Effects of metal and porphyrin structure on the yield and chemoselectivity of naphthalene oxidation: a comparative study for manganese and iron

2005 ◽  
Vol 09 (02) ◽  
pp. 75-81 ◽  
Author(s):  
Hamid Reza Khavasi ◽  
Nasser Safari
Keyword(s):  
Catalytic Activity ◽  
Comparative Study ◽  
Aprotic Solvent ◽  
Iron Porphyrin ◽  
Manganese Porphyrin ◽  
Iron Porphyrins ◽  
Tert Butylhydroperoxide ◽  
Excess Amount ◽  
Naphthalene Oxidation ◽  
Better Than

Oxidation of naphthalene was performed with various manganese and iron porphyrins as catalysts and metachloroperbenzoic acid, tert-butylhydroperoxide, and hydrogenperoxide as oxidants, in the presence of imidazole as cocatalyst. With m-CPBA, in low concentration of catalyst, iron porphyrin shows a higher catalytic activity than manganese porphyrin, while a greater amount of manganese porphyrin is needed for having a good catalyst. In the presence of excess amount of H 2 O 2 oxidant in CH 3 OH solvent, manganese porphyrin acts better than iron porphyrin; however with the same oxidant and in aprotic solvent such as CH 3 CN : CH 2 Cl 2 again iron shows a higher activity than manganese. Moreover, the effects of metalloporphyrin concentration on the selectivity, activity and stability of catalyst were studied in H 2 O 2-catalytic oxidation.

Comparative Study Between Clean Intermittent Self-Catheterization (Cisc) and Continuous Indwelling Catheterization (Cidc) in Relieving Acute Refractory Retention of Urine Due to Benign Enlargement of Prostate (Bep)

2020 ◽  
Vol 21 (2) ◽  
pp. 105-110
Author(s):  
Md Shawkat Alam ◽  
Sudip Das Gupta ◽  
Hadi Zia Uddin Ahmed ◽  
Md Saruar Alam ◽  
Sharif Muhammod Wasimuddin
Keyword(s):  
Comparative Study ◽  
Acute Urinary Retention ◽  
Bladder Capacity ◽  
Inclusion Criteria ◽  
College Hospital ◽  
Medical College ◽  
High Incidence ◽  
Group A ◽  
Group B ◽  
Better Than

Objective: To compare the clean intermittent self-catheterization (CISC) with continuous indwelling catheterization (CIDC) in relieving acute urinary retention (AUR) due to benign enlargement of prostate (BEP). Materials and Methods :A total 60 patients attending in urology department of Dhaka Medical college hospital were included according to inclusion criteria ,Patients were randomized by lottery into two groups namely group –A and group –B for CISC and IDC drainage respectively . Thus total 60 patients 30 in each group completed study. Results : Most men can safely be managed as out-patients after AUR due to BPH. The degree of mucosal congestion and inflammation within the bladder was found to be lower in those using CISC and the bladder capacity in these patients was also found higher.Patients with an IDC had a high incidence of UTIs then that of patients with CISC. During the period of catheterization the incidence of UTI was 43.3% in group B in comparison to 40% in group A; before TURP 36% in group B in comparison to 10% incidence in group A.According to patient’s opinion CISC is better than IDC in the management of AUR. Experiencing bladder spasm, reporting blood in urine, management difficulties, incidence and severity of pain were less in CISC group, and the method of CISC was well accepted by patients as well as their family members. Conclusion: From the current study it may be suggested that CISC is better technique for management of AUR patient due to BPH than IDC. It can also be very helpful when surgery must be delayed or avoided due to any reasons in this group of patients. Bangladesh Journal of Urology, Vol. 21, No. 2, July 2018 p.105-110

Cr-Substituted Mesoporous Aluminophosphate Molecular Sieve: Synthesis, Characterization, Crystallization Kinetics and Catalytic Activity

2013 ◽  
Vol 316-317 ◽  
pp. 1018-1023
Author(s):  
Xin Zhu Li ◽  
Ji Shi Zhang
Keyword(s):  
Activation Energy ◽  
Catalytic Activity ◽  
Crystal Growth ◽  
Crystallization Kinetics ◽  
Molecular Sieve ◽  
Arrhenius Equation ◽  
Degree Of Crystallinity ◽  
Tert Butylhydroperoxide ◽  
Growth Activation ◽  
Cr Map

Cr-substituted mesoporous aluminophosphate molecular sieve (Cr-MAP) was synthesized and characterized. Crystallization kinetics curves measured as an index to the relative degree of crystallinity, according to the Arrhenius equation to calculate the apparent nucleation activation energy and crystal growth activation energy of Cr-MAP, which was 63.7 and 14.7 kJ• mol-1, respectively. Cr-MAP had highly catalytic activity for fabricating acetophenone by selectively oxizing ethylbenzene. Using tert-butylhydroperoxide as oxidant and chlorobenzene as solvent at 100 °C for 8 h, acetophenone selectivity, acetophenone yield and ethylbenzene conversion reaches 85.4, 62.2 and 72.8 %, respectively.

