Abstract: A process for the preparation of a compound of general formula ##STR1## in which R.sup.1 represents a hydrogen atom or a methyl group, one of R.sup.2 and R.sup.3 represents a hydrogen atom and the other of R.sup.2 and R.sup.3 is the same as R.sup.1, which comprises reacting a compound of the general formulaR.sup.1 CH.dbd.C.dbd.CH.sub.2 (II)with a salt of formic acid in the presence of a catalyst system comprising a palladium salt and a phosphorus compound of general formulaP(OX).sub.n (X).sub.3-n (III)in which n is 0,1,2 or 3 and each X independently represents an alkyl, alkenyl, aryl, aralkyl, alkaryl or cycloalkyl group, and recovering the desired compound of formula (I).

Abstract: A process for preparing spherical particles of a compound with the general formula Mg(OR).sub.2-a (OR').sub.a is disclosed. In the process R is an alkyl group with from 2 to 8 carbon atoms, R' is an alkyl group with from 1 to 7 carbon atoms and a is a number of from 0 to 0.5. The process comprises preparing a homogeneous solution of a compound Mg(OR).sub.2 in an aliphatic alcohol with the general formula R'OH, spray-drying the solution at a temperature of from 15.degree. to 85.degree. C., suspending the spray-dried solid particles in an aliphatic alcohol with the formula ROH in which R is the same alkyl group as present in the said compound Mg(OR).sub.2, heating the suspension in order to remove an alcohol with the formula R'OH from the liquid phase by distillation and separating the solid particles from the liquid phase.

Abstract: A process for the preparation of an olefin polymerization catalyst component which comprises contacting a solid composition obtained by combining a magnesium halide, an electron donor and a tetravalent titanium compound, this composition being substantially free from aluminum compounds, with a liquid medium comprising a halide of B, Al, Ga, In, Tl, Sn or Sb, these elements being present in their highest valency state or a halide of tetravalent Te, and removing from the catalyst component substantially all metal halide originating from the liquid medium as by washing the catalyst component with a hydrocarbon or halohydrocarbon liquid.

Abstract: A process for the preparation of an olefin polymerization catalyst component which comprises contacting a solid composition obtained by combining a magnesium halide, an electron donor and a tetravalent titanium compound, this composition being substantially free from aluminum compounds, with a liquid medium comprising a halide of B, Al, Ga, In, Tl, Sn or Sb, these elements being present in their highest valency state or a halide of tetravalent Te, and removing from the catalyst component substantially all metal halide originating from the liquid medium as by washing the catalyst component with a hydrocarbon or halohydrocarbon liquid.