THE SEPARATION AND DETERMINATION OF THE ALKALI METALS USING PERCHLORIC ACID. II. THE PRECISE ESTIMATION OF THE INSOLUBLE ALKALI METAL PERCHLORATES

1925 ◽  
Vol 47 (3) ◽  
pp. 774-781 ◽  
Author(s):  
G. Frederick Smith ◽  
John F. Ross
Keyword(s):  
Alkali Metal ◽  
Perchloric Acid ◽  
Alkali Metals ◽  
Precise Estimation

Hydrothermal Liquefaction of Enteromorpha prolifera for Bio-Crude Production: An Experimental Study on Aqueous Phase Recirculation

2019 ◽  
Vol 62 (5) ◽  
pp. 1113-1119 ◽  
Author(s):  
Jixiang Zhang ◽  
Cheng Qian ◽  
Kelei Yan ◽  
Jianfei Song ◽  
Baohui Jiang
Keyword(s):  
Experimental Study ◽  
Alkali Metal ◽  
Aqueous Phase ◽  
Alkali Metals ◽  
Hydrothermal Liquefaction ◽  
Enteromorpha Prolifera ◽  
Catalyst Recycling ◽  
Catalyst Dosage

Abstract. In this study, catalytic hydrothermal liquefaction (HTL) of with aqueous phase recirculation (APR) was tested in order to improve bio-crude yield and reduce catalyst dosage. Bio-crude yields of 17.0% and 18.5% were obtained at 300°C in 30 min of non-catalytic HTL and catalytic HTL with 5.0% NaOH, respectively. Determination of alkali metals showed that 76.7% of the Na was recovered in the aqueous phase, indicating that APR provided the possibility for catalyst recycling. Bio-crude yields were increased to 20.0% and 22.7% when performing APR for non-catalytic and catalytic HTL, respectively. To investigate the effects of recycled catalyst and volatile aqueous products (VAPs), a different APR experiment with VAPs removal for catalytic HTL was conducted, and a bio-crude yield of 17.8% was achieved. It was concluded that bio-crude yield increased with APR, mainly due to the effects of VAPs. Keywords: Alkali metal, Aqueous phase recirculation, Hydrothermal liquefaction.

Van der Waals and repulsive interactions in the crystal structure of heavy alkali metals

1980 ◽  
Vol 58 (6) ◽  
pp. 905-911 ◽  
Author(s):  
J. C. Upadhyaya ◽  
S. Wang ◽  
R. A. Moore
Keyword(s):  
Crystal Structure ◽  
Binding Energy ◽  
Alkali Metal ◽  
Alkali Metals ◽  
High Pressures ◽  
Van Der Waals ◽  
Energy Difference ◽  
Repulsive Interactions

The present work deals with the calculation of a screened van der Waals contribution to the binding energy of heavy alkali metals, namely K, Rb, and Cs. Our calculations show that the van der Waals contribution is of the order of energy difference between different phases for a heavy alkali metal. Further we study the effect of the Born–Mayer type repulsive interactions on the crystal structure for heavy alkalis. It appears from this study that these repulsive interactions are important in the determination of the crystal structure, particularly for a heavy alkali metal under high pressures.

Room Temperature Alkali Metal Reduction of Carbon Dioxide

2020 ◽  
Author(s):  
Lucas A. Freeman ◽  
Akachukwu D. Obi ◽  
Haleigh R. Machost ◽  
Andrew Molino ◽  
Asa W. Nichols ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Alkali Metals ◽  
Room Temperature ◽  
Chemical Reduction ◽  
Bond Cleavage ◽  
Open Shell ◽  
Metal Reduction ◽  
One Pot ◽  
Earth Abundant ◽  
Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO<sub>2</sub> to access useful CO<sub>2</sub>-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO<sub>2</sub> and the MGE. Herein we report the first successful chemical reduction of CO<sub>2</sub> at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO<sub>2</sub> adduct (<b>1</b>) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO<sub>2</sub>)]<sub>n</sub>(M = Li, Na, K, <b> 2</b>-<b>4</b>) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M<sub>2</sub>(CAAC–CO<sub>2</sub>)]<sub>n </sub>(<b>5</b>-<b>8</b>). It is notable that these crystalline clusters of reduced CO<sub>2</sub> may also be isolated via the “one-pot” reaction of free CO<sub>2</sub> with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products <b>2</b>-<b>8</b> were investigated using a combination of experimental and theoretical methods.<br>

Deproteinizing methods evaluated for determination of uric acid in serum by reversed-phase liquid chromatography with ultraviolet detection.

1987 ◽  
Vol 33 (8) ◽  
pp. 1427-1430 ◽  
Author(s):  
R Sakuma ◽  
T Nishina ◽  
M Kitamura
Keyword(s):  
Uric Acid ◽  
Liquid Chromatography ◽  
Perchloric Acid ◽  
High Performance ◽  
Reversed Phase ◽  
Precipitation Method ◽  
Zinc Hydroxide ◽  
Good Precision ◽  
Ultraviolet Detection

Abstract We evaluated six deproteinizing methods for determination of uric acid in serum by "high-performance" liquid chromatography with ultraviolet detection: those involving zinc hydroxide, sodium tungstate, trichloroacetic acid, perchloric acid, acetonitrile, and centrifugal ultrafiltration (with Amicon MPS-1 devices). We used a Toyosoda ODS-120A reversed-phase column. The mobile phase was sodium phosphate buffer (40 mmol/L, pH 2.2) containing 20 mL of methanol per liter. Absorbance of the eluate was monitored at 284 nm. The precipitation method with perchloric acid gave high recoveries of uric acid and good precision, and results agreed with those by the uricase-catalase method of Kageyama (Clin Chim Acta 1971;31:421-6).

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