Sodium bisulphate

The chemicals such as zinc acetate, sodium hydroxide, titanium isopropoxide, isopropyl alcohol, were products of BDH, CDH (India), and Fisher (UK). All the solvents, including ethanol (99%), chloroform (99%), and methanol (99.99%), were from Blulax, India. Glacial acetic acid, potassium iodide, sodium bisulphate, hydrochloric acid (98%), ammonium chloride, ammonium hydroxide, Hanus solution, ferric chloride, sodium thioselphate, and potassium hydroxide were all from Sigma Aldrich UK. The chemicals and reagents used for this study were all of analytical grade. The functional group identification of WCO and BD were recorded using Infrared, Spectrum FTIR (PerkinElmer) spectroscopy. The crystal structure of the synthesized catalyst materials were investigated using X-ray diffraction (Drawell XRD-700, UK) at Jimma University, Jimma, south western Ethiopia.

Anhydrous pyridine, 4-(N,N-dimethylamino)pyridine (DMPA), dichloromethane, sodium bisulphate, ε-caprolactone (ε-CL), stannous octoate SnOct₂ and polycaprolactone diol of nominal molecular weight of 522 g mol⁻¹ were supplied by Sigma Aldrich Química S.L. (Madrid, Spain) and used as received. 1,4-Butanediol (BD) was supplied by Sigma Aldrich Química S.L. and dried over magnesium sulphate, distilled and stored with nitrogen atmosphere before use. N,N-Dimethylacetamide (DMAc) was dried by distillation over commercial polymeric MDI.^{24 (link)} Amino-4-methylcoumarin (AMC) was provided by Carbosynth and used as received. Isophorone diisocyanate (IPDI) was a gift by Evonik Industries and used as received.