Crystalline Products Research Articles

Experimental studies of the inhibitory effect of thiamazole on copper corrosion in near neutral 3% sodium chloride solution

As the unused drugs which are disgracefully arranged can contaminate the environment, a conceivable application of unused pharmaceutical compounds as corrosion inhibitors was successfully implemented, in this context thiamazole was assessed as a potential copper corrosion inhibitor in near neutral 3% sodium chloride solution. Electrochemical methods, surface and solution analysis are used to explore copper corrosion and its resistance. Corrosion of copper and its inhibition by thiamazole have been investigated in 3% NaCl solution using Potentiodynamic polarization, Electrochemical impedance spectroscopy, X-rays diffraction analysis, Scanning electron microscopy (SEM) along with Energy dispersive X-ray spectroscopy(EDX),contact angle measurements, Inductively Coupled Plasma (ICP) and Ion chromatography(IC).According to polarization measures, thiamazole works as a mixed type inhibitor. The values of polarization resistance and inhibition efficiency increase with thiamazole concentration increase, according to electrochemical impedance spectroscopy data. After 24 h immersion time of copper sheets in free amd containing thiamazole solution, it was revealed that thiamazole behave as mixed-type inhibitor with an efficiency of 97%. SEM/EDX investigations confirm that thiamazole forms a protective and hydrophobic layer on copper surface, this finding was assessed by contact angle (CA) tests; these results are further supported by XRD patterns that show the removal of crystalline corrosion products. The results of inductively coupled plasmasolution analysis and ionic chromatography demonstrate that in the presence of 10-4 M thiamazole in the investigated solution, the concentration of chloride increased while the concentration of copper (II) ions decreased.The outlined findings infer that the used molecule plays a role of an environmentally friendly corrosion inhibitor.

Preparation and curing method of red mud-calcium carbide slag synergistically activated fly ash-ground granulated blast furnace slag based eco-friendly geopolymer

The commercial alkali activators could account for more than 50% of the cost for producing geopolymers. Thus, to lower the carbon footprint of geopolymer by avoiding the utilization of energy-intensive commercial alkali activators, a novel eco-friendly geopolymer was synthesized from 100% solid wastes comprising red mud (RM), calcium carbide slag (CS), ground granulated blast furnace slag (GGBS) and fly ash (FA) in this study. Effects of GGBS contents and curing conditions on the compressive strength, fluidity and water requirement for normal consistency were investigated. The hydration products in the binders cured at different conditions were characterized by X-ray diffraction (XRD), thermogravimetric (TG), Fourier transformation infrared spectroscopy (FTIR) and scanning electronic microscopy (SEM). The results showed that GGBS improves the compressive strength as well as the mortar fluidity and reduces the water requirement for normal consistency of the geopolymer. Raising the curing temperature up to 60 °C and prolonging the heat curing duration to 12 h facilitate the dissolution and polymerisation of the FA-GGBS and therefore increase the amount of gel and crystalline products, whereas excessive heat-curing at temperatures higher than 60 °C and durations longer than 12 h causes shrinkage cracks at later age, which was detrimental to the compressive strength. The mineralogical characterization revealed that the amount of gel governs the strength development and heat curing favors the formation of secondary crystalline phase hydrotalcite. The developed binder can be used to produce low-carbon clinker-free concrete blocks to improve the sustainability of concrete industry.

Variation of Spin-Transition Temperature in the Iron(III) Complex Induced by Different Compositions of the Crystallization Solvent

We crystallized the Schiff-base iron(III) spin-crossover complex [Fe(3,5Cl-L5)(NCSe)] from different two-component solvent mixtures containing methanol and chloroform (Φ = V(CH3OH)/V(solvent) = 0.05, 0.25, 0.50, 0.83, and 1.00). The obtained crystalline products were characterized by X-ray diffraction, and it was confirmed that they are all composed of the same crystalline phase, and they do not contain any crystal solvent. However, significant differences in magnetic properties were observed, and thermal hysteresis changed from (in K) 121T↓ and 134T↑ for Φ = 0.05 and 0.25, down to 72T↓ and 96T↑ for Φ = 1.00. The crystal structures of the low-spin and high-spin phases were studied theoretically and experimentally.

