CS203519B1 - Trifunctional organo-lithium initiator and method for preparing the same - Google Patents

Description

CZECHOSLOVAK SOCIALIST REPUBLIC DESCRIPTION ^ 203519 (19) CERTIFICATE OF CERTIFICATE (11) (Bl) (51) Int. Cl.3 C 07 F 1/02 C 08 F 4/48 (22) Registered 30 10 78 (21) (PV 7030-78) (40) Published 30 08 80 OFFICE AND DISCOVERY (45) Published 15 01 83 (75) Author KAŠPAR MIROSLAV CSc., STĚTÍ and TREKOVAL JIŘÍ ing. CSc., PRAGUE (54) Trifunctional organ olithium initiator and method of its preparation 1

The invention relates to a trifunctional initiator for the anionic polymerization of diene astyrene monomers and to a process for its preparation.

The anionic polymerization of the diene and styrene polymeric star-type polymers is very broad and promising for the preparation of specifically crosslinked copolymers, block copolymers and crosslink condensation products, the so-called liquid rubber. This use is due to the possibility of terminating individual polymeric star chains with reactive functional groups. Nowadays, in practice, polymers prepared with alkyldilith initiators starting with two functional groups are used, but their copolymerization only produces a linear polymer. Cross-linking methods with multifunctional monomers such as divinylbenzene are known, but in this way, it is not possible to prepare defined networks, the crosslinking sites being determined statistically.

The introduction of a third lithium atom into the bi-functional initiator molecule encounters considerable difficulties due to the low reactivity of the respective tri-halogenoderivatives. The HC / (CH 2) nX / 3 species, where X is halogen for n = 1-3 react reluctantly with Wieia Yalroi, turning products of the Wurtz reaction. The preparation with n> 3 is uneconomical. Therefore, other methods of synthesis were sought for 203519 2 and it was found that the lithium metal was well adhered to the stilbene-type hyperbinding. SUMMARY OF THE INVENTION The present invention provides an initiator for anionic coordination polymerization of diene and styrene-type monomers containing three lithium atoms bonded to carbon atoms of the formula

The present invention relates to a process for the preparation of this initiator, characterized in that p-bromostilbene is reacted with metal lithium. The reaction according to the present invention proceeds according to the equation

If

Br - CeHCH = CHCeHs - -> Li - CsHd - CH (Li) - CH (Li) - CsHs

The course of the reaction is relatively smooth, and the yield in diethyl ether at room temperature approaches the theory. Mixtures with diethyl ether can also be used as medium as the medium. When using pure benzene, the reaction time is not prolonged. Upon dissolution of the product with water, a very pure diphenylethane was isolated, in which NMR containing no double admixture was found.

Claims (2)

Binding, thereby unambiguously confirming the progress of the reaction. Furthermore, the predicted high reactivity of all three lithium atoms in reaction with styrene and isoprene NMR was confirmed by studying oligomers. p-Bromstil-ben was prepared by adding p-bromophenylmagnesium bromide to phenylacetaldehyde: Br-C6H4-MgBr + C 6 H 5 -CH 2 -CHO-Br-C 6 H 4 -CH = CH-CsH 5 The primary secondary alcohol is potentially unstable and in acidic medium is readily dehydrated. It is therefore necessary to acidify the reaction mixture before isolating the product. EXAMPLES All reactions were carried out in an atmosphere of pure argon or nitrogen. 1. Place 2.5 g of magnesium shavings in 150 ml of saline diethyl ether in a 1 liter flask equipped with an intensive stirrer and a powerful reflux condenser. 25 g of p-dibromobenzene OBU is added dropwise with vigorous stirring 1. Trifunctional organolithium formula I formula I Li-C6H4-CH (Li-CH (Li-C6H5 (I) in 150 ml of ether) After stirring for about 1 hour, 10 g of phenylacetaldehyde in 100 ml are slowly added. The mixture was stirred for about 30 minutes, then the mixture was quenched with 100 mL of ice water and then 100 mL of 20% hydrochloric acid under vigorous stirring. The crude product is purified by multiple crystallization from benzene and the yellow crystals obtained are vacuum dried at 40 ° C. Melting point 107-108 ° C. The yield is about 11 g. 2. 2.6 .mu.-Bromostilbene in 20 ml of abs. Diethyl ether was added dropwise to 1 g of lithium suspension in 30 ml of diethyl ether at 20 DEG C. for 30 minutes, and the mixture was stirred for 10 hours. CO2 and O2 are better pr The bromide is removed by centrifugation, the remaining lithium by filtration on a glass frit under arginine. The initiator solution obtained has a concentration of about 0.19 M, i.e. 0.57 normality. YES 2. A process for preparing a trifunctional organo-lithium initiator of formula (I) according to claim 1, characterized in that the β-bromostilbene is reacted with lithium metal. Severografia, n. P., Plant 7, Most