Abstract: The process for preparing alkynediols of the formula (I) R1R2C(OH)—C≡C—C(OH)R1R2  (I) where R1, R2 are each independently H, or a C1-20-hydrocarbon radical which may be substituted by one or more C1-6-alkyls and/or be interrupted by nonadjacent heteroatoms and/or contain C—C double or triple bonds, by reacting compounds of the formula (II) R1—C(═O)—R2  (II) with acetylene in a polar aprotic solvent is carried out in the presence of basic alkali metal salts as catalysts.

Abstract: A self-regulating heater comprising a housing having a chamber therein and a heating element in the chamber. The heating element is a self-heating, positive temperature coefficient (PTC) resistor having low initial resistance which increases abruptly as its temperature rises above a given level. It has first and second substantially parallel surfaces spaced from one another, these surfaces each having a layer of electrically conductive material applied thereto for forming an ohmic contact surface. The heater further comprises a heat sink plate of thermally and electrically conductive material, the plate being positioned within the housing chamber so that one face of the plate is in heat-transfer relation with a first inside surface of the housing and so that the other side of the plate is in electrical contact and in heat transfer relationship with the first surface of the element.