Microporous Metal-Phosphonates with a Novel Orthogonalized Linker and Complementary Guests: Insights for Trivalent Metal Complexes from Divalent Metal Complexes.

The reliable self-assembly of microporous metal-phosphonate materials remains a longstanding challenge. This stems from, generally, more coordination modes for the functional group allowing more dense structures, and stronger bonding driving less crystalline products. Here, a novel orthogonalized aryl-phosphonate linker, 1,3,5-tris(4'-phosphono-2',6'-dimethylphenyl) benzene (H6 L3) has been used to direct formation of open frameworks. The peripheral aryl rings of H6 L3 are orthogonalized relative to the central aromatic ring giving a tri-cleft conformation of the linker in which small aromatic molecules can readily associate. When coordinated to magnesium ions, a series of porous crystalline metal-organic, and hydrogen-bonded metal-organic frameworks (MOFs, HMOFs) are formed (CALF-41 (Mg), HCALF-42 (Mg), -43 (Mg)). While most metal-organic frameworks are tailored based on choice of metal and linker, here, the network structures are highly dependent on the inclusion and structure of the guest aromatic compounds. Larger guests, and a higher stoichiometry of metal, result in increased solvation of the metal ion, resulting in networks with connectivities increasingly involving hydrogen-bonds rather than direct phosphonate coordination. Upon thermal activation and aromatic template removal, the materials exhibit surface areas ranging from 400-600 m2 /g. Self-assembly in the absence of aromatic guests yields mixtures of phases, frequently co-producing a dense 3-fold interpenetrated structure (1). Interestingly, a series of both more porous (530-900 m2 /g), and more robust solids is formed by complexing with trivalent metal ions (Al, Ga, In) with aromatic guest; however, these are only attainable as microcrystalline powders. The polyprotic nature of phosphonate linkers enables structural analogy to the divalent analogues and these are identified as CALF-41 analogues. Finally, insights to the structural transformations during metal ion desolvation in this family are gained by considering a pair of structurally related Co materials, whose hydrogen-bonded (HCALF-44 (Co)) and desolvated (CALF-44 (Co)) coordination bonded networks were fully structurally characterized.

An initial study on the effect of nano-zirconium on the behavious of alkali-activated slag cement subjected to seawater attack

In this article, for the first time, the possibility of adding nano-zirconium (NZ) into alkali-activated slag (AAS) cement as a modifier agent against seawater attack was studied. Different ratios of 1 %, 3 % and 5 % from NZ were added into the neat AAS cement. The effect of these additions on workability and compressive strength was measured. After initial curing, some specimens were exposed to seawater attack for 3, 6 and 12 M, whilst the others were cured in the air and tap water for the same periods for comparison purposes. The variation in the crystalline phases, hydration products and microstructures caused by the inclusion of different ratios of NZ were monitored by using X-ray diffraction (XRD), thermogravimetric analysis and its differential (TGA/DTG) and scanning electronic microscopy (SEM). The results showed a negative effect of NZ on workability. The incorporation of 1 % and 3 % NZ showed a positive effect on compressive strength before and after exposure to different media, whilst the incorporation of 5 % showed a negative effect. The optimum ratio of NZ was 1 %. This ratio can produce a denser and more compact microstructure, which can act as a barrier against ions and chloride diffusion from seawater to the specimens as well as migration of alkalis from the specimens to seawater.

