Polyisobutene preparation

The high proportion of unsaturated terminal groups found in polyisobutenes prepared in solution at low temperature [18] makes it appear likely that a similar process operates there, although the reaction (V) above might also account for at least some of these under certain conditions. 

Pathmamanoharan C and Philipse A P 1998 Preparation and properties of monodisperse magnetic cobalt colloids grafted with polyisobutene J. Colloid Interface Sol. 205 304-53... 

The nature and proportions of different kinds of end-groups in polyisobutenes depend upon the catalytic system and the solvent used in their preparation. 

H.P. Rath, H. Hoffmann, P. Reuter, and H. Mach, Preparation of polyisobutene, US Patent 5 191 044, assigned to BASF Aktiengesellschaft (Ludwigshafen, DE), March 2,1993. 

The time-conversion curves do not pass through the origin in spite of all precautions taken, there was always a small dark reaction. This dark reaction is obviously caused by traces of light penetrating into the ampule during the preparation and is not caused by a thermal reaction. The conversion of the dark reaction in experimental times is always so small that it does not have any implications for the size of the radiation-induced reaction. Irradiation of a solution of polyisobutene in carbon tetrachloride in the absence of chlorine showed that only negligible amounts of chlorine (about 2 weight %) were taken up from the solvent. 

It should be recalled that various other two-step macromonomer synthesis have been developed using the inifer technique as an adequate functionalization method for preparing the precursor. Thus, starting from to-chloro-polyisobutene, the de-hydrohalogenation can be followed by hydroboration and selective oxidation to yield almost quantitatively the -hydroxy precursor 78) ... 

Harrison [4] prepared poly(isobutylene-g-succinic anhydride) by reacting a 1 1 mole ratio of polyisobutene/maleic anhydride using di-t-butylperoxide as catalyst where the ratio of di-t-butylperoxide/polyisobutene was 0.05 1, respectively. In this procedure polyisobutylene had a Mn of roughly 2300 daltons while the product had a SAP number of 26.2 mg for the KOH/g sample. Poly (isobutylene-g-succinic anhydride) has also been prepared in the simultaneous chlorination/maleation process described by Barini [5]. 

Considerable efforts have been directed, primarily in Kennedy s group [3], to synthesize a series of block copolymers of isobutene with isoprene [90,91], styrene derivatives [92-104], and vinyl ethers [105-107]. Figure 7 lists the monomers that have been used for the block copolymerizations with isobutene. The reported examples include not only AB- but also ABA- and triarmed block copolymers, depending on the functionality of the initiators (see Chapter 4, Section V.B, Table 3). Obviously, the copolymers with styrene derivatives, particularly ABA versions, are mostly intended to combine the rubbery polyisobutene-centered segments with glassy styrenic side segments in attempts to prepare novel thermoplastic elastomers. These styrene monomers are styrene, p-methylstyrene, p-chlorostyrene, a-methylstyrene, and indene. 

In a reversed way, cationically prepared end-functional polymers are used to quench other living polymers. For example, living anionic polystyrene may be terminated by polyisobutenes with silylchloride terminals [119,120] or epoxide ends [121,122] and by poly(vinyl ethers) with acetal terminals [123], The former case is reported to give H-shaped, tetraarmed block copolymers. 

Rather interestingly, most of the end-functionalized polyisobutenes have been prepared by the inifer method, in sharp contrast to that those... 

Apart from the syntheses by living cationic polymerizations, a variety of polyisobutene macromonomers have been prepared by converting the chloride terminal derived from the inifer method (Section IV.A.3) [166-170] and more recently from living cationic polymerization... 

Polyisobutenes are prepared from pure monomer (>99.5%). Depending on polymerization temperature and solvent, polymers with a wide variety of molar masses can be obtained as the feed is cleared from n-butenes which leads to transfer and/or termination. Polyisobutenes are typically classified in three categories ... 

The first (partly) successful attempts to prepare block copolymers by double cationic initiation involved the preparation of the first block, its isolation and transformation into a macroinitiator and the subsequent blocking with the second monomer. Thus, Jolivet and Peyrot reported in 1973 the synthesis of a poly(isobutene7>-styrene) based on the preparation of a terminally benzylated polyisobutene, the chloromethyla-tion of the aromatic end groups and the polymerisation of styrene onto these —CHjCl moieties catalysed by diethylahiminium chloride. The yield of block copolymer was limited due to transfer reactions in both the first and the second polymerisation, i.e. appreciable amounts of homopolymers were also obtained. A similar procedure was used by Kermedy and Melby a few years later to prepare the same type of copolymer. 

Name Polyisobutene Sample preparation Solid film, sodium chloride disk... 

Copolymerization initiated by A proceeds readily at low temperatures and gives isobutene—isoprene copolymers structurally identical to those prepared commercially utilizing a conventional Lewis-acid initiator. That is to say, there is no incorporation of isoprene in a 1,2- or 3,4-fashion, as would be anticipated at least in part for a Ziegler—Natta process. As with polyisobutene, lower temperatures result in higher molecular weights (polydispersities 2) while materials with high M values and a low polydisper-sity index could be obtained only at very low contents of isoprene. consistent with observations that chain-transfer processes are extremely facile following isoprene incorporation. - ... 

Other polymerization processes. Polyisobutene, traditionally prepared by the Cosden process, is a valuable lubricant, and also a route to higher value-added materials. In general it was observed that the catalytic activity of the ionic liquids increases towards higher degrees of polymerization from short-chain ohgomers as the alkylchain length of the l-alkyl-3-methylimidazohum or N-alkylpyridinium cation is increased. ... 

In this case the analytical band is at 10.52 pm, and for band ratio the 4.95 pm band is again used as the reference. Five standard blends with polyisobutene contents from 0 to 20% were prepared, with a nominal film thickness of 0.40 mm. When the measured film thickness was used the results were similar for height, area, and first derivative, with error indices around 2.5%. The smallest errors were found for area measurements using a 20 cm" slice around the peak maximum. 

Isobutene has the distinction of having been the first alkene to have been polymerized to a high molecular weight polymer whilst the polymer was the first polyalkene to have been commercially developed. Whereas polyethylene was first prepared (unexpectedly) in 1933 with pilot plant production not commencing until the 1st September 1939, and polypropylene not discovered until the early 1950s, the IG Farben company were as early as 1932 disclosing details of polyisobutene manufacture to the Standard Oil Co under a research agreement. 

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