Suzuki-Miyaura Cross-Coupling Reaction Based on Novel Palladium(II) Diphenylphosphine Derivative Catalyst

The synthesis and characterization of palladium complexes ((CH3)3SiC6H4PPh2)2PdCl2,4a, and ((CH3)3SiC12H8PPh2)2PdCl2, 4b, containing phosphine (CH3)3SiC6H4PPh2, 3a and (CH3)3SiC12H8PPh2,  3b ligands are reported. The phosphine ligands are prepared conveniently in high yield by treatment of the corresponding 1,4-dibromoarene  with one equivalent of butyl lithium, and one equivalent of ClPPh2 at -78 °C under an atmosphere of argon. The palladium complexes are synthesized by the reaction of Pd(cod)Cl2 with two equivalent of the above mentioned phosphine ligands. The new complexes were fully characterized by spectroscopic methods  and elemental analysis. Furthermore, the use of the palladium (II) complexes of such system as pre-catalysts for the Suzuki-Miyaura coupling of some arylbromides and arylchloride with substituted  phenyl boronic acid has been tested. Keywords:1,4-dibromoarene, Palladium complex, Suzuki coupling, catalyst

Benchmarking the scientific output of industrial wastewater research in Arab world by utilizing bibliometric techniques

Rapid population growth, worsening of the climate, and severity of freshwater scarcity are global challenges. In Arab world countries, where water resources are becoming increasingly scarce, the recycling of industrial wastewater could improve the efficiency of freshwater use. The benchmarking of scientific output of industrial wastewater research in the Arab world is an initiative that could support in shaping up and improving future research activities. This study assesses the scientific output of industrial wastewater research in the Arab world. A total of 2032 documents related to industrial wastewater were retrieved from 152 journals indexed in the Scopus databases; this represents 3.6 % of the global research output. The h-index of the retrieved documents was 70. The total number of citations, at the time of data analysis, was 34,296 with an average citation of 16.88 per document. Egypt, with a total publications of 655 (32.2 %), was ranked the first among the Arab countries followed by Saudi Arabia 300 (14.7 %) and Tunisia 297 (14.6 %). Egypt also had the highest h-index, assumed with Saudi Arabia, the first place in collaboration with other countries. Seven hundred fifteen (35.2 %) documents with 66 countries in Arab/non-Arab country collaborations were identified. Arab researchers collaborated mostly with researchers from France 239 (11.7 %), followed by the USA 127 (6.2 %). The top active journal was Desalination 126 (6.2 %), and the most productive institution was the National Research Center, Egypt 169 (8.3 %), followed by the King Abdul-Aziz University, Saudi Arabia 75 (3.7 %). Environmental Science was the most prevalent field of interest 930 (45.8 %). Despite the promising indicators, there is a need to close the gap in research between the Arab world and the other nations. Optimizing the investments and developing regional experiences are key factors to promote the scientific research

Solid-State Mechanochemical Synthesis of Kaolinite-Urea Complexes for Application as Slow Release Fertilizer

This study investigated a mechanochemical (MC) process for synthesizing a slow-release urea fertilizer by cogrinding the starting materials of (NH2)2CO and amorphous kaolinite in a planetary ball mill. The tests with kaolinite contents ranging from 25 to 75 wt. %, milling time ranging from 1 (h) to 3 (h) and mill rotational speeds from 200 to 700 rpm were performed to evaluate the incorporation of (NH2)2CO and release of nitrogen into the solution. The analyses conducted using XRD, TGA, FT-IR and KNDU (Kjeldahl Nitrogen Determination Unit) indicated that the MC process was successfully applied to incorporate (NH2)2CO into the amorphous kaolinite structure. The release of nitrogen from the system (kaolinite-(NH2)2CO) when dispersed in water for 24 h reached up to 20% at 25% wt of kaolinite. Moreover, under the milling speed conditions for the system (kaolinite–(NH2)2CO), release of nitrogen reached between 25 and 40%. These results indicated that the MC process can be developed to allow amorphous kaolinite to act as a carrier of nitrogen nutrients to be released slowly for use as fertilizer