Effect of basicity on the flow and crystallization behavior of synthetic nickel–iron alloy residue

The new technology of mineral wool production with Nickel–Iron alloy waste residue has excellent prospect of development and application. The viscosity and crystallization behavior of Nickel–Iron alloy waste residue significantly influence the production process of the mineral wool. In current work, the influences of basicity on the viscosity and crystallization for four Nickel–Iron alloy waste residues have been investigated by confocal scanning laser microscope and viscometer, respectively. The crystals morphologies are characterized by field scanning electron microscope, and the compositions are analyzed by energy dispersive spectroscopy. According to the results, it is obvious that the experimental slag crystallization behaviors are consistent with crystallization kinetic model (Johnson-Mehl-Avrami equation). The crystallization rate, the crystal size, and the crystallization ability of Nickel–Iron alloy waste residue increases with increasing the slag basicity from 0.03 to 0.53. The main crystalline product is protopyroxene for No. 1 and No. 2 slags, and olivine for No. 3 and No. 4 slags. However, the viscosity of Nickel–Iron alloy waste residue decreases with the increase of basicity. The precipitation process of crystal has great influence on the viscosity of slag, and the influence degree of different crystal types is different. When the crystals in the slag grow up to a certain extent, the viscosity of the slag will increase dramatically.

Transformation of amorphous calcium carbonate in the presence of magnesium, phosphate, and mineral surfaces

Amorphous calcium carbonate (ACC) is known as a precursor to crystalline calcium carbonate polymorphs (CaCO3) in various natural and synthetic systems. While ACC has been shown to form by heterogeneous nucleation in biological systems, it is less obvious whether it plays any role in inorganic settings where carbonate minerals grow on pre-existing surfaces. Tight assemblies of calcium carbonate (CaCO3) phases and clay minerals occur in rock-forming quantities in marlstones, are abundant in Earth’s critical zone, in the sediments of aqueous environments, and in the atmosphere as aerosol particles. Previous studies suggested that the co-occurrence of clay and carbonate minerals (especially smectite and calcite) results from the heterogeneous nucleation of CaCO3 on the surface of smectite. In order to understand the role of ACC in the heterogeneous nucleation of carbonate minerals and the effects of common silicate mineral surfaces on the stability of ACC, we synthesized ACC both in the presence and absence of smectite, kaolinite, and quartz, monitored the pH of the solution during the experiments, and studied the precipitated phases with various transmission electron microscopy techniques. Since Mg2+ and (PO43−) ions are known to prolong the lifetime of ACC and are important components in natural aqueous environments, we tested their effects on ACC transformation in both homogeneous and heterogeneous systems.In all studied systems ACC was the first condensed carbonate phase. The presence of smectite in the solution reduced the lifetime of ACC and led to the rapid formation of calcite. We suggest that the main factor driving the transition was the enhanced growth of ACC particles on the surfaces of smectite flakes. On the other hand, the presence of kaolinite and quartz slightly increased ACC stability; ACC typically rimmed the silicate particles and transformed slower than separated, individual ACC particles. When Mg2+ was present in the solution, ACC stability significantly increased and led to the formation of aragonite instead of calcite in both homogeneous and heterogeneous systems. The presence of (PO4)3− ions caused only a minor delay in ACC transformation and the crystalline product was calcite, irrespective of the presence of silicate minerals. These observations suggest that smectite minerals play important roles in the formation of carbonate minerals by providing a suitable surface for the rapid growth and coalescence of ACC particles, leading to larger particle sizes which, in turn, result in the conversion of ACC into calcite.

Self-Activation of Inorganic-Organic Hybrids Derived through Continuous Synthesis of Polyoxomolybdate and para-Phenylenediamine Enables Very High Lithium-Ion Storage Capacity.

Inorganic-organic hybrid materials with redox-active components were prepared by an aqueous precipitation reaction of ammonium heptamolybdate (AHM) with para-phenylenediamine (PPD). A scalable and low-energy continuous wet chemical synthesis process, known as the microjet process, was used to prepare particles with large surface area in the submicrometer range with high purity and reproducibility on a large scale. Two different crystalline hybrid products were formed depending on the ratio of molybdate to organic ligand and pH. A ratio of para-phenylenediamine to ammonium heptamolybdate from 1 : 1 to 5 : 1 resulted in the compound [C6 H10 N2 ]2 [Mo8 O26 ] ⋅ 6 H2 O, while higher PPD ratios from 9 : 1 to 30 : 1 yielded a composition of [C6 H9 N2 ]4 [NH4 ]2 [Mo7 O24 ] ⋅ 3 H2 O. The electrochemical behavior of the two products was tested in a battery cell environment. Only the second of the two hybrid materials showed an exceptionally high capacity of 1084 mAh g-1 at 100 mA g-1 after 150 cycles. The maximum capacity was reached after an induction phase, which can be explained by a combination of a conversion reaction with lithium to Li2 MoO4 and an additional in situ polymerization of PPD. The final hybrid material is a promising material for lithium-ion battery (LIB) applications.

