Triphenylphosphane‐Functionalised Amphiphilic Copolymers: Tailor‐Made Support Materials for the Efficient and Selective Aqueous Two‐Phase Hydroformylation of 1‐Octene

Abstract

Amphiphilic copolymers (random P1 and block P2) based on 2-oxazolines were synthesised with triphenylphosphane ligands covalently linked to the polymers by means of a metal-free synthesis route. The resulting macroligands were used in the aqueous two-phase hydroformylation of 1-octene. The influence of the polymer architecture (random and block copolymers) on activity and selectivity of the hydroformylation reaction was investigated and compared with that of nonfunctionalised copolymers (random P3 and block P4) and Rh(I)/triphenylphosphane trisulfonate as a water-soluble catalyst. The highest activities were observed for the random copolymer P1 (p=50 bar, T=100 degrees C, c=8 x 10(-4) mol L(-1)) with a turnover frequency (TOF) of 3700 h(-1), whereas the corresponding block copolymer P2 reached TOF numbers of 1630 h(-1). Additionally, both macroligands indicated efficient suppression of isomerisation and led to almost constant n/iso selectivities of about 3 after complete substrate conversion. Copolymers P3 and P4 showed, under identical reaction conditions, strong isomerisation after 40-60 % conversion (n/iso approximately 0.7) and maximum activities of 1560 h(-1) (P3) and 1330 h(-1) (P4) at a concentration of 5 x 10(-3) mol L(-1).

Cascade Reactions in Polymeric Nanoreactors: Mono (Rh)‐ and Bimetallic (Rh/Ir) Micellar Catalysis in the Hydroaminomethylation of 1‐Octene

“…[17] The triphenylphosphane functionalized poly(2-oxazoline) block copolymer was synthesized by sequential polymerization of 2-methyl-2-oxazoline to form the hydrophilic block followed by a mixture of 2-nonly-2-oxazoline and 2-(5-(amino-tert-butoxycarbonyl)-pentyl)-2-oxazoline to give the hydrophobic block using methyltriflate as initiator and piperidine as highly efficient termination agent. The free primary amine groups were obtained after deprotection of the polymer in methanolic hydrochloric acid.…”

“…per amine function) and dicyclohexylcarbodiimide (DCC) as coupling reagent. [17] The polymer structure (Figure 1) was analyzed by 1 H and 31 P NMR spectroscopy. 90% of the amino groups were reacted with 4-diphenylphosphano benzoic acid.…”

“…Amphiphilic, triphenylphosphane functionalized poly(2-oxazoline) block copolymer. [17] Two reasons might account for this observation. Either lower CO partial pressure or deactivation of the catalyst by amines is responsible for the low hydroformylation rate (HF; Table 1, exp.…”

“…[5,16] Especially the latter approach has been studied intensively in our group in the Ruthenium catalyzed hydroformylation of 1-octene with phosphane functionalized block copolymers. [17] The excellent results with respect to activity and selectivity should be therefore the starting point to study the hydroaminomethylation where the hydroformylation is the first step in the three step reaction cascade and thereby overcome some of the limitations when simply using surfactants in the aqueous-two phase hydroaminomethylation. [18] …”

Poly(2‐oxazoline)s based on fatty acids

“…Block copolymers functionalized with a catalytic ruthenium(II) complex were successfully applied for aqueous ring-closing metathesis [61] as well as for the formation of poly(acetylene) latex particles [62]. In addition, a rhodium functionalized block copolymer was prepared and subsequently applied for micellar catalysis of hydrogenation reactions [63], hydroamino-methylation reactions [64] as well as hydroformylations [65,66]. For the latter hydroformylation reactions triphenylphosphine decorated block copolymers were prepared that were subsequently applied for micellar catalysis in a biphasic system, i.e., the micellar catalysts are present in the aqueous phase while the substrate and product are present in the lipophilic phase as depicted in Figure 7.…”