In this research work caffeine content in coffee bean samples from Daroo Labu, Booke, Shanan Dhugoo, Haabro and Xuloo of Western Hararghe administrative zone of Ethiopia were determined using High Performance Liquid Chromatography (HPLC) method. Caffeine in aqueous extract of coffee bean samples was dissolved in water (HPLC grade) to determine caffeine contents in coffee bean samples using HPLC method. The linearity of the High Performance Liquid Chromatography (HPLC) method obtained were R2 = 0. 9998. Limits of detection (LOD) and limit of quantification (LOQ) obtained were 9.10 ppm and 27.54 ppm respectively. The caffeine concentration in coffee bean samples obtained using HPLC method was 58.7065 ppm or 1.46% (w/w), 57.7152 ppm or 1.44% (w/w), 58.23408 ppm or 1.45% (w/w), 57.59039 ppm or 1.43% (w/w), 47.79959 ppm or 1.19% (w/w) for Booke, Shanan Dhugoo, Haabro, Daroo Labu and Xuloo coffee bean samples respectively. There is no significant difference between the caffeine contents of all coffee bean samples.

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Carbon dioxide produced by means of human matters to do is one of the essential contributions accountable for the greenhouse effect, which is enhancing the Earth's climate. From the viewpoint of green chemistry and sustainable development, it is of exquisite magnitude to synthesize chemical substances from CO 2 as C1 source with the aid of C-N bond formation. Therefore, post-combustion CO 2 catch and its conversion into excessive value-added chemical substances are crucial components of today's inexperienced industry. Chemical fixation of carbon dioxide (CO 2 ), which is much less highpriced and renewable carbon source, is turning into greater and greater important. The improvement of each new reactions and new catalysts is wished to overcome the kinetic and thermodynamic balance of CO 2 . Organic and steel catalysts with unique and high-quality endeavor and selectivity have been developed for a wide variety chemical conversions of CO 2 . On the different hand, carbon dioxide is a ubiquitous, cheap, abundant, non-toxic, non-flammable and renewable C1 source. Among CO 2 usages, this evaluate pursuits to summarize and discuss the advances in the response of CO 2 , in the synthesis of cyclic carbonates, carbamates, and urea.