Investigation of water stability and microcharacteristics of magnesium potassium phosphate cement modified by calcium aluminate cement and wollastonite

The early water stability of magnesium potassium phosphate cement (MKPC) blended with calcium aluminate cement (CAC) and wollastonite (WS) was investigated. Macroscopically, the presence of CAC prolongs the setting time of MKPC becauseof the stimulating effect of the admixture on the composite retarder. The synergistic effect between CAC and WS enhances the early water stability and compressive strength of MKPC subjected to water curing. From the microscopic aspect, the X-ray diffraction and Fourier transform infrared spectroscopy results indicate that the CAC phase participates in the reaction of the MKPC system to produce crystalline (metavariscite) and amorphous (hydroxyapatite and gibbsite) products. In contrast, although WS does not participate in the reaction, it inhibits the development of cracks and strengthens the brittle matrix. Furthermore, the results of the scanning electronic microscopy–energy dispersive spectrometry, mercury intrusion porosimetry, and Brunauer-Emmett-Teller nitrogen adsorption–desorption analysis confirm that the amorphous products coating the surface of struvite-K can change its solubility. Meanwhile, the crystalline product is embedded in the gap of struvite-K crystals, refining the pore structure and preventing water from entering the interior of the hardened paste.

Proportioning, Carbonation, Performance Assessment, and Application of Reactive Magnesium Oxide Cement–Based Composites with Superplasticizers

Formulation of highly workable reactive magnesium oxide (MgO) cement (RMC)–based composites is critical to their wider adoption in the construction industry. Yet, the performance of the binder with the presence of chemical admixtures is not well understood. This study assessed the influence of polycarboxylate ether (PCE)–based superplasticizers on the hydration and carbonation kinetics of RMC. Its application was also demonstrated. RMC-based composites were prepared with conventional aggregates, superplasticizers to aid workability, and fibers to control cracking induced by volume changes under both hydration and carbonation. Two carbonation methods were utilized: 20% CO2 in a carbonation chamber and CO2 in an enclosed plastic bag to emulate a low-technology carbonation process. Highly workable RMC-based mortar mixes were achieved with a superplasticizer content of 2% by weight, despite the presence of 0.2% by volume polyethylene microfibers. The admixtures slowed down the hydration rate and altered the morphology of the hydration product. Compressive strength of 32.7 MPa was attained after 7 days under 20% CO2 in a carbonation chamber compared with 15.6 MPa under carbonation inside the plastic bag condition. The crystalline carbonation products within the exterior regions were dominated by nesquehonite. A significantly reduced carbonation level was observed within the interior regions due to the formation of the carbonation products and the resulting pore refinement within the exterior regions. Also, the PE fibers provided a crack control mechanism, and their failure mode was characterized by pullout. The finalized mix was successfully applied for the construction of a large-scale architectural structure.

Hands-on X-ray Crystallography: A Research-Based Elective Program for Secondary School Students

This article describes a program that was developed to introduce senior high school students in Melbourne, Australia to the technique of X-ray crystallography within the context of chemistry research. Students had an opportunity for original experimentation, performing reactions and attempting to grow crystals of reaction products in a school laboratory. The program was remarkably successful, based on student feedback and scientific outcomes. In most cases, the compounds generated by students had not been synthesized before and their structures were previously unknown. X-ray diffraction data were collected on these crystalline products, and the students participated in data analysis and structure determination. New crystal structures were submitted to the international Cambridge Structural Database, with appropriate recognition of the students involved. Two peer-reviewed reports have been accepted for publication in the research literature with the students listed as coauthors. The experiences of the authors in developing this program should be of particular interest to science educators designing outreach activities for high school students.

