摘要:
Ketones of the formula II ##STR1## with Ar, R.sup.1 and R.sup.2 as indicated below, can be hydroxylated, readily and in high yields, in the .alpha.-position using tetrahalogenomethanes and alkali metal hydroxides under phase-transfer conditions.
摘要:
Hydroxyalkylphenones of formula I ##STR1## wherein R is hydrogen, halogen, alkyl of 1 to 18 C atoms, alkoxy of 1 to 4 C atoms or ##STR2## R.sub.a is hydrogen, halogen or alkyl of 1 to 4 C atoms; R.sup.1 and R.sup.2 (a) are each alkyl of up to 14, together 4 to 16, C atoms or together are alkylene of 4 to 8 C atoms, if R is hydrogen, halogen, alkyl of 1 to 6 C atoms or alkoxy of 1 to 4 C atoms, or (b) are each alkyl of 1 to 6 C atoms or together are alkylene of 2 to 8 C atoms, if R is alkyl of 3 to 18 C atoms or ##STR3## R.sup.3 and R.sup.4 are each alkyl of 1 to 6 C atoms or together are alkylene of 2 to 8 C atoms and Z is --CO--, --CH.sub.2 --, --O-- or --S--; are suitable as initiators for radiation curing aqueous prepolymer dispersions. They have good stability in aqueous systems and also upon removal of the water from these systems, and they have a considerably increased reactivity in their ability to initiate the curing of aqueous systems curable by radiation.
摘要:
The stereospecific preparation of D(+)-biotin is improved by a synthetic route involving the conversion of 3,4-isopropylidene-D-arabinose in which the OH group in the 2-position is not protected, into an ester of 6,9-dihydroxy-7,8-isopropylidenedioxynona-2,4-dienoic acid, the latter then being catalytically hydrogenated and subsequently converted into D(+)-biotin in a manner known per se.
摘要:
Articles having a substrate coated with a oriented polymer having polar monomer units wherein the monomer units and main polymer chains originate from cyclic monomers polymerized by ring opening polymerization through impinging light on the coated surface.
摘要:
Polymer compositions exhibiting liquid-crystalline phases contain chemically bonded mesogenic groups of the formula Ia and/or Ib: ##STR1## in which Q.sup.1 is H, alkyl or alkoxy having 1-5 C atoms, F, Cl, Br or CN,X.sup.1 to X.sup.5 each, independently of one another, are H or an alkyl group having up to 15 C atoms, in which it is also possible for one or two non-adjacent CH.sub.2 groups to be replaced by a group from the group comprising --O--, --S--, --O--CO--O--, O--CO--NH--, --CO--, --CO--O--, --CO--S--, --S--CO--, --SO-- and --SO.sub.2 --.Process for the preparation of polymer compositions of this type comprises the polymerization or grafting of suitable monomers.Polymer compositions of this type are used as substrates in electronics for the fiber and foil techniques.