Easy Dehydration Research Articles

Water-assisted preparation of Ni/La(OH)3 catalyst for efficient catalytic C-O bond hydrogenolysis of tetrahydrofuran-dimethanol

Due to easy dehydration of La(OH)3 to LaOOH by thermal treatment, it is challenging to prepare highly efficient Ni/La(OH)3 catalyst for hydrogenolysis reactions. Herein, Ni/La(OH)3 (Ni/La-2) catalyst is prepared by thermal reduction of NiO/La(OH)3 in hydrogen flow with vaporized water, while La(OH)3 is partially dehydrated to LaOOH without water vapor affording Ni/(La(OH)3 + LaOOH) (Ni/La-1). Ni/La-2 displays 93 % and 3 % yields of 1,2,6-hexanetriol (HTO) and 1,6-hexanediol (HDO) respectively towards C-O hydrogenolysis of tetrahydrofuran-dimethanol (THFDM) in batch reactor and high stability (200 h) in fixed-bed reactor, which is the best among the reported catalysts to the best of our knowledge. Ni/La-2 possesses pure La(OH)3 as support, enhanced dispersion of Ni species and abundant Niδ+-O-La interfaces in comparison to Ni/La-1, which results in the exceptional catalytic performances in C-O hydrogenolysis of THFDM. A fine control of reaction temperature and time is required to optimize the yields HTO and HDO in hydrogenolysis of THFDM over Ni/La-2. The water-assisted preparation method provides a new perspective for the preparation of La(OH)3 supported metal catalysts.

Preparation and Experimental Research of Temperature Sensitive Expansion Gel Material for Fire Prevention and Extinguishing in Coal Mines

ABSTRACT In order to solve the problems of high viscosity at room temperature, easy dehydration and shrinkage of phase change gel, and poor plugging effect of traditional mine gel, a new type of temperature-sensitive expansion gel was developed by using hydroxypropyl methyl cellulose, chitosan, guar gum and sodium bicarbonate as raw materials, using orthogonal test and response surface analysis. The structural characterization, characteristics, fire prevention, and extinguishing performance of the temperature-sensitive expansion gel were tested. The experimental results show that the optimal ratio of temperature-sensitive swelling gel is 0.75 wt % chitosan, 0.5 wt % acetic acid, 2.5 wt % hydroxypropyl methyl cellulose, 0.4 wt % sodium bicarbonate, and 0.15 wt % guar gum. The phase transition temperature (LCST) of this ratio is 67°C. After standing at room temperature for 6 h, the gel viscosity is 5852 mpa·s, the expansion ratio is 0.846, and the strength is 319.525 N/m2. During the heating process of the coal sample after adding the temperature-sensitive expansion gel, the gel will undergo phase change and expansion in the high-temperature area of the coal, and the viscosity will increase. It can stay in the high-temperature area, wrap the coal block, and isolate the oxygen from entering, thus effectively inhibiting the coal spontaneous combustion process. In addition, the gel also produces inert gas carbon dioxide, which effectively suffocates the flame. Therefore, compared with the conventional inhibitor solution, the temperature-sensitive expansion gel has better fire extinguishing effect.

Conductive Hyaluronic Acid/Deep Eutectic Solvent Composite Hydrogel as a Wound Dressing for Promoting Skin Burn Healing Under Electrical Stimulation.

Burns can cause severe damage to the skin due to bacterial infection and severe inflammation. Although conductive hydrogels as electroactive burn-wound dressings achieve remarkable effects on accelerating wound healing, issues such as imbalance between their high conductivity and mechanical properties, easy dehydration, and low transparency must be addressed. Herein, a double-network conductive eutectogel is fabricated by integrating polymerizable deep eutectic solvents (PDESs)including acrylamide/choline chloride/glycerol (acrylamide-polymerization crosslink) and thiolated hyaluronic acid (disulfide-bonding crosslink). The introduction of PDESs provides the eutectogel with a conductivity (up to 0.25 S·m-1) and mechanical strength (tensile strain of 59-77%) simulating those of natural human skin, as well as satisfactory tissue adhesiveness, self-healing ability, and antibacterial properties. When combined with exogenous electrical stimulation, the conductive eutectogel exhibits the ability to reduce inflammation, stimulate cell proliferation and migration, promote collagen deposition and angiogenesis, and facilitate skin tissue remodeling. This conductive eutectogel shows great potential as a dressing for healing major burn wounds.