Role of Al and Mg alloying elements on corrosion behavior of zinc alloy‐coated steel substrates in 0.1 M NaCl solution

AbstractThe corrosion behavior and corrosion products of three zinc alloy‐coated steel substrates with different Al and Mg contents such as hot‐dip galvanized steel (HDG), Zn–Al‐coated steel (ZA), and Zn–Al–Mg‐coated steel (ZM) substrates were investigated during 168 h of immersion in 0.1 M NaCl solution. The characteristics and morphology of corrosion products on all the substrates formed during exposure to electrolyte solution were observed by X‐ray diffraction, X‐ray photoelectron spectroscopy, and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy. Their electrochemical behavior was investigated by open‐circuit potential, polarization curves, and electrochemical impedance spectroscopy. The addition of Al and Mg alloying elements affected the corrosion mechanism as well as the anticorrosion properties. The main crystalline corrosion products on the HDG surface were simonkolleite and zincite, while the ZnAl hydrotalcite was identified as the main corrosion product on ZA and ZM surfaces. The corrosion resistance of ZA and ZM substrates was improved compared to the HDG substrate due to the enhanced adhesion of the corrosion product layer.

Influences of crystallization time, batch molar ratios Al2O3/SiO2 and Na2O/SiO2 on particulate properties of sodalite crystals prepared under room-temperature conditions

Sodalite crystals were prepared by the hydrothermal method under room-temperature conditions. The influences of crystallization time, batch molar ratios Al2O3/SiO2 and Na2O/SiO2 on the crystalline end products were investigated. For comparison, an experiment was also carried out in which sodalite was synthesized at 90 °C for 10 h. The results revealed that with the prolongation of crystallization time from 1 h to 14 days, the crystallization followed a sequence of phase transformations from an amorphous phase to zeolite NaA, and finally to sodalite. Spherical sodalite crystals composed of very small crystallites were obtained after 10 h of room-temperature crystallization. Whereas, with the same gel composition, the sodalite synthesized at 90 °C for 10 h was large lepispherical particles. High Al2O3/SiO2 molar ratio favored the generation of smaller individual sodalite nanocrystals, which resulted in the formation of larger steady congregated agglomerates. Moreover, alkalinity circumstance determined whether or not sodalite was formed. Well-developed cubic zeolite NaA particles were obtained at Na2O/SiO2 = 1.4; when the Na2O/SiO2 was increased to 8.0, zeolite NaZ-21 crystals were generated, meanwhile, the decomposition of wool ball-like sodalite particles into nanorods was also observed.

Carbon-Carbon Linked Organic Frameworks: An Explicit Summary and Analysis.

Organic frameworks with carbon-carbon (CC) linkage are an important class of materials owing to their outstanding chemical stability and extended π-electron delocalization resulting in unique optoelectronic properties. In the first part of this review article, the design principles for the bottom-up synthesis of 2D and 3D sp/sp2 CC linked organic frameworks are summarized. Representative reaction methodologies, such as Knoevenagel condensation, Aldol condensation, Horner-Wadsworth-Emmons reaction, Wittig reaction, and coupling reactions (Ullmann, Suzuki, Heck, Yamamoto, etc.) are included. This is discussed in the context of their reaction mechanism, reaction dynamics, and whether and why resulting in an amorphous or crystalline product. This is followed by a discussion of different state-of-the art bottom-up synthesis methodologies, like solvothermal, interfacial, and solid-state synthesis. In the second part, the structure-property relationships in CC linked organic frameworks with representative examples of organocatalysis, photo(electro)catalysis, energy storage and conversion, magnetism, and molecular storage and separation are analyzed. The importance of linkage type, building blocks, topology, and crystallinity of the framework material in connection with the structure-property relationship is highlighted. Finally, brief concluding remarks are presented based on the key development of bottom-up synthetic methods and provide perspectives for future development in this field.

