Abstract: A process is described for the preparation of compounds having the formula (I) C6F4HX, wherein X is Br or Cl, which comprises reacting tetrafluorobenzene with a halogen in the presence of a Lewis acid catalyst.

Abstract: A “bridged” bis-cyclopentadienyl complex which can be advantageously used for the formation of a catalytic system active in the (co)polymerization of ethylene and other &agr;-olefins is represented by means of the following formula (II): wherein: M represents a metal selected from titanium, zirconium or hafnium; A′ and A″ each independently represent an anion containing an &eegr;5-cyclopentadienyl ring coordinated to M; R′ or R″ each independently represents a group of an anionic nature &sgr;-bound to the metal M; B represents an unsaturated bivalent organic residue having from 1 to 30 carbon atoms, bound, respectively, to the ring of group A′ and to the —CH2-methylene group by means of carbon atoms.

Abstract: A “bridged” bis-cyclopentadienyl complex which can be advantageously used for the formation of a catalytic system active in the (co)polymerization of ethylene and other a-olefins is represented by means of the following formula (II): 1

Abstract: Diricinoleylphosphatidylcholine (I) in an optically active form is obtained with good yields and a high purity by means of a process which comprises: a) esterifying the terminal carboxylic group of ricinoleic acid (III) with an alcohol having from 1 to 4 carbon atoms to give the corresponding ester having formula (IV); b) protecting the hydroxylic group of the ester of ricinoleic acid (IV) with a protecting group removable under bland operating conditions and isolating the ester of ricinoleic acid of which the hydroxylic group (V) is protected; c) hydrolyzing the ester of ricinoleic acid of which the hydroxylic group (V) is protected and isolating the ricinoleic acid of which the hydroxylic group (VI) is protected; d) acylating L-&agr;-glycerophosphatidylcholine (II) with an imidazolic or triazolic derivative of the compound having formula (VI) and isolating the diricinoleylphosphatidylcholine of which the hydroxylic group (VII) is protected; e) removing the protecting group from the hydroxylic group of

Abstract: A “bridged” bis-cyclopentadienyl complex which can be advantageously used for the formation of a catalytic system active in the (co)polymerization of ethylene and other &agr;-olefins is represented by means of the following formula (II): wherein: M represents a metal selected from titanium, zirconium or hafnium; A′ and A″ each independently represent an anion containing an &eegr;5-cyclopentadienyl ring coordinated to M; R′ or R″ each independently represents a group of an anionic nature a-bound to the metal M; B represents an unsaturated bivalent organic residue having from 1 to 30 carbon atoms, bound, respectively, to the ring of group A′ and to the —CH2— methylene group by means of carbon atoms.

Abstract: Process for preparing elastomeric copolymers of ethylene-propylene (EPM) type and elastomeric terpolymers of ethylene-propylene-diene (EPDM) type with a propylene content comprised within the range of from 15 to 75%, carried out in the presence of metallocenes of formula (I) ##STR1##

Abstract: Catalytic component for the copolymerization of ethylene with alpha-olefins having general formula (I): ##STR1## wherein: A is a cyclopentadienyl derivative having general formula (II) ##STR2## B is selected from: 1) any of the cyclopentadienyl derivatives A defined above2) a monofunctional cyclopentadienyl radical (F) selected from cyclopentadienyl, indenyl, fluorenyl and the relative alkyl, aryl, trialkylsilyl substituted derivatives;Q, a bridge between A and B, is a bifunctional radical.

Abstract: A process is disclosed for preparing alkyl glycosides of general formula (I), by reacting an alcohol with a reducing sugar or with an equivalent of the latter, in the presence of a binary catalyst formed by a strong organic acid and a weak, also organic, base, having a K.sub.a within the range of from 10.sup.-8 to 10.sup.-1.

Abstract: A process is disclosed for producing particular hydroxyalkyl glucosides in the presence of a binary catalyst.

Abstract: Preparation of diethers of the formula ##STR1## wherein R is an alkyl, cycloalkyl, aryl, or aralkyl radical, by formation of an unsaturated aldehyde of the formula ##STR2## wherein R is as defined above, by means of an aldol condensation reaction, reduction of said aldehyde to form the corresponding saturated compound, transformation of the saturated compound into the corresponding diol, and consequent methylation of the diol into diether.

Abstract: Diethers of general formula: ##STR1## where R, R.sup.I, R.sup.II, R.sup.III, R.sup.IV and R.sup.V are the same or different and are H, C.sub.1-18 linear or branched alkyl, C.sub.5-18 cycloalkyl, C.sub.6.about. aryl, C.sub.7-18 alkylaryl or C.sub.7-18 arylalkyl radicals, provided that when R is alkyl, R.sup.I is other than H or alkyl and when R.sup.I is alkyl, R is other than H or alkyl; R.sup.VI and R.sup.VIII are the same or different and are C.sub.1-18 linear or branched alkyl, C.sub.5-18 cycloalkyl, C.sub.6-18 aryl, or C.sub.7-18 arylalkyl radicals; and two or more of R to R.sup.V may be bonded to form a cyclic structure having 5 to 18 carbon atoms.The diethers are particularly useful in the preparation of Ziegler-Natta catalysts.

Abstract: A process for preparing a compound of the formula (I) ##STR1## wherein R.sub.1 and R.sub.2 are individually selected from the group consisting of hydrogen and methyl or R.sub.1 and R.sub.2 together represent an ethylene bridge group comprising:reacting a diamine of the formula (II)H.sub.2 N--CHR.sub.1 --CHR.sub.2 --NH.sub.2 (II)where R.sub.1 and R.sub.2 are defined as above with formaldehyde and an alkaline metal cyanide at a pH in the range of about 0 to 2 to produce a tetranitrile of the formula (III):(NCCH.sub.2).sub.2 N--CHR.sub.1 --CHR.sub.2 --N(CH.sub.2 CN).sub.2(III)hydrating said tetranitrile to yield an acid addition salt of a tetraamide of the formula (IV):(H.sub.2 NOCCH.sub.2).sub.2 N--CHR.sub.1 --CHR.sub.2 --N(CH.sub.2 CONH.sub.2).sub.2 .2HX (IV)where R.sub.1 and R.sub.