Research Progress on Attached Culture Technology of Microalgae

In order to solve the problem of microalgae biomass harvesting in suspension systems, attached culture systems were proposed. In this system, microalgae are fixed on the surface or inner layer of the carrier and grow in an aggregated form. Compared with suspension culture, attached culture has higher microalgae biomass density and easier dehydration and harvesting processes. The biomass can be harvested by simply separating the carrier containing microalgae from the culture medium.

A high-strength, environmentally stable, self-healable, and recyclable starch/PVA organohydrogel for strain sensor

Conductive hydrogels have attracted great interest in the fabrication of flexible strain sensors. However, hydrogel-based strain sensors still have unresolved challenges, such as low mechanical strength, lack of frost resistance, easy dehydration, and non-recyclability, which have largely hindered their application. Herein, the ion-conductive starch/PVA/EG/TA/CaCl2 (SPETC) composite organohydrogel was prepared by the cyclic freezing-thawing method using starch and PVA as the gel backbone, water and ethylene glycol (EG) as the binary solvent, and Ca2+ and Cl- as the conducting ions carriers. The SPETC organohydrogel exhibited high mechanical properties and showed excellent environmental stability and frost resistance. SPETC organohydrogel was fully physically cross-linked by non-covalent interactions such as hydrogen bonding and ligand bonding, and these reversible interactions can give the gel good recyclability. Moreover, benefiting from the superior mechanical response, SPETC organohydrogel can be assembled as a flexible wearable strain sensor for real-life motion monitoring.

Route Optimization of Agricultural Product Distribution Based on Agricultural Iot and Neural Network from the Perspective of Fabric Blockchain

With the fast growth of AI and Internet of Things (IoT) technology, many agricultural product sales businesses and logistics sectors have started to concentrate on agricultural product distribution information operations. The requirements for the delivery service time are very high due to the features of perishable and highly easy dehydration of fresh agricultural goods. To preserve the freshness and quality of agricultural goods, the logistics and distribution process must be completed as rapidly as possible via appropriate low temperature control and the use of IoT technology. IoT technology will surely bring about the intelligent operation in the circulation of agricultural products. With the decentralized management of the Fabric blockchain, the investment and maintenance costs of the agricultural IoT will be reduced, which will help to improve the intelligence and scale of the agricultural IoT. Aiming at the specific problems, the path optimization problem in the process of agricultural product distribution is brought out. This paper completes the following work: (1) the traditional agricultural product distribution process is roughly described, and the shortcomings and problems of the traditional mode are explored and studied. On this basis, the agricultural product circulation mode under the IoT and neural network technology is introduced. (2) The TSP problem is defined, then some algorithms commonly used to solve the TSP problem are introduced, and then the theory and method of the SOM neural network and the basic principle of the ORC_SOM algorithm are introduced in detail. (3) Through a large number of experiments, the results prove the validity of the algorithm in this paper and the rationality of the theory.

Characterization of Hemp (Cannabis sativa L.) Biodiesel Blends with Euro Diesel, Butanol and Diethyl Ether Using FT-IR, UV–Vis, TGA and DSC Techniques

Blending biodiesel–diesel blends with alternative fuels such as butanol and diethyl ether becomes an interesting area of research. Butanol is becoming a popular fuel due to its renewable nature and superior properties compared to ethanol. Diethyl ether can be considered as a renewable fuel as it can be produced from bioethanol through easy dehydration process. This paper aims to study the physicochemical properties of biodiesel produced from Hemp (Cannabis sativa L.) and its blends with Euro diesel, butanol and diethyl ether. Furthermore, characterizations such as DSC, FT-IR, UV–Vis and TGA were also analyzed. Most of the properties of biodiesel satisfy EN 14214 and ASTM D6751 standards except iodine value and oxidation stability due to the high degree of unsaturation (128.549). Blending of hemp biodiesel with Euro diesel, butanol and diethyl ether improved the cold flow properties, kinematic viscosity and density. However, flash point decreased dramatically specially when blending with diethyl ether due to its low flash point. Therefore, care should be taken when handling or transporting biodiesel–diesel–diethyl ether blends. This work supports that blending Hemp methyl ester with Euro diesel, butanol and diethyl ether as ternary blends (up to 20%) can be considered as alternatives to fossil diesel in CI diesel engines. Therefore, it is recommended that engine, emissions and combustion characteristics of all blends shall be further investigated.

Formulation Development of High Strength Gel System and Evaluation on Profile Control Performance for High Salinity and Low Permeability Fractured Reservoir.

