The results show that R32/R134a/R227ea and R32/R125/R227ea are comparable to R22 at value of COP and Qv. Moreover, the obvious superiority to R410A is that its condensation pressure is greatly reduced and even less than that of R22 which give this mixture much more advantage in replacement.
Establishes the lubricating-oilless laboratory bench to test and compare the condensation heat transfer performance of new Turbo-DWT copper tube and conventional inner-grooved Turbo-A one using R-22,R134a and R410A.
Under the conditions of superficial velocity 0.035 m·s-1(standard condition), the inlet temperature of condenser 240℃, outlet temperature 85℃, SO3 concentration in the converted gas 3000×10-6, the content of vapor 2%, the concentration of sulphuric acid reached 95.9%, and the condensation efficiency exceeded 99.6%, and the concentration of sulphuric acid mist in the tail gas was below the Chinese standard.
When the temperature is higher than 400 K,at the same temperature the descending order of the condensation coefficients for different models is SPCE,TIP4P,TIP3P,SPC and TIP5P,while the difference between the coefficients of TIP4P and TIP3P is tiny.
The test was measured at the condensation temperature of 38.6 ℃ with mass flux of 30 kg/h and 60 kg/h,quality of 0.2~0.8,and the constant heat flux of 15 kW/m2.The result indicates that the local heat transfer coefficients of microfin tube are about 1.7 times of those of the plain tube.
Five new 1, 1'-bis (1, 3-dioxo-long-chain alkyl ) ferrocenes with the general formula C5H4FeC5H4 (COCH2COCnH2n+1 )2 (n= 5-9) were synthesized by Claisen condensation of 1, 1'-diacetylferrocene with ester.
The condensation reactions of cyclohexanone with ethylene glycol by using SnCl 4·5H 2O,NaHSO 4·H 2O,FeCl 3·6H 2O and AlCl 3· x H 2O as catalyst were studied. It was found that SnCl 4·5H 2O and NaHSO 4·H 2O are effective catalysis for ketol reaction.
In the present investigation, 4-hydroxy-3-methylacetophenone, on condensation with appropriate aldehydes in methanolic potassium hydroxide solution, yielded the corresponding chalcones (CI-XI).
The base-catalyzed condensation of thioureas (1-3a-i) with acetone was carried out in the presence of bromine to afford the corresponding 1-(isomeric methyl) benzoyl-3-aryl-4-methyl-imidazole-2-thiones (4-6a-i) in good yield.
In the synthesis of Compound A, the reactive processes used by us included the protection of amino group of lysine, acetylation, and intramolecular cyclizative condensation reaction.
4-(2-Hydroxy-phenyl)-but-3-en-2-one (1) was prepared via condensation of salicylaldehyde with acetone, and then reaction of the ketone 1 with thiosemicarbazide was accompanied by cyclization to give substituted pyrazole (2).
2,5-Bihydrazino-1,3,4-thiadiazole (2) was synthesized by condensation of 2,5-bimercapto-1,3,4-thiadiazole (1) with hydrazine hydrate, and compound 2 reacted with acyl chloride to give 2,5-biacylhydrazino-1,3,4-thiadiazole derivatives (3a-3e).