合成CFC-12替代物HFC-134a的CrF3/AlF3催化剂的研究

考察了不同反应条件下ＨＣＦＣ－１３３ａ与ＨＦ在ＣｒＦ３／ＡｌＦ３催化剂作用下生成ＨＦＣ－１３４ａ的反应性能。需用ＧＣ－ＦＴＩＲ方法鉴定了产物的组成，探讨了副产物形成的原因，并进行了催化剂的稳定性试验。结果表明在ＨＦ／ＨＣＦＣ－１３３ａ流量比为１０和３５０℃和条件下，得到了较高的转化率和选择性。     

Solubility Measurements of Surfactants and Dissolution of Cytochrome c in 1,1,1,2‐Tetrafluoroethane Modified with Organic Solvents

The solubilities of four surfactants, sodium bis‐2‐ethylhexyl sulfosuccinate (AOT), cetyltrimethylammonium chloride, didodecyldimethylammonium bromide, and n‐dodecyltrimethylammonium chloride in liquid refrigerant 1,1,1,2‐tetrafluoroethane (R134a) modified with methanol, ethanol, and 2‐propanol were measured. The measurements were performed under 25 and 50 bar at 25 °C. The solubility of AOT was as high as 92 mM in R134a with addition of 2% ethanol. Cytochrome c molecules were then verified to be soluble in the AOT‐containing and ethanol‐modified R134a solution. Accordingly, liquid R134a is suggested as a potential extraction solvent for hydrophilic compounds.     

合成CFC-12替代物HFC-134a的CrF_3/AlF_3催化剂研究(Ⅴ)──CrF_3与AlF_3的相互作用

由于氟氯烃（ＣＦＣｓ）对大气臭氧层的破坏作用，使得开发ＣＦＣｓ无污染替代品的研究成为热门课题［１～４］．氢氟烃（ＨＦＣｓ，如ＨＦＣ－１３４ａ）是ＣＦＣｓ的理想替代物．在氟氯交换合成ＨＦＣ－１３４ａ的反应中，ＡｌＦ３基催化剂的活性、稳定性明显优于ＣｒＦ...     

合成CFC-12替代物HFC-134a用CrF_3/AlF_3催化剂的研究 Ⅳ.AlF3基催化剂的制备及性能

本文探讨了γＡｌＦ３的热稳定性和酸性以及活性组分Ｃｒ３＋含量与活性的关系．考察了研制的ＡｌＦ３基催化剂的活性、稳定性及再生性，并对催化剂反应前后的结构进行比较．结果表明，催化剂的强酸中心是ＨＣＦＣ１３３ａ氟化生成ＨＦＣ１３４ａ的活性中心，催化剂晶格的氟离子参与了氟氯交换反应．ＡｌＦ３基催化剂具有高的活性和稳定性，在３５０℃，经２４００ｈ连续运行后，催化剂的晶相结构及比表面积未发生明显的变化．催化剂有较高的热稳定性，在４００℃反应８００ｈ催化剂仍具有一定的活性（３０％）．催化剂结炭失活可在３５０℃通空气或空气与ＨＦ的混合气进行再生     

Vapour–liquid equilibrium data for the 1,1,1,2 tetrafluoroethane (R134a) + dimethyl ether (DME) system at temperatures from 293.18 to 358.15 K and pressures up to about 3 MPa

Isothermal vapour–liquid equilibrium data have been measured for the binary system R134a + DME at five temperatures between 293.18 and 358.15 K, and pressures between 0.4899 and 2.9442 MPa. The peculiarity of this system is the existence of an azeotrope with a minimum pressure, which disappears at 358.15 K. The experimental method used in this work is of the static-analytic type, taking advantage of two pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in the CENERG/TEP Laboratory. The data were obtained with uncertainties within ±0.02 K, ±0.0001 MPa and ±1% for molar compositions.

The isothermal P, x, y data are well represented with the Redlich and Kwong equation of state using the Mathias–Copeman alpha function and the Huron–Vidal mixing rules involving the NRTL model.     

On-line high-performance liquid chromatography method for analyte quantitation from pressurized metered dose inhalers

A sensitive and rapid, on-line reversed-phase high-performance liquid chromatographic method for quantitation of compounds at low concentrations in pressurized metered dose inhaler (MDI) systems was developed. Traditional methods for the quantitation of compounds in MDI formulations involve the opening of the MDI vial along with sample dilution prior to quantitation. The new method, reported in this study, involves a direct injection from the MDI vial into the needle injector port of a manual injector. Since there is no dilution step involved, this method can be used to quantitate low concentrations of compounds in MDIs with excellent precision. In addition, since the method requires a small injection volume of 5 microl, repeated analyses can be performed in order to generate multiple data points using the same MDI vial. Validation of the method was performed using ethanol-1,1,1,2-tetrafluoroethane (134a)-based MDIs. Beclomethasone dipropionate (BDP), a corticosteroid used for the treatment of asthma, was used as a model compound. Phase separation studies were conducted to investigate the miscibility of the ethanol-134a mixtures with different mobile phase solvent compositions. For the MDI systems in this study, an acetonitrile-water (90:10, v/v) mobile phase at a flow rate of 0.9 ml/min was found to give acceptable chromatography for BDP on a Apollo C18 5 microm, 150 mm x 4.6 mm column (Alltech Associates, Deerfield, IL, USA). Ultraviolet detection was done at 240 nm and the retention time of BDP was 2.7 min. The on-line HPLC method was characterized to be accurate, precise, sensitive, and specific.     

合成CFC-12替代物HFC-134a的CrF3/AlF3催化剂研究(V)——CrF3与AlF3的相互作用

由于氟氯烃(CFCs)对大气臭氧层的破坏作用,使得开发CFCs无污染替代品的研究成为热门课题.氢氟烃(HFCs,如HFC-134a)是CFCs的理想替代物.