For the large pores and cracks of reservoirs with low temperatures, high salinity, and low permeability, a new type of high strength gel ABP system is developed in this paper. The defects of conventional gels such as weak gel strength, no gelling, and easy dehydration are overcome under the conditions of low temperature and high salinity. The temperature and salt resistance, plugging characteristics, and EOR of the gel system are studied. Under the condition of 32°C and 29500 mg/L salinity, the ABP system formulation is for 0.3% crosslinking agent A + 0.09% coagulant B + 3500 mg/L polymer solution P. The results show that when the temperature was increased, the delayed crosslinking time of the system was shortened and the gel strength was increased. The good plugging characteristics of the ABP system were reached, and the plugging rate was greater than 99% in cores with different permeability. A good profile control performance was achieved, and the recovery rate was improved by 19.27% on the basis of water flooding. In the practical application of the gel system, the salinity of formation water and the permeability of fractures are necessary to determine the appropriate formulation.

The effects of monovalent metal ions on the conformation of human telomere DNA using analytical ultracentrifugation.

A human telomere DNA segment (HT-DNA) can fold into a G-quadruplex in the presence of some monovalent cations. These cations can interact with the phosphate groups of the DNA segment and/or with the O6 oxygen atom of guanines, which are called non-specific interactions and specific interactions, respectively. However, until now how these two interactions affect the structure of HT-DNA has not been well understood. In this study, a combination of analytical ultracentrifugation (AUC) and circular dichroism (CD) was used to explore the effects of these two interactions on the structure of a 22-mer single-stranded DNA with a sequence of 5'-AGGG(TTAGGG)3-3'. The results showed that the standard sedimentation coefficient (s20,w) of HT-DNA starts to increase when the concentration of potassium ions (CK(+)) is higher than 10.0 µM due to the formation of a G-quadruplex through specific interactions. Whereas, for a control DNA, a higher CK(+) value of 1.0 mM was needed for increasing s20,w due to non-specific interactions. Moreover, potassium ions could promote the formation of the G-quadruplex much more easily than lithium, sodium and cesium ions, presumably due to its appropriate size in the dehydrated state and easier dehydration. The molar mass of DNA at different cation concentrations was nearly a constant and close to the theoretical value of the molar mass of monomeric HT-DNA, indicating that what we observed is the structural change of individual DNA chains.

Využití odpadních materiálů v pěstebních substrátech

Gardeners' practical experience and experimental work prove the affirmation that the used substrate is a very important base for the production of quality nursery products. It is important to emphasis the complexity and synergy of all factors influencing the ecosystem and there mutual relations. Physical, chemical and biological properties do not separately affect the growth and development of plants. In addition, the relations are not statical but differ in relation with other factors changes. This article is dealing with the possibility to use waste material from timber processing in cultivation substrates. The large scale use of such substrates would enable people to reach a relative independence from peat substrates, of which the global reserve is gradually decreasing.Our research activities focus on the use of bark. The basic problems of a bark substrate are easy dehydration and unbalanced nutrition of trees and shrubs. The suggested and experimented cultivation technology solves these problems. It is based on the cultivation of woody species in bark substrates, using modern irrigation systems, slow release fertilisers (Silvamix Forte) and special soil conditioners (TerraCottem). This technology was tested on the following species of trees and shrubs:MalusandBuxus.

Diels-alder polymerization of a macrocyclic metal complex with p-benzoquinone

The (hemiporphyrazinato)nickel complexes 1, 2 exhibiting isobenzofuran moieties as diene functionalities are generated in the presence of p-benzoquinone. In case of an excess of p-benzoquinone, the occuiring DA reactions afford the model compounds 3, 4, while polymerization takes place if 1 is generated in the presence of an equimolar amount of p-benzoquinone. The introduction of the carbonyl groups between the two epoxy rings leads to structure fragments which undergo easy dehydration.

Synthesis and structure of catena-poly-[μ-dichloro-(1,2,3,-η)-2-methyl-propenylrhodium

The reaction of RhCl 3 · 3H 2O with tert-butanol at 70 °C gives catena-poly-[μ-dichloro-2-methy-(1,2,3-η)-propenylrhodium], [Rh(2-CH 3(η 3-C 3H 4)]Cl 2] n (2) in high yield. The ESCA and IR spectra and the reaction of 2 with CO indicate for this compound a polymeric structure with two chlorine bridges. A reaction mechanism based on the easy dehydration of tert-butanol and on the high stability of the 2-methylallyl radical is proposed.

