Study of Compositions for Selective Water Isolation in Gas Wells

A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottomhole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water. During injection, this composition shows selectivity and mostly penetrates water-saturated porous media. The study shows that the injection of such composition into porous media has a high water-insulating effect, reducing the water permeability of water-saturated porous media by 35 times with a degree of water isolation of 97%. Moreover, while injecting, it has selective action, mainly penetrating water-saturated media rather than gas-saturated media. As a result of injecting 0.91 to 0.99 pore volumes (pv) of the composition, the Qwater/Qgas ratio reaches 5.22 to 5.26, indicating high selectivity.

Same useful fixative from resin in Vietnam

Today, fixatives from natural raw materials are gradually replacing fixatives synthesized from chemicals. The arm of this research is the study of same useful resin in Vietnam for fixative substance in blending fragrance. We obtained Benzoin resin from Styrax tonkenensis Pierre plant in Ha Giang province, Canarium resin from Canarium Album L. in Dak Nong district, Dak Lak province, and Agarwood pulp of Aquilaria crassna plant in Binh Thuan province Vietnam. The material used in the experiment for the natural fragrance was taken from the project of Vietnam essential oils and related natural products. The method of this process is resin extraction by volatile solvents. The resin is dissolved in alcohol 96% and the distilled alcohol is removed to obtain absolute. The method of assessment of product quality in this study is using the olfactory to assess the odour of samples over time. Benzoin resin, Canarium resin, and Agarwood resin of Vietnam are useful fixatives in blending fragrance. The fixative ability of Benzoin resin absolute is not equal to the ability of Agarwood resin absolute but better than the ability of Canarium resin absolute. Through research and experiment, we can see Benzoin resin, Canarium resin and Agarwood resin are precious. They can be used as a good fixative in aromatherapy. This is a natural resin, a kind of resource available in Vietnam. Therefore, it is recommended for further research, exploitation, and effective use of this resource.

Ionic Liquids—A Review of Their Toxicity to Living Organisms

Ionic liquids (ILs) were initially hailed as a green alternative to traditional solvents because of their almost non-existent vapor pressure as ecological replacement of most common volatile solvents in industrial processes for their damaging effects on the environment. It is common knowledge that they are not as green as desired, and more thought must be put into the biological consequences of their industrial use. Still, compared to the amount of research studying their physicochemical properties and potential applications in different areas, there is a scarcity of scientific papers regarding how these substances interact with different organisms. The intent of this review was to compile the information published in this area since 2015 to allow the reader to better understand how, for example, bacteria, plants, fish, etc., react to the presence of this family of liquids. In general, lipophilicity is one of the main drivers of toxicity and thus the type of cation. The anion tends to play a minor (but not negligible) role, but more research is needed since, owing to the very nature of ILs, except for the most common ones (imidazolium and ammonium-based), many of them are subject to only one or two articles.

Using the Natural Fixative from Canarium Resin of Vietnam

Aim and Objectives: Nowadays, the fixative substance from natural materials is gradually replacing the fixative substance that has been synthesized from chemicals. The purpose of the study in this research is that we created a natural fragrance from Vietnamese raw material with a fixative from Canarium Album (Lour) as a natural fixative to replace artificial fixative. Canarium plant is scientifically known as Canarium Album (Lour) Raensch of the Burseraceae family. Canarium Album L. is distributed in most of Northern provinces, central Highlands, and Southeast of Vietnam. Materials and Methods: The method of this process is resin extraction by volatile solvents. We use a knife to cut into the trunk and let the resin run out, then harvest this resin to make fixative. The resin is dissolved in alcohol 96% and the distilled alcohol is removed to obtain absolute Canarium. Evaluation method of the ability of absolute Canarium is performed by comparing it with other fixatives in fragrances. Raw canarium resins is taken directly from canarium plants then refined absolute canarium as the natural fixative. We use this fixative substance in combinations of floral, woody smells and comparison with traditional artificial fixative as Musk ketone, Musk xylene, Musk ambrette. Results: The comparison results show that the ability to keep the fragrance of scent is lower than musk ambrette, musk ketone but it is better than musk xylene. Thus, canarium resin can be used as a natural fixative to replace artificial fixative in fragrance. Conclusions: Through research and experiment, we can see Canarium resin is precious. It can be used as a good fixative in aromatherapy. This is a natural resin, a kind of resource available in Vietnam. Therefore, it is recommended for further research, exploitation, and effective use of this resource.

Polymorphism of methyl 4-amino-3-phenylisothiazole-5-carboxylate: an experimental and theoretical study

Being a close analogue of amflutizole, methyl 4-amino-3-phenylisothiazole-5-carboxylate (C11H10N2O2S) was assumed to be capable of forming polymorphic structures. Noncentrosymmetric and centrosymmetric polymorphs have been obtained by crystallization from a series of more volatile solvents and from denser tetrachloromethane, respectively. Identical conformations of the molecule are found in both structures. The two polymorphs differ mainly in the intermolecular interactions formed by the amino group and in the type of stacking interactions between the π-systems. The most effective method for revealing packing motifs in structures with intermolecular interactions of different types (hydrogen bonding, stacking, dispersion, etc.) is to study the pairwise interaction energies using quantum chemical calculations. Molecules form a column as the primary basic structural motif due to stacking interactions in both polymorphic structures under study. The character of a column (straight or zigzag) is determined by the orientations of the stacked molecules (in a `head-to-head' or `head-to-tail' manner). Columns bound by intermolecular N—H...O and N—H...N hydrogen bonds form a double column as the main structural motif in the noncentrosymmetric structure. Double columns in the noncentrosymmetric structure and columns in the centrosymmetric structure interact strongly within the ab crystallographic plane, forming a layer as a secondary basic structural motif. The noncentrosymmetric structure has a lower density and a lower (by 0.59 kJ mol−1) lattice energy, calculated using periodic calculations, compared to the centrosymmetric structure.

Robust pyridylbenzoate metal-organic frameworks as sorbents for volatile solvents and gases

Two activated isostructural porous compounds, [Co(34pba)(44pba)]n (1d) and [Zn(34pba)(44pba)]n (2d) (where 34pba is 3-(pyridin-4-yl)benzoate, 44pba is 4-(pyridin-4-yl)benzoate, and d indicates the activated phase) were used for the adsorption of halogenated...