260 research outputs found
One-pot Synthesis of Substituted Pyrroles with N,N,N’,N’-Tetrachlorobenzene-1,3-disulphonamide and N,N’-Diiodo-N,N’-1,2-ethanediylbis(p-toluenesulphonamide) as Novel Catalytic Reagents
In this research, N,N,N’N’-tetrachlorobenzene-1,3-disulphonamide as novel catalytic reagent and N,N’-diiodo-N,N’-1,2-ethanediylbis(p-toluenesulphonamide) as new catalyst were used for the synthesis of N-substituted pyrroles in good to excellent yields under mild conditions. These reusable reagents were compared with existing reagents and it is clear that this study is a welcome addition in the field of pyrrole synthesis.Keywords: Pyrroles, Paal-Knorr reaction, TCBDA, NIBTS, catalytic reagen
Comparison of survival and larvae physiological resistance of white shrimp, Litopenaeus vannamei, fed with live food (rotifer and Artemia urmiana) and concentrated food
Anemia nauplii and rotifier are considered as the most important live food in aquaculture because of their high nutritional quality, suitable size and mobility. The survival rate and resistance of white shrimp (Litopenaus vannamei) postlarvae fed by Artemia urmiana, Brachinus plicatilis and concentrated food were investigated. Larvae at the stage of Protozoae 1 were stocked in 14 liters plastic containers filled by 6 liters of water. There were 75 larvae per liter in each container. The larvae were fed in 3 treatments: T1 (rotifier), T2 (Artemia) and T3 (concentrated food). Each treatment was repeated 3 times and used during Protozoae 1 (PLC} to Post-larvae 5 (PLO stages. Data analysis was done through Duncan Test. We observed that from Mysis 1 stage to PL1 the rotifier can be used for shrimp feeding and from this stage to PL5, Artemia nauplii can be used as food for the larvae. To evaluate the quality of larvae, the physiological resistance tests were conducted against formalin and salinity in different periods of time (30, 60 and 90 minutes). We found that at the PLC stage, the maximum survival (100%) in formalin tests (I 0Oppm) and (200ppm) and salinity test (15ppt) was related to feeding the shrimp larvae with rotifier. However, at the PL5 stage, the maximum survival (100%) under the same conditions was related to application of Artemia nauplii food. The concentrated food showed the minimum survival in all tests
Solvent-free Oxidation of Alcohols and Mild Catalytic Deprotection of Silyl Ethers with Poly(N,N’-dibromo-N-ethyl-benzene-1,3-disulphonamide) and N,N,N’,N’-tetrabromobenzene-1,3-disulphonamide
Poly(N,N’-dibromo-N-ethyl-benzene-1,3-disulphonamide) (PBBS) and N,N,N’,N’-tetrabromobenzene- 1,3-disulphonamide (TBBDA) can be used for solvent-free oxidation of primary and secondary alcohols to the corresponding carbonyl compounds without over-oxidation, and efficient catalytic deprotection of various silyl ethers to hydroxyl groups in aprotic organic solvents under ambient conditions.KEYWORDS: Solvent-free oxidation, alcohols, catalytic deprotection, silyl ethers, PBBS, TBBDA
Production of soybean meal-based feed and its effect on growth performance of western white shrimp (Litopenaeus vannamei) in earthen pond
The effects of two diets, a control diet (commercial feed with 39% crude protein) and an experimental diet (prepared based on 42% soybean meal with 38% crude protein), on growth performance of western white shrimp (Litopenaeus vannamei) in six 0.4-ha-earthen ponds (three replications per treatment) with 25 per m^2 density, were investigated. There was no significant difference in final weight (mean final weights were 15.7±0.88 and 15.6±0.52 g for the experimental and control treatments, respectively) between the treatments during the 115 days rearing period. There were no difference in FCR: 1.80±0.08 and 1.76±0.06, protein efficiency: 1.46±0.01 and 1.45±0.05, SGR: 2.38±0.04 and 2.38±0.03, final production: 2853.58±64.14 and 2864.83±168.57 kg/ha and survival rate: 91±1.78, 92±2.41% between experimental and control treatments, respectively (p>0.05) but net protein utilization in experimental treatment (17.05±0.38 g) and in the control (11.80±0.26 g) revealed significant differences (p<0.05). It is concluded that the experimental feed with 42% soybean meal was more efficient than the commercial feed on some growth parameters of western white shrimp
Facile and mild deprotection of semicarbazones under solvent-free conditions with N,N,N',N'-tetrabromo-benzene-1,3-disulfonylamide
Comparative study of the effects of HUFA in dry diets and natural foods on fecundity and egg diameter of female broodstock of white leg shrimp (Litopenaeus vannamei)
During 2 months (from April to June, 2008) we studied the suitable quantity of Highly Unsaturated Fatty Acids (HUFA) for desirable fecundity and egg diameter of female broodstock of white leg shrimp (Litopenaeus vannamei). Similar dry food containing Isonitrogeneous material (31.5% protein) and Isolipid (6.9% lipid) was used but with different levels of HUFA (1, 2 and 3%). Also, the HUFA of natural foods (Perinereis worm, melalis bivalvia and cuttlefish) was analyzed. We compared the effects of four levels of dietary HUFA (1, 2 & 3 % HUFA of dry diets and the average HUFA of natural diets) on fecundity and egg diameter of female broodstock of white leg shrimp. The fecundity and egg diameter of natural diet and HUFA 3% were not significantly different (P>0.05). The fecundity of natural diet and HUFA 3% was significantly higher than the other two treatments (P<0.05) and also the egg diameter of HUFA 3% and natural diet was significantly higher than the other two treatments (P<0.05). According to the results of fecundity and egg diameter measurements, both natural and HUFA 3% diets are suggested as suitable for white leg shrimp breeding
Immobilization of palladium nanoparticles as a recyclable heterogeneous catalyst for the Suzuki–Miyaura coupling reaction
Highly Efficient Formylation of Alcohols, Thiols and Aniline Derivatives by a Heterogeneous (HCOOH/SiO2) System under Microwave Irradiation and Solvent-free Conditions
A simple, rapid and efficient microwave-assisted procedure for the formylation of aniline derivatives and alcohols, using a heterogeneous (HCOOH/SiO2) system under solvent-free conditions is reported. The method is applied to a set of amines, alcohols and thiols and short reaction times (<10 min) with high yields are reported. This protocol introduces a practical and viable green technology of solvent-free and catalyst-free reactions.Keywords: Alcohols, anilines, SiO2, HCOOH, microwave irradiation, solvent-free condition
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