolyacid on the conversion of glucose into glycolic acid

The Wells–Dawson phosphomolybdic heteropolyacid had high activity and selectivity in the epimerization of glucose into mannose and the [2 + 4] retro-aldol reaction of glucose/mannose.

In situ characterization of functional groups of biochar in pyrolysis of cellulose

Heating rate, an important parameter in pyrolysis, not only impacts distribution of pyrolysis products, but also affects evolution of functionality of biochar and further application of the biochar. In this study, an in situ Diffuse Reflection Infrared Fourier Transform Spectra (DRIFTS) technique was used to probe transformation of functional groups of the biochar derived from pyrolysis of cellulose at varied heating rate of 5, 10, 15 and 20 °C/min, aiming to draw an overall picture for the change of functional groups of the biochar versus the heating rate and pyrolysis temperature. The results showed the abundance of -OH, CH and CO experienced a maximum in 410 to 450 °C, depending on the specific heating rates, and then decreased with further increasing temperature via the conversion routes including dehydration, dehydrogenation and cracking. This led to carbonization of the biochar with monotonous increase of abundance of =C-H and CC functionality. Formation of the =C-H had a very close correlation with the removal of -C-H and -OH, especially the -C-H. Cracking of CO was one of the decisive factors for formation of CC. Nevertheless, cracking of C-O-C was much more difficult to be removed than that of CO and -OH, deterring the carbonization and leading to the retainment oxygen in the biochar.