Evaluation of the Na-EDTMP/borax system as a non-dispersing, high temperature retarder for oil well cement.

For well cementing at temperatures above 120 °C, thermal thinning depicts a major problem, promoting particle sedimentation decreasing slurry viscosities. This is partly caused by dispersing properties of common high temperature retarder systems and can lead to imperfect zonal isolation, endangering the stability of the wellbore. Counteracting additives tend to start losing their effectiveness at temperatures >140 °C.

Scrutinizing ligand exchange reactions in the formation of the precious group metal-organic framework Ru-HKUST-1: the impact of diruthenium tetracarboxylate precursor and modulator choice.

The precious group metal (PGM) analogues of the iconic metal-organic framework [Cu3(BTC)2] (HKUST-1; BTC = 1,3,5 benzenetricarboxylate) still represent a synthetic challenge, especially if targeting the univalent and ideally defect-free RuII,II variant. Herein we present a systematic study employing the controlled secondary building unit approach (CSA) by using a variety of diruthenium tetracarboxylate complexes [Ru2(RCO2)4] as precursors in the synthesis of univalent Ru-HKUST-1 samples. Carboxylate ligand exchange test reactions suggest the importance of a pKa match between precursor ligand and BTC linker.