The crystal chemistry of copper(II) dipicolinates

The molecular structure of a new copper dipicolinate, Cu(dipic)(H 2dipic)·H 2O, and a refinement of the previously reported Cu(dipic)(H 2dipic)·3H 2O are presented. The Jahn-Teller effect, as operative in six-coordinated Cu II surrounded by two planar tridentate ligands, is responsible for the presence of a dianion and a neutral acid molecule in the structure. As opposed to previously reported copper dipicolinates, water molecules do not coordinate and in the trihydrate dehydration is facile because interstital water finds easy dehydration pathways; the mechanism involves nucleation and fast bidimensional growth. The monohydrate, however, presents tightly bound (through hydrogen bonds) water and no easy dehydration pathways are available; the dehydration mechanism involves fluid-flux nucleation, mediated by fusion. Five different copper(II) dipicolinates are known; because of the strong tendency of this ligand to form tridentate mononuclear complexes, all of them, except monoclinic Cu(dipic)·2H 2O, belong to the class of molecular solids. In the monoclinic dihydrate, carbonyl O atoms are involved in defining chains that run parallel to [001] planes.

Structure Elucidation of Furostanol Glycosides Using Liquid Secondary Ion Mass Spectrometry

The structures of five genuine furostanol glycosides isolated from Metanarthecium luteo-viride MAXIM. (Liliaceae) were determined on the basis of liquid secondary ion mass spectrometric (LSIMS) analysis including liquid secondary ion mass spectrometry/mass spectrometry (LSIMS/MS). These glycosides were elucidated as bisdesmosides of furostanols (i.e. 2-0-acetyl-furometagenin, furometagenin, furonogiragenin, 2-0-acetyl- furometanarthogenin and 2-O-acetyl-3-oxo-furometagenin) as aglycons. which have cyclic hemiacetal moieties. bearing 2,3,4-tri-O-acetyl arabinopyranose at 11−C 1) and glucopyranose at 26-C. In the LSIMS of these compounds, the protonated molecular ion [M + H] + was not observed but the fragment ion [M - OH] + corresponding to the loss of the hydroxyl group at 22-C was observed. By addition of NaCI to the sample matrix, the ion peaks for [M + Na] + appeared in the spectra, which were used to determine the molecular formulae. Molecular orbital calculation of a model compound indicated that the ions [M+Na] + were stabilized by formation of a four-membered ring structure bonding two oxygen atoms at the hemiacetal moiety and a sodium ion. Since the energy required for sodium ion addition to the neutral molecule was less than for proton addition, the sodium ion addition is more favorable. In addition, the repulsion energy of the protonated hemiacetal hydroxyl group is only 4.25 kcal/mol, and the potential energy of the fragmentation products ([M - OH] + + H 2 0) is 18.13 kcal/mol less than that of [M + H] +. These data rationalized the easy dehydration from the protonated furostanol glycoside.

ChemInform Abstract: Amino Groups Immobilized on Silica Gel: An Efficient and Reusable Heterogeneous Catalyst for the Knoevenagel Condensation.

Silica gel functionalized with amino groups is a useful insoluble catalyst for the Knoevenagel condensation: the reaction can be carried out under continuous-flow conditions and good yields are obtained when aromatic aldehydes, cyclohexanone, and acetophenone react with ethyl acetoacetate, ethyl cyanoacetate, and malononitrile. Lower yields are obtained in the case of ethyl benzoylacetate and acetylacetone; this fact and the easy dehydration of the aldol intermediate strongly suggest the participation of the residual free silanol groups of the matrix in the catalysis mechanism.

Amino groups immobilized on silica gel: an efficient and reusable heterogeneous catalyst for the Knoevenagel condensation

Silica gel functionalized with amino groups is a useful insoluble catalyst for the Knoevenagel condensation: the reaction can be carried out under continuous-flow conditions and good yields are obtained when aromatic aldehydes, cyclohexanone, and acetophenone react with ethyl acetoacetate, ethyl cyanoacetate, and malononitrile. Lower yields are obtained in the case of ethyl benzoylacetate and acetylacetone; this fact and the easy dehydration of the aldol intermediate strongly suggest the participation of the residual free silanol groups of the matrix in the catalysis mechanism.

Formation of the -lactone of 3,5-dihydroxydecanoic acid by the fungus Cephalosporium recifei.

The fungus Cephalosporium recifei NRRL 5161 produces the δ-lacetone of 3,5-dihydroxydecanoic acid, the structure of which was established by its mass spectrum and its easy dehydration to the lactone of 5-hydroxy-2-decenoic acid.

On steroidal sapogenins. IX. Some derivatives of metagenin related to steroidal hormones.

Since metagenin (Ia) and nogiragenin (IIa) have inherently 11α-hydroxyl group, both of them seemed to be the most convenient starting materials for the synthesis of cortical hormone intermediates. Several kinds of intermediates were prepared and during the course of syntheses of them, an easy dehydration of the 11α-hydroxyl grouo was found.