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Synthesis of N-Substituted Derivatives of N-(4-(N-
Aziz-Ur-Rehman, Maria Ayoub, Muhammad Athar Abbasi, Samreen Gul, Muhammad Ashraf, Rabia Hassan, Irshad Ahmad, Khalid Mohammed Khan
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In this study, a new series of N-alkyl/arakyl derivatives of N-(4-(N-(5-chloro-2-methoxyphenyl)sulfamoyl)phenyl)acetamide (5a-k) was synthesized and screened for enzyme inhibition activity. Target compounds, N-alkyl/arakyl sulfamoylacetamides (5a-k) were synthesized by stirring N-(4-(N-(5-chloro-2-methoxyphenyl)sulfamoyl)phenyl)acetamide (3) with different electrophiles (4a-k) in the presence of sodium hydride (NaH) and N, N-dimethylformamide (DMF). The structures of all the synthesized compounds have been deduced from their spectral (1H-NMR, IR, EI-MS) data. All the new compounds displayed antiurease activity to varying degree.
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Air pollution Monitoring in Urban Areas due to Hea
Mujtaba Hassan, Amir Haider Malik, Amir Waseem and Muhammad Abbas
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The present study deals with the air pollution caused by Industry and transportation in urban areas of Pakistan. Rawalpindi and Islamabad, the twin cities of Pakistan were considered for this purpose. The concentrations of major air pollutants were taken from different location according their standard time period using Air Quality Monitoring Station. Five major air pollutants were considered i.e., NO2, SO2, CO, O3 and PM2.5. The average mean values for all pollutants were taken on monthly and four monthly bases. The concentrations of NO2 and PM2.5 were exceeding the permissible limits as define by Environmental Protection Agency of Pakistan. Other pollutants concentrations were within the standard limits. Geographic Information System was used as a tool for the representation and analysis of Environmental Impacts of air pollution. Passquill and Smith dispersion model was used to calculate the buffer zones. Some mitigation measures were also recommended to assess the environmental and health Impacts because of PM2.5 and NO2.
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Influence of Dispersing Agent in Formation of Β-Dicalcium Silicate from Rice Husk
Syed Hassan Javed, Mohsin Kazmi, Umair Aslam and Nadeem Feroze
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Present experimental work describes the synthesis of β-dicalcium silicate from rice husk by using dispersing agent during formation of calcium hydro silicate (CSH) gel. The growth of CSH gel retards the impeller mixing phenomenon. This type of problem can be resolved by using dispersing agent. Amorphous silica was obtained from HCl treated rice husk. Calcination temperature of rice husk was maintained at 600 oC for 90 minutes. In the presence of water, amorphous silica was treated with calcium oxide by using 0.2 % dispersing agent to develop CSH gel. The CSH gel was developed in oven for 12 hours at 90 oC followed by drying at 105 oC for 12 hours in an oven. Dried gels were heated up to 900 oC to obtain beta form of dicalcium silicate. The CSH gel and β-dicalcium silicate were examined by XRD, FTIR, SEM and TGA. It was observed that by using pretreated rice husk truly amorphous silica can be obtained. It was also observed that dispersing agent facilitated the formation of CSH gel. Observations further revealed that such amorphous CSH gel started converting into beta form of dicalcium silicate at 600 oC.
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Comparative Hydrolysis Study of Acetylsalicylic Acid and Copper (II)-Acetylsalicylate by RP-HPLC Method
Muhammad Sher, Mohammad Saeed Iqbal, Muhammad Ajaz Hussain, Syed Gohar Taqi and Muhammad Rashid Hussain
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The hydrolysis of acetylsalicylic acid (ASA) and copper (II)-acetylsalicylate (CAS) was investigated by using a validated RP-HPLC method. Acetylsalicylic acid was hydrolyzed to (SA), where as CAS was hydrolyzed to ASA, SA, copper salicylate (CS), copper acetate and acetic acid. Comparison of hydrolysis was carried out by monitoring the concentration of SA, one of common hydrolysis product. The hydrolysis study was done in phosphate buffer solution in pH range from 3-11. The study was carried out at constant temperature to evaluate the effect of pH on both drugs. It was found that the hydrolysis rate of both drugs was same at pH value ranging from 3-11 as calculated from the Kapp and K values. However, there is a slight difference in the degradation of ASA and CAS as revealed from F-test. Results have indicated that CAS first hydrolyzes to acetylsalicylic acid which further hydrolyzes to SA, therefore availability of acetylsalicylic acid is increased.
