Applications of hydrothermal electrolysis for conversion of 1-butanol in wastewater treatment

Hydrothermal electrolysis of organic compound in the presence of electrolyte was conducted for a woody biomass model compound. The reaction behavior of 1-butanol as a woody biomass model compound was studied in subcritical conditions at 200-250 °C and 8-12 MPa with a batch autoclave. The autoclave volume was 500 mL and equipped system with agitation stirrer, electric current control, electric heating and temperature control and a pressure gauge. The chemical species in aqueous products were identified by gas chromatography mass spectrometry (GC-MS) and quantified using gas chromatography flame ionization detector (GC-FID). The gaseous products were analyzed by gas chromatography with a thermal conductivity detector (GC-TCD). The effects of reaction temperature, pressure and applied constant current on the conversion process of 1-butanol were presented. The main products from the conversion of 1-butanol were butanal, butyric acid, hydrogen and carbon dioxide. Additionally, the values of reaction rate constant for butanal and butyric acid formation were calculated at 200 and 250 °C by kinetic study.     

Recovery of Phenol through the Decomposition of Tar under Hydrothermal Alkaline Conditions

Decomposition of the tar residue from oil distillation was carried out under hydrothermal conditions using a batch reactor at 623–673 K and 25–40 MPa, with and without K₂CO₃ as a catalyst. The reaction scheme for tar decomposition was determined as follows: the liquefaction and dissolution process of tar occur first and then intermediate chemical compounds are transformed into lighter molecular weight species. The presence of K₂CO₃ activates the dissociation of molecular hydrogen to facilitate hydrogenation reactions. The main products from the decomposition of tar were phenol, biphenyl, diphenylether (DPE), and diphenylmethane (DPM). These results indicate that hydrolysis was important in the cleavage of the macromolecular structure of tar under both catalytic and non‐catalytic hydrothermal conditions. This method can be developed for efficient tar liquefaction to generate high yields of valuable chemicals in an environmentally friendly way.     

Micronization of curcumin with biodegradable polymer by supercritical anti-solvent using micro swirl mixer

Curcumin is a hydrophobic polyphenol compound exhibiting a wide range of biological activities such as anti-inflammatory, anti-bacterial, anti-fungal, anti-carcinogenic, anti-human immunodeficiency virus, and anti-microbial activity. In this work, a swirl mixer was employed to produce the micronized curcumin with polyvinylpyrrolidone (PVP) by the supercritical anti-solvent process to improve the bioavailability of curcumin. The effects of operating parameters such as curcumin/PVP ratio, feed concentration, temperature, pressure, and CO₂ flow rate were investigated. The characterization and solubility of particles were determined by using scanning electron microscopy, Fourier Transform Infrared spectroscopy, and ultra-violet-visible spectroscopy. The result shows that the optimal condition for the production of curcumin/PVP particles is at curcumin/PVP ratio of 1:30, feed concentration of 5 mg·mL⁻¹, temperature of 40 °C, pressure of 15 MPa, and CO₂ flow rate of 15 mL·min⁻¹. Moreover, the dissolution of curcumin/PVP particles is faster than that of raw curcumin.     

Selective conversion of glucose into lactic acid and acetic acid with copper oxide under hydrothermal conditions

Biomass as a source for chemicals production attracts growing attention due to the decreasing storage of fossil fuels and global warming caused by emission of CO₂. In this study, conversion of glucose with copper oxide (CuO) was studied under alkaline hydrothermal conditions using a batch reactor and continuous flow reactor. CuO, as an oxidant, greatly improves the yields of lactic acid (LA) and acetic acid from glucose and was reduced into Cu₂O and Cu. Selective production of LA with the highest yield of 59% and acetic acid with the highest yield of 32% can be achieved by controlling reaction time, temperature, and addition of CuO. A possible mechanism of conversion of glucose with CuO was proposed. © 2012 American Institute of Chemical Engineers AIChE J, 59: 2096–2104, 2013     

Extraction of β–glucan by hydrothermal liquidization of barley grain in a semi-batch reactor

Subcritical water is a natural and green way for extraction of plant biomass components. Here, subcritical water was employed as a media to extract β–glucan from barley (Hordeum vulgare L.) at 130–170°C and 10 MPa. MALDI TOF–MS revealed that main massed peaks of water soluble products were distributed at 500-2900 m/z with a peak to peak mass difference of 162 m/z, consistent with the repeating unit of β–glucan. At 170°C, all amount of water soluble β–glucan has been extracted. Next, the liquid fraction products were atomized directly to produce microsphere particles.     

Generation of multihollow structured poly(methyl methacrylate) fibers by electrospinning under pressurized CO2

Electrospinning is one of the simple techniques for the production of polymer nano‐microfibers. In this study, hollow fibers from poly(methyl methacrylate) (PMMA) were formed by electrospinning under pressurized carbon dioxide (CO₂) in a single processing step. The experiments were conducted at temperatures and pressures in the range 27–37°C and 4–6 MPa, respectively. At 5 MPa, CO₂ seemed to have enough affinity to dissolve a portion of dichloromethane (DCM) to assist its evaporation. Under subcritical CO₂, electrospun products with hollow core fibers having diameters of 4–16 μm were generated. The results confirmed that the change of operating parameters had a strong influence on the morphologies (crack or hollows) of the electrospun products. This study demonstrated that this process offers the possibility that electrospinning under pressurized CO₂ will become an essential and useful method for the generation of polymer structures with hollow interiors. POLYM. ENG. SCI., 56:752–759, 2016. © 2016 Society of Plastics Engineers     

Thermal isomerization of (all-E)-lycopene and separation of the Z-isomers by using a low boiling solvent: Dimethyl ether

Thermal isomerization of (all-E)-lycopene and the separation of generated Z-isomers were conducted using a low boiling solvent, dimethyl ether (DME). Because of the low boiling point (–24.8°C), DME is easily separated from lipids and other residues and is extremely low residual. The efficiency of thermal Z-isomerization of (all-E)-lycopene in DME was almost equivalent to using hexane. The thermally generated lycopene Z-isomers were separated by utilizing the solubility differences among lycopene isomers and a characteristic of DME that allows the solubility of compounds to be controlled by changing the temperature. Finally, a lycopene mixture containing 72.0% Z-isomers was obtained from (all-E)-lycopene.     

Conversion of biomass model compound under hydrothermal conditions using batch reactor

Supercritical water has been focused on as an environmentally attractive reaction media where organic materials can be decomposed into smaller molecules. The reaction behavior of lignin model compound was studied in near- and supercritical water with a batch type reactor. Catechol was used as a model compound for aromatic rings in lignin. The reaction was carried out at temperatures of 643-693 K at various pressures under an argon atmosphere. The chemical species in the aqueous products were identified by gas chromatography mass spectrometry (GCMS) and quantified using high performance liquid chromatography (HPLC). The effect of pressure and reaction time on the conversion process of catechol was presented. The main products from the conversion of catechol was phenol and the value of global rate constant for catechol conversion (k) is 3.0 × 10⁻⁴-11.0 × 10⁻⁴ min⁻¹.