Calcium‐Based Sustainable Chemical Technologies for Total Carbon Recycling

Abstract

Calcium carbide, a stable solid compound composed of two atoms of carbon and one of calcium, has proven its effectiveness in chemical synthesis, due to the safety and convenience of handling the C≡C acetylenic units. The areas of CaC2 application are very diverse, and the development of calcium‐mediated approaches resolves several important challenges. This Review aims to discuss the laboratory chemistry of calcium carbide, and to go beyond its frontiers to organic synthesis, life sciences, materials and construction, carbon dioxide capturing, alloy manufacturing, and agriculture. The recyclability of calcium carbide and the availability of large‐scale industrial production facilities, as well as the future possibility of fossil‐resource‐independent manufacturing, position this compound as a key chemical platform for sustainable development. Easy regeneration and reuse of the carbide highlight calcium‐based sustainable chemical technologies as promising instruments for total carbon recycling.

Mechanosynthesis of Odd‐Numbered Tetraaryl[n]cumulenes

“…Previous attempts to use CaC 2 as as urrogate of acetylene in solution-based alkynylation reactions have afforded mostly propargyl alcohols such as 3a after the ethynylation of carbonylic compounds. [12] Initial experiments,m illing 1a and CaC 2 (1:2 ratio) for 3h at 800 rpm in aplanetary ball mill did not promote any chemical transformation, and only 1a was recovered after the workup of the reaction mixture.Then, aseries of additives were tested with aim of facilitating the activation of CaC 2 ,f or example, through am echanochemical salt metathesis reaction. [12] Initial experiments,m illing 1a and CaC 2 (1:2 ratio) for 3h at 800 rpm in aplanetary ball mill did not promote any chemical transformation, and only 1a was recovered after the workup of the reaction mixture.Then, aseries of additives were tested with aim of facilitating the activation of CaC 2 ,f or example, through am echanochemical salt metathesis reaction.…”

“…As starting point, we envisioned that amechanochemical activation of benzophenone (1a)a nd solid calcium carbide (CaC 2 ) [12] in the ball mill would enable the mechanosynthesis of propargylic diol 2athrough adouble alkynylation reaction. Previous attempts to use CaC 2 as as urrogate of acetylene in solution-based alkynylation reactions have afforded mostly propargyl alcohols such as 3a after the ethynylation of carbonylic compounds.…”

Bio‐Based Cycloalkanes: The Missing Link to High‐Performance Sustainable Jet Fuels

“…[280] Calcium carbide has also been used to produce isophorone via a mild conversion process. [281,282] As a substituted cyclohexane, isophorone provides several promising routes to cycloalkane fuels.…”

Understanding the solubilization of Ca acetylide with a new computational model for ionic pairs

“…[25][26][27] Moreover, CaC 2 is envisioned to become the feedstock for the sustainable, carbon-neutral chemical industry. 16,21,28 It is also considered valuable or promising in the synthesis of nanostructured materials, 29,30 agriculture, [31][32][33][34] and metallurgy (alloy making, see Section 2.3.8 in ref. 28 ).…”

“…16,21,28 It is also considered valuable or promising in the synthesis of nanostructured materials, 29,30 agriculture, [31][32][33][34] and metallurgy (alloy making, see Section 2.3.8 in ref. 28 ). However, CaC 2 is insoluble in organic solvents, which hampers its reactivity in the liquid phase.…”