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The flame structure and reaction zone size of the dimethyl ether/air premixed flame in a cylindrical furnace were experimentally and numerically investigated in this paper. Seven cases of flames with different operational parameters were involved to reveal the influences of excess air ratio and thermal load on the combustion behaviors. The simulations were conducted using the eddy dissipation concept (EDC) model with a reduced chemical kinetic mechanism including 39 species and 168 reversible reactions. The present work demonstrated that the fluid structure in the furnace consisted of the flame core area (FCA), recirculation zone I (RZ I), and recirculation zone II (RZ II). In addition, the fluid structure was coupled with heat and mass transfer phenomena in the furnace and had a considerable effect on them. The temperature in the FCA was mainly dependent on the excess air ratio. The temperature in RZ II was strongly affected by the thermal load. Moreover, the temperature at the furnace outlet was positively correlated with the thermal load. The species contents in the overall furnace were mainly dependent on the excess air ratio. The influence of the thermal load over the species contents was rather insignificant. Moreover, the intensified diffusion outside the flame zone resulting from the decrement of temperature could change the species distributions in part. Research on the reaction zone size indicated that either the decrease of excess air ratio or the increase of thermal load could result in an enlargement of the reaction zone. Additionally, the mean reaction rate of the dimethyl ether/air premixed flame was found to be independent of the thermal load. It was observed to be dependent on the excess air ratio. Finally, a functional expression between the mean reaction rate and the excess air ratio was developed in this paper.

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The solubility of calcium sulfate dihydrate (CaSO 4 •2H 2 O) was measured in NaCl and glycerol aqueous solution with the mass fraction of glycerol 0−80% and molality of NaCl 0−6 m in the temperature range of 303.15 to 343.15 K and atmospheric pressure. The results showed that the dissolution of CaSO 4 •2H 2 O obviously decreased in aqueous solution with the increase of glycerol content. Addition of NaCl increased the solubility of CaSO 4 •2H 2 O in glycerol aqueous solution, and then solubility decreased with a further increase of molality in which the solubility maximum increase rate is 246.15%. Temperature has a little effect on solubility in the CaSO 4 • 2H 2 O/NaCl/glycerol/H 2 O system. We also studied the physical properties (density and viscosity) of this system and used the least squares method to correlate the solubility, density, and viscosity with the molality of NaCl in a polynomial equation.

A novel green and efficient reaction route for the synthesis of 2‐chloroquinoline via N‐fluoride fluorinated by 1‐Chloromethyl‐4‐fluoro‐1,4‐diazoniabicyclo [2.2.2] octane bis(tetrafluoroborate) (Selectfluor) with 1,3‐Dichloro‐5,5‐dimethylhydantoin (DCDMH) in Vapourtec reactor has been developed. In addition, a series of C2 heterocyclic derivative products are obtained in moderate to good yields under no metal conditions.

The solubility of calcium sulfate dihydrate (DH) and α-calcium sulfate hemihydrate in formamide aqueous solutions with 0–13 m formamide at temperatures from 303.15 to 363.15 K was measured by the dissolution equilibrium method. Formamide has a solubilization effect similar to the salt effect; the solubility of calcium sulfate dihydrate and α-calcium sulfate hemihydrate first increases significantly as the concentration of formamide aqueous solution increases. When the solubility reaches the maximum value, it decreases gradually. The modified Apelblat–Jouyban–Acree model shows good agreement with experimental values; hence, it may be suitable in describing the solubility of calcium sulfate dihydrate and α-calcium sulfate hemihydrate in the formamide aqueous solution at the temperatures ranging from 303.15 to 363.15 K under 88.35 kPa. On comparing the solubility of calcium sulfate dihydrate and α-calcium sulfate hemihydrate in the formamide aqueous solution, it was found that the solubility of α-calcium sulfate hemihydrate is lower than that of calcium sulfate dihydrate, being above 8.3418 and 3.7286 mol·kg–1 when the temperatures are 353.15 and 363.15 K, respectively, which is beneficial to the conversion of calcium sulfate dihydrate into α-calcium sulfate hemihydrate.

Welan gum has disadvantages such as poor solubility, low viscosity, and poor crosslinking property, when it is applied in petroleum industry, comparing to guar gum. Two methods for the carboxylic modification of welan gum were developed, carboxyethyl modification and citric acid modification, to improve the solubility in water, viscosity, and crosslinking ability of welan gum in the borax crosslinking system. The solubility time of carboxyethyl modified and citric acid modified welan gum were shortened to 30 and 90 min, respectively. The highest viscosity of citric acid modified product was 49.4 mPa s, the viscosity after crosslinking was raised at least 1.2 times to the highest four times than that before crosslinking. The results indicated three factors affecting the properties of modified products: (1) how many function groups in the modifying agent; (2) the way to connect the function group; and (3) the whole structure of the modifying agent.