کُتبِ اُصول حدیث اکیسویں صدی میں ؛ایک تعارفی جائزہ An Introductory Review of the Books written on ‘Usūl e Ḥadīth in 2ist Century

Muslims are a unique nation in the world who have shown unparalleled activism in preserving their sayings and relics. Caution was in view from day one. The simple precautionary measures taken in the early days later took the form of theology. In the beginning, the principles and rules of this knowledge did not exist in a disciplined form, although the scholars of Muḥaddithin adhered to the basic principles of this knowledge from the very beginning. However, references to these principles were to be found in the books of the pious. In the 4th Hijri, the scholars of Muhaddithin compiled the previous scattered work on the art of the principle of Ḥadith. Now these comprehensive definitions and terms are before us in a systematic and disciplined form in the books of ‘Usūl e Ḥadīth. In this short essay, the definition and necessity and importance of Hadith and ‘Usūl e Ḥadīth have been highlighted and also an introductory review of books written on ‘Usūl e Ḥadīth th and their authors and authors has been presented. Which indicates this. How strict were the rules and regulations of the Muslim Ummah for examining the authenticity and text of the Holy Hadith and how did they separate the authentic, weak and subject matter of the hadiths and write their separate books? And how hard they have worked to promote art.

Catalytic Hydrocracking of Waste Plastics to Liquid Fuels

The worldwide production of plastic products has been increasing rapidly over the last few decades. This increase in plastic production has resulted in gigantic amount of plastic waste. Conventional methods for waste plastic management such as landfilling and incineration are susceptible to many environmental hazards that necessitate the need of recycling of plastic wastes. Chemical recycling methods are encouraged all over the world and hydrocracking is the most advantageous process among them. Hydrocracking occurs at low temperatures and converts waste plastics into high quality liquid fuel. In the present work, hydrocracking of a municipal waste model plastic mixture is studied using inhouse synthesized mesoporous and composite catalysts. Commercial zeolite USY (CBV720), ZSM-5 (CBV2314), and beta (CP811C-300) catalysts are used to prepare their respective micro-mesoporous composite catalysts. Al-SBA-15 and various Al-SBA-16 catalysts are synthesized with increased acidic character. Some mesoporous composite catalysts with zeolite nano-seeds are also prepared. The catalysts are characterized by using SEM, TEM, XRD, EDX, N2-BET, FTIR, and py-FTIR techniques. The results of characterizations showed the desired form of the catalysts. In order to screen out some of the catalysts, hydrocracking experiments with the model plastic mixture are conducted in a high pressure autoclave reactor. Initial experiments are performed at initial cold hydrogen pressure of 20 bar, 60 min residence time, feed to catalyst ratio of 20:1 (by wt.), and at various levels of temperature (350‒425°C). The products of the reactions are analyzed for conversion and yields of gas, oil (n-heptane soluble portion of liquid), and liquid. The oil produced is further analyzed with GC-FID and FTIR analysis. On the basis of conversion and selectivity towards liquid enriched with gasoline, five best performing catalysts are chosen for additional experimentation. These catalysts are then tested with HDPE and actual waste plastic mixture. Stability of these five supports is evaluated by using spent catalysts and regenerated spent catalysts from a previous run. Two catalysts performed remarkably well in all these experiments. The two catalysts are the composite of zeolite ZSM-5 (ZC-FP) and the composite of zeolite beta (BC27). The five best catalysts are then impregnated with 0.5wt% of platinum to prepare their respective bifunctional catalysts. The performance of these five platinum impregnated catalysts is then evaluated by hydrocracking the model plastic mixture at three reaction temperatures (325°C, 350°C, and 375°C). It is found that after platinum impregnation all the catalysts produced higher conversion and higher gaseous yield than that of their corresponding catalysts without impregnation. The quality of oil obtained over these platinum catalysts is much better with higher amounts of alkanes, lower amounts of aromatics, and lower quantities of unsaturated compounds. Among these impregnated catalysts PtBC27 produced the highest liquid yield with increased gasoline content. This catalyst is then tested with actual waste plastic mixture at 60 min residence time, 20 bar initial cold hydrogen pressure, feed to catalyst ratio of 20:1 (by wt.), and reaction temperature of 375°C. It is observed that this catalyst delivered 90.1wt% conversion and 68.6wt% liquid yield with gasoline content of 65.8wt%. In parallel reactions, ZC-FP catalysts is impregnated with different combinations of metals and tested with model plastic mixture at 325°C, 350°C, and 375°C. It is found that CoRuZC-FP catalyst produced the highest liquid yield at 375°C. However, its oil contained lower quantity of gasoline than that obtained over PtZC-FP and PtPdZCFP catalysts. The ZC-FP catalyst is also used to investigate the effect of change in initial cold hydrogen pressure, catalyst amount, and residence time at different reaction temperatures. This data is then used to study the kinetics of the hydrocracking reaction. The regression of the experimental data is carried out and a simple kinetic model is developed where the activation energy for the hydrocracking reaction is found to be 236.8 kJ/mol. Finally, a commercial hydrocracking unit is conceptualized and a process flow diagram of the process is developed.