BiOBr photocatalyzed decarboxylation of glutamic acid: reaction rates, intermediates and mechanism

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 55727-55730 ◽  
Author(s):  
Yanfen Fang ◽  
Hongwei Yang ◽  
Wei Zhou ◽  
Yue Li ◽  
David M. Johnson ◽  
...  

BiOBr-photocatalyzed degradation of glutamic acid starts from the direct oxidation of the amino-carboxyl end and leads initially to succinic acid. Both the O-atoms from O2 and H2O incorporate into this product.

1986 ◽  
Vol 1 (02) ◽  
pp. 111-116 ◽  
Author(s):  
R.D. Gdanski ◽  
L.R. Norman

1961 ◽  
Vol 7 (3) ◽  
pp. 177-191 ◽  
Author(s):  
HIROSHI OKADA ◽  
IWAO KAMEYAMA ◽  
SHINJI OKUMURA ◽  
TOSHINAO TSUNODA

1991 ◽  
Vol 46 (5-6) ◽  
pp. 398-406 ◽  
Author(s):  
H. Schäfer ◽  
K. Taraz ◽  
H. Budzikiewicz

Pseudomonas strains of the so-called fluorescent group usually produce several pyoverdins which differ only in the nature of a dicarboxylic acid bound amidically to the chromophor. For the pyoverdins isolated from the culture medium of Pseudomonas fluorescens 12 it is shown that succinic acid is an artefact formed by hydrolysis of succinic amide, and that a-ketoglutaric acid is transformed enzymatically to glutamic acid. This process is reversed after the phase of exponential growth of the bacteria. The ratio C4- vs. C5 -acids changes with the culture time and with increasing Fe3+ content of the medium in favor of the latter


1970 ◽  
Vol 25 (6) ◽  
pp. 587-589
Author(s):  
M. Kempfle ◽  
K.-O. Mosebach ◽  
C. Blanke

The activities of GluDH against glutamic acid (α-oxoglutarate) and against alanine (pyruvate) were compared unter various conditions. Diethylstilbestrole (DES) inhibited the oxidative deamination of glutamic acid at all enzyme concentrations investigated but its effect on the oxidative deamination of alanine was different. At small enzyme concentrations (<0.01 mg/ml) where there are only monomers of the enzyme (mol.-weight 310 000) DES inhibited analogously to its behaviour in the glutamic acid reaction. At high concentrations where almost only aggregated enzyme molecules are present, DES stimulated the deamination of alanine and the reductive amination of pyruvate, respectively. These observations are interpreted without assuming different conformations of the monomers obtained either by simple dilution or by treatment with DES. An interpretation is possible by conceiving the inhibition and liberation of the active sites to be events influencing the encymatic activity contrarily.


1974 ◽  
Vol 14 (04) ◽  
pp. 385-395 ◽  
Author(s):  
L.D. Roberts

Abstract A mathematical model is developed that yields the distance to which live aid may penetrate into a fracture under conditions in which the over-all reaction kinetics. The model is solved by an explicit finite-difference method, and the results are presented in graphical form. An example design presented in graphical form. An example design calculation is given for HC1 reaction in a dolomite fracture. Experimental data are presented for acid flow in limestone and dolomite laboratory - prepared fracture systems 4.1 t 9.7 ft long, at 71, 190, and 290F. From these experiments was determined a parameter appearing in the mathematical model-termed the effective mixing coefficient. The mixing coefficient has a minimum in the low Reynolds number region, indicating that rectilinear laminar flow is approached more closely just before the flow becomes turbulent. The mixing coefficient also appears to be dependent upon temperature in the laminar flow region. The mathematical solutions given in this paper are applicable to situations in which the over-all rate of acid reaction is not determined solely by mass transfer. Introduction Acids are widely used in the hydraulic fracturing of reservoirs to stimulate wells. Roughly speaking, the purpose of the acid is to selectively react with and dissolve portions of the fracture wall so that a finite fluid conductivity remains when the well is returned to production. One important variable that must be known in designing these acid fracturing treatments is the distance to which acid will penetrate the fracture before completely reacting penetrate the fracture before completely reacting and becoming spent. This distance is usually termed the acid penetration length and is an essential part of the information needed for predicting productivity after acidizing. Other important design variables include the dynamic fracture geometry and the residual fracture conductivity. Because of its importance in predicting stimulation ratios, acid penetration into a fracture has been studied by several investigators. Both static tests and dynamic tests have been used to predict acid reaction rates in fractures. It seems predict acid reaction rates in fractures. It seems reasonable that a dynamic acid reactor test will be useful for predicting acid spending rates, since the mass transfer rate in an actual fracture may be approached in this type of test. One experimental apparatus used for acid flow tests in parallel plate system such as that used by Barron et al. plate system such as that used by Barron et al. and by Williams and Nierode. In these tests, acid is pumped at a known flow rate through a fracture of known geometry and the inlet and outlet acid composition is measured. From the resulting information it is possible to predict acid penetration in a real fracture with the aid of a mathematical model having experimentally determined parameters. We present here the results of an investigation of the use of mathematical model for predicting acid spending a fracture. Using Williams and Nierode's approach to calculating acid penetration, we have extended their method to allow for the fact that the surface reaction rates of several acid-rock systems (e.g., HC1-dolomite) may be finite compared with the rate of mass transfer to the surface. Experimental data are presented for determining the parameters appearing in the mathematical model and a sample calculation illustrates its use. MATHEMATICAL MODEL FOR ACID FRACTURING The mathematical model presented here is a modification of that introduced by Williams and Nierode to allow for the occurrence of finite reaction rates. This modification makes it possible to calculate theoretical penetration distances for acid featuring when reaction kinetics are important as in the case of the HC1-dolomite reaction. Since an analytical solution of the model is not possible, a finite-difference method was developed and is presented in Appendix A. presented in Appendix A. The model for acid formula is fracturing is presented in Fig. 1. Here the acid leakoff velocity, presented in Fig. 1. Here the acid leakoff velocity, is assumed constant over the fracture length. SPEJ p. 385


Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 957
Author(s):  
Gwang-Mun Choi ◽  
Ki-Seok Jang ◽  
Kwang-Seong Choi ◽  
Jiho Joo ◽  
Ho-Gyeong Yun ◽  
...  

An epoxy-based solder paste (ESP) is a promising alternative to conventional solder pastes to improve the reliability of fine-pitch electrical joining because the epoxy encapsulates the solder joint. However, development of an appropriate epoxy formulation and investigation of its reaction mechanism with solder powder is challenging. In this study, we demonstrate a newly designed ESP consisting of diglycidyl ether of bisphenol F (DGEBF) resin, Sn-3.0 Ag-0.5 Cu (SAC305) solder powder, and L-glutamic acid (Glu), which is a proteinogenic amino acid for biosynthesis of proteins in living systems. The mechanism of the thermochemical reaction was explored and tentatively proposed, which reveals that the products of the reaction between SAC305 and Glu function as catalysts for the etherification of epoxides and alcohols produced by chemical bonding between DGEBF and Glu, consequently leading to highly crosslinked polymeric networks and an enhancement of impact resistance. Our findings provide further insight into the mechanism of the reaction between various formulations comprising an epoxy, amino acid, and solder powder, and their potential use as ESPs for electrical joining.


SPE Journal ◽  
2006 ◽  
Vol 11 (04) ◽  
pp. 488-496 ◽  
Author(s):  
Kevin C. Taylor ◽  
Hisham A. Nasr-El-Din ◽  
Sudhir Mehta

Summary It is generally assumed that the reaction of acid with limestone reservoir rock is much more rapid than acid reaction with dolomite reservoir rock. This work is the first to show this assumption to be false in some cases, because of mineral impurities commonly found in these rocks. Trace amounts of clay impurities in limestone reservoir rocks were found to reduce the acid dissolution rate by up to a factor of 25, to make the acid reactivity of these rocks similar to that of fully dolomitized rock. A rotating disk instrument was used to measure dissolution rates of reservoir rock from a deep, dolomitic gas reservoir in Saudi Arabia (275°F, 7,500 psi). More than 60 experiments were made at temperatures of 23 and 85°C and HCl concentration of 1.0 M (3.6 wt%). Eight distinctly different rock types that varied in composition from 0 to 100% dolomite were used in this study. In addition, the mineralogy of each rock disk was examined before and after each rotating disk experiment with an environmental scanning electron microscope (ESEM) using secondary and backscattered electron imaging and energy dispersive X-ray (EDS) spectroscopy. Acid reactivity was correlated with the detailed mineralogy of the reservoir rock. It was also shown that bulk anhydrite in the rock samples was converted to anhydrite fines by the acid at 85°C, a potential source of formation damage. Introduction A study of acid reaction rates and reaction coefficients of a dolomitic reservoir rock was recently reported by Taylor et al. (2004a). In that work, it was found that reaction rates depended on mineralogy and the presence of trace components such as clays. This paper examines in detail the relationship between acid reactivity and mineralogy of a deep, dolomitic gas reservoir rock. An accurate knowledge of acid reaction rates of deep gas reservoirs can contribute to the success of matrix and acid fracture treatments. Many studies of acid stimulation treatments of Formation K, a deep, dolomitic gas reservoir in Saudi Arabia, have been published (Nasr-El-Din et al. 2001, 2002a, 2002b; Bartko et al. 2003). It is generally assumed that the reaction of acid with limestone reservoir rock is much more rapid than acid reaction with dolomite reservoir rock during acidizing treatments. However, much of the reported data were obtained with pure limestones, dolomites, and marbles. These include calcite marble (CaCO3) (Lund et al. 1975; de Rozieres 1994; Frenier and Hill 2002), dolomite marble [CaMg(CO3)2] (Lund et al. 1973; Herman and White 1985), Indiana limestone (Mumallah 1991), St. Maximin and Lavoux limestones (Alkattan et al. 1998), Haute Vallée de l'Aude dolomite (Gautelier et al. 1999), Bellefonte dolomite (Herman and White 1985), San Andres dolomite (Anderson 1991), Kasota dolomite (Anderson 1991), and Khuff dolomite reservoir cores (Nasr-El-Din et al. 2002b). The effects of common acid additives on calcite and dolomite dissolution rates were reported in detail (Frenier and Hill 2002; Taylor et al. (2004b; Al-Mohammed et al. 2006). The effects of impurities such as clays on rock dissolution have not been reported.


Sign in / Sign up

Export Citation Format

Share Document