Abstract: (i) A method for emulsion polymerization of tetrafluoroethylene, which comprises emulsion-polymerizing tetrafluoroethylene in the presence of a polymerization initiator, a paraffin wax containing not larger than 100 ppm of a reducing substance and an emulsifier, and (ii) a method for preventing irregular polymerization of tetrafluoroethylene, which comprises using the above method for emulsion polymerization give a constant polymerization time, and polytetrafluoroethylene having values of physical properties which meet the desired standard requirements.

Abstract: There is provided a precisely quantitative measurement method of a hydrocarbonaceous polymerization inhibitor component in a fluorine-containing olefinic monomer, which inhibitor component is contained in the monomer in such a trace amount that it cannot be detected by a gas chromatography. In the method, an ultraviolet absorption spectrum of a concentrated sulfuric acid is measured after it is contacted with the fluorine-containing olefinic monomer and the concentration of the polymerization inhibitor is obtained based on an absorbance of the spectrum and a calibration curve which has been beforehand obtained.

Abstract: A process for purification of hydrochloric acid containing hydrogen fluoride, which process comprises steps of:contacting the hydrochloric acid containing hydrogen fluoride with at least one silicon compound of the formula:R.sup.1 R.sup.2 R.sup.3 SiX (1)wherein X is chlorine, hydroxyl or OSiR.sup.4 R.sup.5 R.sup.6, and R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are the same or different and alkyl groups having 1 to 4 of carbon atoms, andrecovering a trialkylfluorosilane compound produced in said contacting step of the formula:R.sup.1 R.sup.2 R.sup.3 SiF (2)wherein R.sup.1, R.sup.2 and R.sup.3 are the same as defined above,said recovering step comprising sub-steps of: hydrolyzing the produced trialkylfluorosilane compound (2) after the recovery thereof to convert to a trialkylsilanol compound of the formula:R.sup.1 R.sup.2 R.sup.3 SiOH (3)wherein R.sup.1, R.sup.2 and R.sup.