Formaldehyde, single-step condensation

SINGLE-STEP CONDENSATION OF NAPHTHOLS AND BISPHENOLS WITH FORMALDEHYDE... 

As far as calix[4]pyrrole-based materials are concerned, particular emphasis should be placed on the production of chelating resins. Those obtained by the condensation reaction of calix[4]pyrrole and formaldehyde in the presence of formic acid offer potential for their use as extracting agents for fluoride removal from water. Their advantage relies on the fact that a single-step procedure is required for polymerisation. However, research in this area is in a preliminary stage. Much work needs to be done to establish the full capacity of these materials to take up fluoride from water, the kinetics of the process, and the optimum experimental conditions for fluoride extraction. Although, their ability to extract fluoride reaches a value of 88% from solutions of tetra-n-butylammonium fluoride... 

Although known as an explosive since 1894, PETN was used very little until after World War I when the ingredients to make the starting material became commercially available. The symmetrical, solid alcohol starting material, pentaerythritol, is made from acetaldehyde and formaldehyde, which react by aldol condensation under basic catalysis followed by a crossed Cannizzaro disproportionation to produce the alcohol and formate salt. Although the reaction takes place in a single mixture, it is shown below in two steps for clarity. 

This consists in causing formaldehyde to react with acetylene in the presence of a copper-based catalyst The ethynybtian reaction yields 1,4-butynediol and a few per cent of propargyl alcohol resulting from the condensation of a single molecule of formaldehyde. The 1,4-butynediol is hydrogenated to 1,4-butanediol in a second step. 

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