Calcium Carbide: A Unique Reagent for Organic Synthesis and Nanotechnology

Abstract

Acetylene, HC≡CH, is one of the primary building blocks in synthetic organic and industrial chemistry. Several highly valuable processes have been developed based on this simplest alkyne and the development of acetylene chemistry has had a paramount impact on chemical science over the last few decades. However, in spite of numerous useful possible reactions, the application of gaseous acetylene in everyday research practice is rather limited. Moreover, the practical implementation of high-pressure acetylene chemistry can be very challenging, owing to the risk of explosion and the requirement for complex equipment; special safety precautions need to be taken to store and handle acetylene under high pressure, which limit its routine use in a standard laboratory setup. Amazingly, recent studies have revealed that calcium carbide, CaC2 , can be used as an easy-to-handle and efficient source of acetylene for in situ chemical transformations. Thus, calcium carbide is a stable and inexpensive acetylene precursor that is available on the ton scale and it can be handled with standard laboratory equipment. The application of calcium carbide in organic synthesis will bring a new dimension to the powerful acetylene chemistry.

Mechanochemie gasförmiger Reaktanten

“…[81] Diese Strategie ließ sich kürzlich fürd ie Erzeugung und den Gebrauch von HCN durch Kugelmahlen verwenden. [84,85] Die Vorteile des Gebrauchs von CaC 2 durch Mechanochemie gehen jedoch weit über die Überwindung von Unlçslichkeitsbarrieren und die Vermeidung des direkten Einsatzes von hochentzündlichem gasfçrmigem Acetylen hinaus.K ürzlich ermçglichte die mechanische Aktivierung von Calciumcarbid in einer Kupfer(I)-katalysierten Aldehyd/Alkine/Amin-Kupplung die Synthese von 1,4-Diamino-2-butinen, die anstelle der klassischen Propargylamin-artigen Produkte gebildet wurden. [82] Alle hier vorgestellten Beispiele zeigen die Kompatibilität von Kugelmahltechniken mit chemischen Umwandlungen, in denen Reaktanten in der Gasphase beteiligt sind.…”

Calcium‐Based Sustainable Chemical Technologies for Total Carbon Recycling

“…However, gaseous acetylene is explosive, even if mixed with other gases, and the corresponding laboratory practice is significantly retarded by this circumstance . Recent studies have shown how to develop convenient and practical procedures for acetylene chemistry with the involvement of calcium carbide . CaC 2 has a number of advantages over gaseous acetylene.…”

Using Calcium Carbide as an Acetylene Source for Cascade Synthesis of Pyrrolo[2,3‐b]quinoxalines via Copper‐Free Sonogashira Coupling Reaction

“…Calcium carbide has a number of advantages over acetylene gas. Neither oil nor natural gas is required to synthesize calcium carbide, its transportation does not have the same risks as for acetylene, there is no need to use complicated high‐pressure equipment, and working with calcium carbide is safer and more convenient . Furthermore, the use of calcium carbide in organic synthesis is more cost‐efficient and safer than the use of acetylene gas.…”