Divinylbenzene addition reaction

PROPERTIES OF SPECIAL INTEREST BMI resins are generally brittle. They can be toughened with additives such aromatic diamines (chain extension via Michael Addition reaction), divinylbenzene or bis (ally Iphenyl) compounds (chain extension via Diels-Alder reaction and ene reaction, respectively), benzocyclobutene derivatives (chain extension via Diels-Alder reaction), low molecular weight rubber, and thermoplastics. Certain bismaleimides are liquid crystalline. ... 

The consecutive addition reactions of s-BuLi to 1,4-divinylbenzene according to equation 97 can be followed, after quenching with methanol, by GC, H NMR and MS of the products. The main product is the diadduct 376 however, a slow addition side reaction (equation 98) takes place between the monoadduct 375 and the diadduct, leading to the... 

The same kind of addition reaction as described in Section IV 1) and 2) can be performed with substituted bisacryl amides such as bisacryloylpiperidide and N,N -dimethylethylenediamine. However, the difference in the reactivity between the two acrylic double bonds is much less pronounced than in the case of p-divinylbenzene, so that a mere polycondensation occurs. Upon using a calculated excess of 1,4-bis-acryloylpiperidine bifunctional macromonomers of a known average molecular weight have been obtained by Ferruti et al. 90) ... 

At this stage, the self-condensation of the p-divinylbenzene-N,N -ethylenediamine monoadduct 83-84) should be mentioned again as the only type of self-condensation leading directly to a macromonomer without any additional reaction the final species always carries an unsaturation at one chain end. 

The preparation and use of two new experimental resins was described by Morris and Fritz [16]. Both resins were prepared by simple Friedel-Crafts addition reactions. One has the carboxyl group attached to the benzene ring of a spherical polystyrene-divinylbenzene (PS-DVB) resin via a spacer arm of three carbon atoms. The carboxyl group is attached directly to the benzene ring in the other resin. Excellent ion chromatographic separations of metal ions are possible using these resins in conjunction with any of several complexing eluents. 

Lithium dialkylamide having bulky alkyl groups, such as isopropyl groups, exhibits unique behavior in polymerization reactions of isoprene and divinylbenzene. It was previously reported by us that lithium dialkylamide underwent a stereospecific addition reaction with butadiene in the presence of an appropriate amount of dialkylamine in cyclohexane as solvent (1, 2). For instance, on reacting with butadiene, lithium diethylamide gave the sole adduct, 1-diethylamino-cis-butene-2, in a 98-997o purity. In the absence of free amine, on the other hand, no reaction took place under the same experimental conditions (50°C... 

As the writer reported previously, lithium diethylamide, in the presence of diethylamine, underwent the one to one addition reaction with styrene (5) or divinylbenzene (DVB) (6). No reaction, however, took place between lithium diisopropylamide and styrene. A surprising result, in contrast, was obtained in... 

Radial or star-shaped SBS triblock polymers have been prepared by the addition of divinylbenzene (30) in a coupling reaction with silicon tetrachloride (31) or with epoxldlzed polybutadiene or epoxidlzed soybean oil (32). 

The addition of maleic anhydride resulted in a fourfold increase in reaction speed (1), while the addition of divinylbenzene caused a viscosity rise of a factor 50 at relevant shear rates (10 s ) (11). Both additions had a stabilizing effect. This stabilization is further illustrated in Figs. 13.13 and 13.14. Both the addition of maleic anhydride and of divinylbenzene increased the maximum stable throughput at a high conversion level substantially. 

Polymer-bound z-nitrostyrenes on the basis of polystyrene/divinylbenzene and of polyfoxyethylene) represent polymer products usefril for addition reactions with the thiol groups of cysteine peptides or any other thiols in aqueous media. Thus, cysteine peptides can be removed selectively by revm ible addition from peptides mixtures. 

A typical system is a chlorome thy late d polystyrene resin cross-linked with 2 or 4% p-divinylbenzene and different amounts of chloromethylated sites (0.7—3.7 mequiv. of Cl per g of polymer) . The reaction is shown schematically in Eq. (6.19) and additional information may be found in Sects. 8.3 and 8.8. 

Polymeric particles can be constructed from a number of different monomers or copolymer combinations. Some of the more common ones include polystyrene (traditional latex particles), poly(styrene/divinylbenzene) copolymers, poly(styrene/acrylate) copolymers, polymethylmethacrylate (PMMA), poly(hydroxyethyl methacrylate) (pHEMA), poly(vinyltoluene), poly(styrene/butadiene) copolymers, and poly(styrene/vinyltoluene) copolymers. In addition, by mixing into the polymerization reaction combinations of functional monomers, one can create reactive or functional groups on the particle surface for subsequent coupling to affinity ligands. One example of this is a poly(styrene/acrylate) copolymer particle, which creates carboxylate groups within the polymer structure, the number of which is dependent on the ratio of monomers used in the polymerization process. 

The maleimide group can undergo a variety of chemical reactions. The reactivity of the double bond is a consequence of the electron withdrawing nature of the two adjacent carbonyl groups which create a very electron-deficient double bond, and therefore is susceptible to homo- and copolymerizations. Such polymerizations may be induced by free radicals or anions. Nucleophiles such as primary and secondary amines, phenates, thiophenates, carboxylates, etc. may react via the classical Michael addition mechanism. The maleimide group furthermore is a very reactive dienophile and can therefore be employed in a variety of Diels Alder reactions. Bisdienes such as divinylbenzene, bis(vinylbenzyl) compounds, bis(propenylphenoxy) compounds and bis(benzocyclobutenes) are very attractive Diels Alder comonomers and therefore some are used as constituents for BMI resin formulations. An important chemical reaction of the maleimide group is the ENE reaction with allylphenyl compounds. The most attractive comonomer of this family is DABA particularly when tough bismaleimide resins are desired. 

A naphthalene supported polymer was prepared by radical copolymerization of 2-vinylnaphthalene, styrene, and divinylbenzene.70 This catalyst was used to mediate metallation of alkyl chlorides by lithium. The reaction was done in the presence of electrophiles to afford, after quenching, the desired addition products. 

A very interesting technique that has been used widely in the MTO-catalyzed olefin oxidation reaction is the microencapsulation technique. This technique uses poly(4-vinylpyridine) (PVP), either 2% or 25% cross-linked with divinylbenzene (PVP-2% or PVP-25%, Fig. 4), as well as poly(4-vinylpyridine-/V-oxide) (PVPN-2%, Fig. 4). In addition, 2% cross-linked PS (PS-2%, Fig. 4, X = CH2) and a mixture of PS-2% and PVP-2% (5 1, Fig. 4, X = N) have been used as support polymers. This approach is based on the physical envelopment of the Lewis-acidic MTO by the PS polymer, enhanced by interactions of the 7t-electrons of the phenyl rings with MTO. In the case of the pyridine-containing polymers, Lewis acid-Lewis base interactions between the pyridine moiety and MTO obviously play an important role. In the case of the PVP and PVPN polymers, MTO can be incorporated in the support matrix by mixing the polymer and MTO in ethanol to obtain the desired immobilized catalyst. 

When applied to p-divinylbenzene (DVB), this reaction exhibits an interesting feature 81) a monoadduct is easily obtained and isolated because of the rather large difference in the reactivity between the two double bonds of p-DVB. However, when the reaction time is increased, the second DVB double bond may also be involved in the addition. The rate of the first step is roughly 20 times faster than that of the second ... 

---