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The Influence of Different Ions on the Phase Separation of Poly (Vinyl Alcohol) and Poly (Sodium 4-Styrene Sulphonate) in Aqueous Solution
Iram Bibi, Khalid Mahmood, Syed Sakhawat Shah, Rashid Saeed and Mohammad Siddiq
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In aqueous solution the phase separation behavior of mixture of PVA-PSSNa has been studied. The critical concentration at which macroscopic phase separation occur is 1.0 mol/L. The cloud point curve is typically of (lower critical solution temperature) LCST type. The driving force responsible for shifting the LCST is hydrogen bonding and hydrophobic interaction of the macromolecules. When both the polymers have close molecular weight the polymer hetero-association increases which in turn decreases the intramolecular interaction within PVA chains. Addition of Hofmeister series of salts enhances the formation of complex between PVA-PSSNa which in turn decreases the LCST of mixture of polymers. The decrease of the LCST is in the order Na2SO4 < NaF < NaCl < NaClO3 < NaNO3 < NaBr < NaSCN which is opposite to classical Hofmeister series. Chaotropic anions favour the formation of complex more than kosmotropic anions this is because chaotropes have low surface tension values as compared to kosmotropes which lead to strengthening of hydrophobic interaction and enhances the complex formation which in turn shift the LCST toward lower temperature.
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Optimizing the Shrinkage and Bursting Strength of Knitted Fabrics after Resin Finishing
Tanveer Hussain, Faiza Safdar, Ahsan Nazir and Kashif Iqbal
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Application of crosslinking resins is one of the effective methods used for improving the dimensional stability of cotton knitted fabrics. However, such an application often results in severe deterioration in the bursting strength of the treated fabrics. This study was undertaken for modeling and optimization of the shrinkage control and bursting strength of Lacoste Pique cotton knitted fabrics, using response surface methodology. A central composite experimental design was used to find out the optimum resin and softener concentrations along with the best curing time for maximum shrinkage control with minimum possible loss in the fabric bursting strength.
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Thermal and Thermo-Mechanical Behavior of Butyl based Rubber Exposed to Silicon Oil at Elevated Temperature
Shaukat Ali, Sadaf Ramzan, Ramsha Raza, Fiaz Ahmed, Shafiq Ullah, Rizwan Hussain and Saqib Ali
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Silica reinforced rubbers are used as chemical resistant seals at high temperature. In this study the effect of alkali and silicon oil on the thermal and thermo-mechanical properties of the silica reinforced butyl rubber exposed as an interface between two liquid media at elevated temperature is investigated. Rubber bladder containing alkaline solution was immersed in silicon oil at 195±5oC for multiple cycles and loss in its thermal, thermo-mechanical and mechanical properties were studied by TGA, DMA and Tinius Olsen Testing Machine supported by FTIR and Optical microscopy. It was observed that the thermal and thermo-mechanical properties of butyl rubber were negatively affected due to leaching out of silica filler embedded in an organic matrix at elevated temperature. The thermal stability of exposed rubber was decreased around 200oC and the loss of storage modulus was observed up to 99.5% at -59oC.
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An Update on Secondary Metabolites from Haloxylon Species
Azizuddin, Abdul Majeed Khan and Sana Mustafa
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Secondary metabolites have been isolated from the various species of the genus Haloxylon (Chenopodiaceae) including H. ammodendron, H. aphyllum, H. articulatum, H. griffithii, H. persicum, H. recurvum, H. salicornicum, H. schmittianum Pomel and H. scoparium. These compounds belong to the classes, fatty acids and their esters, triglycerides, alcohols, steroids and their glycosides, phenol derivatives, coumarins, alkaloids of different classes, monocyclic naphthene derivatives, terpenes and flavonoids, and their glycosides. This present review will discuss the secondary metabolites 1-107 of different classes isolated from Haloxylon species with biological activities up to 2010.
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Catalyst and Solvent Free, Microwave Assisted Synthesis of 3-Isoindolo-2-yl-2-Substituted Quinazolin-4(3H)-Ones
Rasool Khan, Mohammad Arfan, Imdadullah Mohammadzai and Mohammad Naeem
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In the present work, we document a new microwave asisted and direct thermal fussion method for preperation of 3-isoindolo-2-substituted-quinazolin-4(3H)-ones under solvent and catalyst free conditions. Both methods are much convineant, green and faster and high yielding. Microwave method was proved to be high yielding and faster as compared to the direct thermal fusion method.
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1,3-Disubstituted Ureas as Antiglycating Agents
Shahnaz Perveen, Sana Mustafa, Khalid Mohammed Khan and Muhammad Iqbal Choudhary
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Twenty one (21) 1,3-disubstituted urea derivatives were screened for their antiglycating potential and some of them displayed promising activity. Compound N-butyl-N’-(4-nitrophenyl)urea (6) and N-isopropyl-N’-(4-nitrophenyl)urea (18) exhibited excellent activity and could be investigated in search of medicines treating diabetes and associated complications.
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