Synthesis of lanthanum(III)-containing heteropoly compounds with a Peacock-Weakley type anion from aqueous-organic solutions

Conditions necessary for the formation of La(III)-containing polyoxotungstates in solutions of the system Na2WO4 – HNO3 – La(NO3)3 – H2O/Solvent (Solvent = acetone, acetonitrile, ethanol; 50/50 vol.% Н2О: Solvent ratio) acidified to acidity Z = ν(H+)/ν(WO42–) = 0.80 were elaborated. It was established that during salting out, the addition of an organic solvent leads to the crystallization of normal salts, Na9[La(W5O18)2]·nH2O (n = 32–35). Using FT-IR spectroscopy, it was shown that the anion [La(W5O18)2]9– in the composition of the isolated salts belongs to the Peacock–Weakley type of structure and the absence of solvent molecules in the composition of the crystalline product was established. Using the method of scanning electron microscopy, the single-phase nature of the synthesized salts was established (according to the uniform contrast of the surface of the samples during scanning in the backscattered electron mode and according to the results of energy dispersive X-ray microanalysis), and the grain sizes were determined (from 140–300 nm for the salt isolated from the H2O: acetone medium, to 300–450 nm for the salt isolated from the H2O: ethanol system). Microphotographs of powders of Na9[La(W5O18)2]·nH2O salts powders in characteristic X-ray emission do not show zones with different surface morphology, and demonstrate uniform distributions of Na, La, W, and O without segregation, which confirms the single–phase nature of the samples isolated from aqueous-organic solutions. The conducted research made it possible to expand the list of organic solvents that can be used for the synthesis of normal salts with a heteropoly anion with a Peacock–Weakley type of structure from aqueous-organic solutions. The use of acetonitrile and ethanol for Na9[La(W5O18)2 ]·nH2O isolating can be extended to the synthesis of salts with other lanthanide heteroatoms.

Influence of Rapid Heat Treatment on the Photocatalytic Activity and Stability of Strontium Titanates against a Broad Range of Pollutants

Strontium titanate (STO) photocatalysts were prepared via a slightly modified Pechini sol–gel method. A unique rapid calcination technique with a short exposure time was used to obtain crystalline products. The samples were characterized by X-ray diffractometry, scanning electron microscopy, diffuse reflectance spectroscopy, infrared spectroscopy, nitrogen adsorption–desorption measurements, and X-ray photoelectron spectroscopy. Their photocatalytic activity was evaluated by the photocatalytic oxidation of phenol, oxalic acid, and chlorophenol under UV light irradiation using commercial STO as a reference. These pollutants, together with glucose and propanol, were used to investigate the stability of the samples against various functional groups. All our samples exhibited higher photocatalytic activity than the commercial STO reference. With increasing calcination temperature, the crystallinity and primary crystallite sizes increased while the band gaps and specific surface areas decreased. The photocatalytic activity of the most efficient sample was explained by the presence of SrCO3 on its surface. The STO catalysts were highly stable as they largely retained their crystalline composition after exposure to chemicals with different functional groups. Finally, we compared the costs associated with the unique calcination technique with a more conventional one and found that our method is ~35% more cost-effective.

Utilization of gasification slag and petrochemical incineration fly ash for glass ceramic production.

This study investigated glass ceramics produced using coal gasification slag (CGS) and petrochemical incineration fly ash (PIFA) to immobilize hazardous heavy metals such as Cr and As. However, the crystallization kinetics and stabilization behavior mechanism of different heavy metals in the petrochemical incineration fly ash-derived glass-ceramics remains unclear. And X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and inductively coupled plasma mass spectrometry were used to characterize glass and crystalline products. In this paper, we reported the crystallization kinetics and chemical leaching characteristics of the glass ceramic. A low crystallization activation energy of 121.49kJ/mol was achieved from crystallization peak of several different heating rates around 850°C, implying that it is easier to produce the glass ceramics at that temperature. The Avrami parameter of the former crystallization was determined to be 1.23 ± .12, which indicated two-dimensional crystal growth with heterogeneous nucleation. The toxicity characteristic leaching procedure results indicated that the heavy metals were well solidified, and that the leaching concentration was significantly lower than the limit specified by governmental agencies. The potentially toxic element index of the parent glass and the two glass ceramics were 11.7, 5.8, and 3.6, respectively. Therefore, the conversion of hazardous petrochemical incineration fly ash and other solid waste into environmentally friendly glass ceramics shows considerable potential and reliability.

