Reduction of Water Waste in an Organic Chemistry Laboratory Using a Low-Cost Recirculation System for Condenser Apparatus

Abstract

A low-cost and easy-to-use water recirculation system for a condenser apparatus was designed and installed in an organic chemistry teaching laboratory. Relying on gravity and a small pump for water circulation, it supplies four stations simultaneously. The water recirculation system works very well with condensers used for distillation and reflux reactions, as well as with rotary evaporators. This innovative idea has led to an annual water savings of more than 14 400 L while running only 2 lab periods per week with up to 24 students per period. Its low cost and easy installation make it convenient and easily adoptable by any laboratory where the waste of water from condensers needs to be addressed, especially in places where water scarcity is already hindering such significant scientific activities.

Gravimetric and Thermal-Imaging Characterization of Water-Free Reflux Condensers for Laboratory Applications

“…Rather than using cooling water from a tap, a condenser can be connected to a recirculating chiller, 4 usually containing some mixture of water and ethylene glycol as the working fluid, or a closed-loop cooling water system. 5 Another design simply calls for filling the cavity of the condenser with a static fluid to act as a heat sink. 6,7 Although such alternative designs have advantages in reducing flood risk and improving water sustainability, they may have a trade-off in either condenser performance, ease, cost of use, and/or energy consumption.…”

“…To mitigate these issues, several creative alternatives to traditional once-through water-cooled condensers have been proposed. Rather than using cooling water from a tap, a condenser can be connected to a recirculating chiller, usually containing some mixture of water and ethylene glycol as the working fluid, or a closed-loop cooling water system . Another design simply calls for filling the cavity of the condenser with a static fluid to act as a heat sink. , …”

Transesterification of Isoamyl Acetate─An Experiment in Green Organic Chemistry

“…Products which are refined by students are often treated as waste. With the increasing awareness of energy conservation and environmental protection, many educators are applying the concept of green chemistry when teaching experimental classes by revising the design of experiments to reduce environmental pollution. − In the teaching experiment for the preparation of isoamyl acetate offered by the Chemical Experiment Center of Dalian University of Technology, at least 2 L of isoamyl acetate is disposed as waste every year. , Similarly, the methanol recovered in the liquid chromatography experiment is treated as waste liquid; the cost for disposal of these reagents is high. This paper reports a green chemistry experiment using recycled isoamyl acetate and methanol to generate isoamyl alcohol through a transesterification reaction catalyzed by KOH. − The isoamyl alcohol can be reused as the reaction raw material in the teaching experiment for the preparation of isoamyl acetate.…”

Project and Implementation of an Educational Large-Scale Water Distillation Unit with a Closed-Circuit Condenser

“…With these concerns in mind, several authors have tried to reduce water usage in laboratory practices. Schoeddert et al [7] designed a low-cost, easy to make recirculation system for a condenser apparatus, which allows for saving over 14.4 m 3 of cooling water per year. The system was designed for organic chemistry labs and relied on gravity and a small pump to circulate the cooling water between an upper and a lower reservoir Sustainability 2020, 12, 3239 2 of 12 while supplying four different workstations at the same time.…”

“…Currently, the most popular teaching method relies on classic lectures with a presentation of concepts and little to no involvement from the students. Despite this, active learning, where students are directly involved with the subject rather than being passive receptors, has been proven to help students retain concepts and information [7]. Well-designed laboratories for undergraduate engineering programs are essential to achieving pedagogical success.…”