A facile approach to fabricate halloysite/metal nanocomposites with preformed and in situ synthesized metal nanoparticles: a comparative study of their enhanced catalytic activity

2015 ◽  
Vol 44 (19) ◽  
pp. 8906-8916 ◽  
Author(s):  
Sankar Das ◽  
Subhra Jana
Keyword(s):  
Catalytic Activity ◽  
Comparative Study ◽  
Metal Nanoparticles ◽  
Heterogeneous Catalysts ◽  
Cost Effective ◽  
Environmentally Benign ◽  
Metal Nanocomposites

Halloysite/metal nanocomposites have been synthesized through the immobilization of preformed and in situ synthesized metal nanoparticles over halloysite surfaces, which in turn produce efficient, cost-effective, and environmentally benign heterogeneous catalysts.

A comparative study of the catalytic activity of Co- and CoFe2O4-NPs in C–N and C–O bond formation: synthesis of benzimidazoles and benzoxazoles from o-haloanilides

2016 ◽  
Vol 40 (12) ◽  
pp. 10474-10481 ◽  
Author(s):  
Abdol R. Hajipour ◽  
Zahra Khorsandi
Keyword(s):  
Catalytic Activity ◽  
Comparative Study ◽  
Bond Formation ◽  
New Methods ◽  
Comparison Of The Results

Herein, new methods and a comparison of the results for dehalogenative intramolecular C–X bond formation using two inexpensive and efficient catalysts are reported.

scholarly journals Work Value among Married and Unmarried Person’: A Comparative Study

2014 ◽  
Vol 1 (2) ◽  
Author(s):  
Ramesh O. Prajapati
Keyword(s):  
Data Collection ◽  
Comparative Study ◽  
T Test ◽  
Nuclear Families ◽  
Significant Difference ◽  
Low Incomes ◽  
Result Show ◽  
Work Value ◽  
Test Result ◽  
Better Than

Aim of the research is to find out the Work value among married and unmarried person’s. So investigator selected two groups one is married and other is unmarried persons, both groups have 200 persons. In one group has 113 married and other one groups has 87 unmarried persons. The all subjects were randomly selected. Data were collected from Ahmadabad district. Scale was use for data collection is personal datasheet and Work value scale developed by super (1970) and this scale was translated into Gujarati by Jalawadiya (2002), and data were analysis by ‘t’ test. Result show, There is no significant mean difference of Work value between married and unmarried persons. There is no significant difference of the Work value of joint and nuclear families. The high income persons work value is better than the low incomes.

scholarly journals Chiral MnIII (Salen) Immobilized on Organic Polymer/Inorganic Zirconium Hydrogen Phosphate Functionalized with 3-Aminopropyltrimethoxysilane as an Efficient and Recyclable Catalyst for Enantioselective Epoxidation of Styrene

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 212 ◽  
Author(s):  
Xiaochuan Zou ◽  
Yue Wang ◽  
Cun Wang ◽  
Kaiyun Shi ◽  
Yanrong Ren ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Supported Catalysts ◽  
Organic Polymer ◽  
Solid Catalyst ◽  
Homogeneous Catalyst ◽  
Hydrogen Phosphate ◽  
Characterization Methods ◽  
Salen Complexes ◽  
Enantioselective Epoxidation ◽  
Better Than

