PROPENE TRIMER

Martens, ).A., Verrelst, W.H., Mathys, G.M., Brown, S.H., and Jacobs, P.A. (2005) Tailored catalytic propene trimerization over addic zeolites with mbular pores. Angew. Chem. Int. Ed.,... 

S. H., Jacobs, P. A., Tailored catalytic propene trimerization over acidic zeolites with tubular pores p. 5587-5590, Copyright Wiley-VCH Verlag GmbFI Co. KGaA (2005)... 

Accounting for a share of about 73 % of total production capacity, C4 products have firmly established their leading position in this field. Ethylene hydroformylation to propanal amounts to 2-3 % of the hydroformylation capacity for C4 products and is only of minor importance. The hydroformylation of olefins of medium chain length, predominantly in the Cg/Cg range (diisobutene, propene trimer), makes up around 20 % of the total production capacity. Only about 6 % of the total production capacity is used to hydroformylate higher olefins. 

PROPENE, TRIMER (139-01-4) Forms explosive mixture with air (flash point 75°F/24°C). Violent reaction with strong oxidizers, strong. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

Typically these compounds have their origin in alkenes possesssing a single double bond emanating from the petrochemical industry, such as propene, isobutene and their polymers, diisobutene and propene trimer. The uses of ethene to produce 4-ethylphenol and of propene to give 4-hydroxycumene are not reviewed here, reference having been made to the latter in the introductory chapter on the preparation of resorcinol and hydroquinone. 

In one approach propene trimer was added to a solution of boron trifluoride in phenol and the mixture was introduced into heptane. The BF3 evolved was absorbed in phenol for reuse (ref.3) and upon recovery of the heptane. 

Alkylphenol ethoxylates are important kinds of nonionic surfactants. A characteristic feature of the catalytic ethoxylation of alkylphenols is the enhanced reactivity of phenol hydroxyl for ethylene oxide in comparison with alcohols. Esters of ethylene glycol and alkylphenol behave already as an alcohol. Therefore di-, tri-, and m-mers are allowed to form only after the complete consumption of the starting material. All commercial ethoxylated alkylphenols are mixtures of oligomer-homologues having a Poisson-like distribution with some PEG and catalyst as impurities. Both alkylphenols and dialkylphenols are useful for ethoxylation as a hydrophobic moiety. Among the alkylphenols, isooctylphenol and isononylphenol are most widely used. They are synthesized by the Friedel-Crafts alkylation of phenol with butene dimer and mixture of propene trimers, respectively. 

The newly-formed carhocation either eliminates a proton and forms a dimer or attacks another propene molecule and eliminates a proton, giving the trimer. 

Further protonation of the trimer produces a C9 carhocation which may further react with another propene molecule and eventually produce propylene tetramer. 

The addition of one olefin molecule to a second and to a third, etc. to form a dimer, a trimer, etc. is termed oligomerization. The reaction is normally acid-catalyzed. When propene or butenes are used, the formed... 

Aldehyde dimers and trimers are common byproducts produced during the hydro formylation of propene. Union Carbide addressed the problem in a creative way when it was discovered that the dimers and trimers could be used as the principal reaction solvent for hydroformylation.[32] Elimination of an extraneous solvent simplified the process. The Ester-diol Trimers may equilibrate, as shown in Equation 2.9 to give a mixture of diol, a dimer, and the diester of the diol, which is a tetramer of butanal. 

Figure 13.33 Yield (Y) of propene dimers, trimers, tetramers and total true oligomers (di- to hexamers, without products with intermediate carbon numbers obtained by cracking and recombination of fragments)...

Figure 13.35 Skeletal distribution of trimer fractions at 30% propene conversion, obtained on collidine-treated ZSM-22 (TON), ZSM-23 (MTT), ZSM-22 (TON), ZSM-48...

Polymerization of propene at 330° in the presence of 90% ortho-phosphoric acid under about 100 atmospheres initial pressure yielded a product consisting of paraffinic, olefinic, cycloparaffinic and cycloolefinic, and aromatic hydrocarbons (Ipatieff and Pines, 70). About 8% of the product boiled in the dimer (C6) range and about 25% in the trimer (C9) range. Isobutane was formed to the extent of more than 2% by weight of the total polymer. 

Propene also undergoes conjunct polymerization in the presence of dilute phosphoric acid at high temperatures and pressures (Monroe and Gilliland, 58). When propene was treated with 10-30% phosphoric acid at 260-305° and at 170-410 atmospheres pressure, the only operating variable which appreciably affected the composition of the polymer was the extent to which the feed was polymerized. At constant percentage reaction of the feed under these conditions, the temperature, pressure, and acid catalyst concentration had no effect on the product composition. At low conversions, the polymer consisted of nearly pure dimer at 50% polymerization, two-thirds of the total was dimer and even when the feed was almost completely polymerized, the dimer fraction amounted to 35-40 % of the total polymer. The dimer and trimer fractions obtained at temperatures of 305° or lower using a acid concentrations below 30% contained about 25% paraffins and little or no naphthenes or aromatic hydrocarbons. 

The first-formed cation (42) can add to a second molecule of 2-methyl-propene (41) to yield the new (dimeric) cation (43) this in turn can lose a proton to yield the Cg alkene (44) or, alternatively, add to a third molecule of alkene to yield the (trimeric) cation (45), and so on. 

In the presence of hydrogen, for example, optically active saturated trimers of propene were obtained, albeit in low yields, by using (EBTHI)ZrCl2 (1) [10] and methylalumoxane [ 11 ]. At low relative concentrations of alkenes, their oligomers, mainly dimers through pentamers, were... 

A catalyst based on the mesoporous molecular sieve MCM-41 aluminosilicate has been used for the oligomerization of propene and butenes[51-53] at low temperatures (between 353 and 473 K). The catalyst shows higher activity and selectivity for the formation of trimers and tetramers as compared with HZSM-5 and HZSM-23. 

Table 11. Comparison of the temperature dependence of the enantiomeric excess (calculated from mmmm 0.2) obtained in bulk polymerization of propene to the ee observed in the trimer fraction produced at [propene] - 0 by (S)-[En(IndH4)]ZrCl2/MAO...

In commercial applications of propene hydroformylation the process underwent several modifications predominantly aimed at improvements in product/catalyst separation. The very first version of the process, which was later named the gas recycle process , effected the removal of the product aldehydes from the catalyst solution by applying a large gas recycle in order to evaporate the aldehydes [146, 196, 197]. The catalyst solution consisted of high-boiling aldehyde condensation products (dimers, trimers, and various other aldehyde consecutive products), in which an excess of TPP and the rhodium complex itself was dissolved [198, 199]. In order to keep the volume of this reaction mixture constant, the reaction conditions had to be maintained in a manner which allowed continuous evaporation of the aldehyde products generated by the hydroformylation reaction... 

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