[en] We visualized experimentally the internal flow inside inkjet droplets of polystyrene–anisole solution during solid film formation on substrates at room temperature. The effects of contact angle and evaporation rate on the internal flow and film morphology were quantitatively investigated. The transport process during film formation was examined by measuring the relationship between internal flow and film morphology, which provided three remarkable findings. First, self-pinning and the strength of outward flow on the free surface under 2.3 Pa s determined film morphology. The solute distribution, corresponding to rim areas in ring-like films and a convex trough in dot-like films, had already developed at self-pinning. Second, the mass fraction at self-pinning close to the contact line converged to one, regardless of the film morphology. This implies that self-pinning is independent of parameters such as the contact angle and evaporation rate. Third, at room temperature, the solutal Marangoni numbers were 20–30 times larger than the thermal ones. Thus, the outward flow on the free surface caused by the solutal Marangoni effect dominates in droplets before self-pinning. The solutal Marangoni number at self-pinning and thickness variation at the center of the film displayed a good relationship for droplets with different contact angles and evaporation rates. This suggests that film morphology can be technically controlled by solutal Marangoni number at room temperature.

[en] The solvolysis rate constants of 3,4- (1) and 3,5-dimethoxybenzoyl (2) chlorides were measured in various pure and binary solvents at 25.0 .deg. C, and studied by application of the extended Grunwald-Winstein (G-W) equation, kinetic solvent isotope effect in methanolysis and activation parameters. The solvolysis of 1 was interpreted as the unimolecular pathway due to a predominant resonance effect from para-methoxy substituent like 4-methoxybenzoyl chloride (3), while that of 2 was evaluated as the dual mechanism, with unimolecular or bimolecular reaction pathway according to the character of solvent systems (high electrophilic/nucleophilic) chosen, caused by the inductive effect by two meta-methoxy substituents, no resonance one. In the solvolyses of 1 and 2 with two -OCH₃ groups, the resonance effect of para-methoxy substituent is more important to decide the mechanism than the inductive effect with other corresponding evidences

[en] Short communication

No abstract available

No abstract available

[en] Trihalogenated anisoles (THAs) that have been identified at low concentration levels (ngL^-1) in drinking water are suspected of causing odor episodes, which are a frequent source of complaint by consumers. Henry's law constant (K_H) is an important parameter in controlling the diffusion of organic compounds from the water to the vapor-phase, so its evaluation is of significance in the study of odor events. In this paper, the K_H of a wide range of trihalogenated anisoles - in its dimensionless form K^'_H - were calculated at two temperatures, 45 and 22deg. C using equilibration partitioning in a closed system and headspace microextraction (EPICS-SPME). Two methodological approaches, Ramachandran and Dewulf, were used for the assessment of the Henry's law constant. Nevertheless, to apply these methods to THAs, a relatively narrow headspace/water volume ratio range (80/1-8/1) is required. At these conditions, a linearity (r²) using Ramachandran's theoretical relationship from 0.9276 to 0.9989 was obtained and the variability (R.S.D.%) when Dewulf's theoretical relationship was employed was lower than 20% (n=5)

[en] Pyrolysis-gas chromatography/mass spectrometry (Pyrolysis-GC/MS) has been extensively used for characterizing the structural information of various macromolecules such as humic substances, woods, and synthetic polymers. Challinor improved the technique by introducing simultaneous pyrolysis and methylation with tetramethylammonium hydroxide (TMAH). As the technique offers a number of advantages over conventional pyrolysis, it has been used widely for the characterization of a wide variety of macro-organic molecules such as polysaccharides. Thermally assisted hydrolysis and methylation of carbohydrates by TMAH has been investigated. This approach has improved the separation by methylation of acidic functional group. Several researchers have demonstrated that the role of TMAH is not only the methylation of the pyrolysis products but also assisting in bond cleavage. Because TMAH possesses a strong basicity, highly basic conditions are likely to induce a variety of reactions. Pyrolysis technique using TMAH renders polar pyrolysis products volatile enough to be eluted from the GC column by subsequent online methylation

[en] This work focuses on kinetic studies of anisole and triethylamine trihydrofluoride (fluorinating agent) on platinum electrode and acetonitrile as solvent, in order to get a better understanding of their anodic behavior. Results show that both compounds can be oxidized and some kinetic parameters are calculated: the diffusion coefficient within the working media, the anodic electronic transfer coefficient and the apparent intrinsic heterogeneous electronic transfer constant. An unusual variation of these parameters occurs within the chosen reaction conditions, particularly by varying the triethylamine trihydrofluoride concentration. Preliminary experiments for anodic fluorination of dimethoxy ethane (DME) and anisole were carried out and even if results show a possible electrofluorination for the DME (classically used as solvent), there is no fluorination of anisole when electrochemical microreactor was used.

[en] Isoflavones (3-aryl-4H-1-benzopyran-4-ones) are found naturally in soybeans and many plants of the Leguminosae family. They have attracted much attention due to their biological activities, such as their anti-cancer, anti-inflammatory, and antifungal properties. Isoflavones intake through foods is important to human health, because they potentially regulate fatty acid metabolism and methoxy-substituted isoflavones in particular increase cell permeability. Isoflavones have also been synthesized by the coupling of 3-iodochromones with arylboronic acids. The condensation of 2'-hydroxyacetophenones with DMF dimethyl acetal formed 3-(dimethylamino)-2'-hydroxyphenylpropenones, which were cyclized using iodine to form 3-iodochromones. This process was followed by Suzuki coupling with arylboronic acids or aryl boronates to obtain isoflavones. The synthesis of isoflavones (6) from 5 was based on the formylation of the methylene group of 5 using DMF-POCl_3. Previously, the reaction of the DMF-POCl_3 complex on benzyl 2-hydroxyphenyl ketones led to isoflavones, for which DMF was used as the reagent and solvent for 18 h at gentle reflux

[en] Pulse radiolysis of deaerated 1,2-dichloroethane solutions of anisole, methylanisoles, and di(methoxyphenyl)alkanes provide two types of transient species. One is a transient with a λ_max around 470 nm which is commonly observed in all methoxyphenyl compounds as well as in other unsubstituted or corresponding methyl-substituted compounds and identified as dimer cations due to an interaction of π-electrons. The other is a transient with a broad band at 500-700 nm. The λ_max and the intensity of the band are dependent on the structure of the anisole derivatives and the transient was tentatively assigned to a novel type of dimer cation in which n-electrons of the methoxyl group participate in the complex formation. Pulse radiolysis of carbon tetrachloride solutions of above mentioned anisole and its derivatives provided a transient species in visible region which is assigned to a charge-transfer complex with chlorine atoms. The absorption band energy of the complex was dependent on the ionization potential of the anisole derivatives, but the correlation between E _hv vs IP was quite different from that of unsubstituted aromatic compounds. (author)