Organic polymers/inorganic zirconium hydrogen phosphate (ZSPP, ZPS-IPPA, and ZPS-PVPA) functionalized with 3-aminopropyltrimethoxysilane were prepared and used to support chiral MnIII (salen) complexes (Jacobsen’s catalyst). Different characterization methods demonstrated that the chiral MnIII (salen) complexes was successfully supported on the surface of the carrier (ZSPP, ZPS-IPPA, or ZPS-PVPA) through a 3-aminopropyltrimethoxysilane group spacer. The supported catalysts effectively catalyzed epoxidation of styrene with m-chloroperbenzoic acid (m-CPBA) as an oxidant in the presence of N-methylmorpholine N-oxide (NMO) as an axial base. These results (ee%, 53.3–63.9) were significantly better than those achieved under a homogeneous counterpart (ee%, 46.2). Moreover, it is obvious that there was no significant decrease in catalytic activity after the catalyst 3 was recycled four times (cons%: from 95.0 to 92.6; ee%: from 64.7 to 60.1). Further recycles of catalyst 3 resulted in poor conversions, although the enantioselectivity obtained was still higher than that of corresponding homogeneous catalyst even after eight times. After the end of the eighth reaction, the solid catalyst was allowed to stand in 2 mol/L of dilute hydrochloric acid overnight, prompting an unexpected discovery that the catalytic activity of the catalyst was recovered again at the 9th and 10th cycles of the catalyst.

A Canadian Comparative Study of Modified Versions of the “FDA” and “USDA” Methods for the Detection of Listeria monocytogenes

1991 ◽  
Vol 54 (9) ◽  
pp. 669-676 ◽  
Author(s):  
DONALD W. WARBURTON ◽  
JEFFREY M. FARBER ◽  
ANDREW ARMSTRONG ◽  
RICARDO CALDEIRA ◽  
NARAYAN P. TIWARI ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Comparative Study ◽  
Lithium Chloride ◽  
Environmental Samples ◽  
Screening Tool ◽  
Significant Difference ◽  
Better Than

Eleven laboratories across Canada took part in a comparative study of modified versions of the “FDA” and “USDA” methods for the detection of Listeria monocytogenes in foods and environmental samples. Both were modified by the inclusion of additional plating media and the use of modified Fraser broth in the modified “FDA” method. Approximately 92% of the positive samples were detected after 24 h of enrichment. Testing of routine samples by the participating laboratories showed no significant difference (p<0.05) in ability to isolate L. monocytogenes by either the modified “FDA” or “USDA” methods. However, the modified “FDA” method isolated significantly more positives (16.8%) from the spiked foods/controls than the modified “USDA” method (p<0.05). For all samples tested by both methods in the same laboratory, again the modified “FDA” method significantly out performed the “USDA” version by approximately 6% (p<0.05). However, the spiked foods/controls tested by both methods in the same laboratory showed no difference (p<0.05) in their ability to isolate L. monocytogenes. Overall, the modified “FDA” and “USDA” methods were comparable (within 1.0%) in their ability to isolate this microorganism. The “USDA” preenrichment broth maintained its initial pHbetter. Modified Fraser broth, in principle, proved to be useful as a screening tool but is not very selective. Oxford agar proved to be marginally better than lithium chloride-phenylethanol-moxalactam medium and significantly (p<0.05) better than modified Oxford agar in isolating L. monocytogenes.

scholarly journals A comparative study on tissue response under the ridgelap and modified ridgelap pontic

2015 ◽  
Vol 5 (1) ◽  
pp. 15-20
Author(s):  
Md Ali Afzal Khan ◽  
Mahabubur Rahman ◽  
Kazi Ziaul Islam ◽  
Newaz Mohsina ◽  
Md Ashif Iqbal ◽  
...  
Keyword(s):  
Comparative Study ◽  
Mucous Membrane ◽  
Tissue Response ◽  
Partial Denture ◽  
Fixed Partial Denture ◽  
Tissue Surface ◽  
Fixed Prosthesis ◽  
Cementing Material ◽  
Missing Tooth ◽  
Better Than

The aim of this study is to compare the tissue response between the ridgelap pontic and modified ridgelap pontic. Total patients were 40. The fixed prosthesis were cemented by temporary cementing material. After providing the treatment, instruction on maintenance of prosthesis. Patients were visited and studied after 6 weeks, 12 weeks and 6 months to observe the condition of tissue response beneath pontic. The following necessary data were collected in respect of the condition of tissue beneath the pontic, color of gingiva. The modified ridgelap pontic is better than ridgelap pontic regarding tissue response. The tissue response with the ridgelap surface of the pontic of fixed partial denture in 1st molar missing tooth enhanced the condition of the mucous membrane beneath the tissue surface of the pontic, condition of the abutment tooth, between ridge surface of the pontic and mucosa overlying the edentulous ridge achieved better success regarding fixed partial denture.Update Dent. Coll. j: 2015; 5 (1): 15-20

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