Binary to ternary drug-drug molecular adducts of the antihypertensive drug ketanserin (KTS) with advanced physicochemical properties.

Focusing on a reliable supramolecular synthon approach, novel molecular salts of the antihypertensive medication ketanserin (KTS) with aromatic carboxylic acid derivatives (benzoic acid (BA), 2-hydroxybenzoic acid (2-HBA), and 2,5-dihydroxybenzoic acid (2,5-DHBA)) are reported. Binary salts of KTS with the respective salt former were obtained via solvent-assisted grinding followed by solution crystallization. Salt production was confirmed through crystal structure investigations that revealed proton transfer from the carboxylic acid group of the salt former to the piperidine nitrogen atom of KTS. A rigorous investigation of the crystal packing of novel binary salts of KTS inspired the construction of ternary adducts, and a ternary crystalline product was subsequently identified using milrinone (MLN), another cardiotonic drug. According to our knowledge, this is the first instance of a dual-drug ternary co-crystal combining both antihypertensive drugs. In order to evaluate the impacts of co-crystallization on the in vitro release behaviour of binary and ternary adducts, solubility tests for the cocrystal were carried out under a variety of physiological pH conditions. The results indicate that, in contrast to the parent drug and binary adducts, the solubility rate of the ternary adducts is significantly increased. Finally, the stability of the synthesised adduct was evaluated under a range of conditions, including temperature (40 ± 1 °C), humidity (90% ± 5% RH, 25 °C) and various solvents media, and it was established that they have good stability. We anticipate that the present findings will work with a wide range of medication combinations, providing a potential new approach to create multi-drug systems for cardiovascular disease.

Obtaining of 24-Norchol-4-ene-3,22-dione from Phytosterol with Mutants of Mycolicibacterium neoaurum.

Engineered mutants of Mycolicibacterium spp. are known producers of valuable steroid synthons with C19 or C22 skeleton. Here we describe a method for site-directed mutagenesis of Mycolicibacterium neoaurum strains, bioconversion from phytosterol, and selective purification of C23 steroid 24-norchol-4-ene-3,22-dione (24-NCED) and C22 steroid 20-hydroxymethylpregn-4-ene-3-one (20-HMP). The yields of crystalline products with 95% purity by the method here described are 2.74±0.085g for 24-NCED and 1.42±0.085g for 20-HMP from 10g/L phytosterol. 20-HMP is recognized as the key precursor in chemical syntheses of pharmaceutical corticosteroids and 24-NCED is a promising synthon for the synthesis of valuable steroids and own potent biological activity.

Quantitative study on the dielectric properties of tricalcium silicate pastes under different W/C

C3S (tricalcium silicate) pastes with water-cement ratio (W/C) of 0.23, 0.3, 0.4 and 0.5 were designed, and the influence of the dielectric properties of C3S paste were quantitatively analyzed. The results show that when the W/C is 0.23, the real part of permitivity of the C3S paste is the smallest. With increases of the W/C, the real part of permitivity of the C3S paste decrease, and the loss tangent increases. The real part of permitivity of C3S paste decreases with the increase of Ca(OH)2 and pore phases, and increases with the increase of C3S and CSH gel phase. The permitivity of C3S paste decreases most due to increase pore phase (about 4 times that of Ca(OH)2 phase), and increases most due to increase CSH gel phase (about 6.6 times that of C3S phase). The dielectric weight coefficient proposed in this study can well predict the changing trend of the real part of permitivity of C3S pastes with different W/C. Finally, based on the Thermogravimetric analysis (TGA), Scanning electron microscope (SEM), Mercury intrusion porosimetry (MIP), N2 adsorption and 29Si magic angle spinning nuclear magnetic resonance (29Si NMR) test results, the reasons of electromagnetic loss changes of C3S pastes with different W/C were analyzed from the molecular structure of CSH gel, the crystalline products and the pore structure of C3S paste.