Telomerization of 1,3-butadiene with various alcohols by Pd/TOMPP catalysts: new opportunities for catalytic biomass valorization

Abstract

The telomerization of 1,3-butadiene with various alcohols has been investigated using a catalyst based on a Pd(acac) 2 precursor and a phosphine ligand, TOMPP (TOMPP = tris-(omethoxyphenyl)phosphine). We were able to demonstrate the capability of the catalyst to telomerize 1,3-butadiene with various multifunctional nucleophiles having primary and secondary alcohol functions. High yields of telomer products (>98%) were obtained in very short reaction times (<2 h). The telomerization activity and selectivity of the Pd/TOMPP complex was strongly influenced by the type of alcohol used as substrate. When diols were used, telomerization of 1,3-butadiene with 1,2-propanediol and 1,2-butanediol afforded the highest yield of monotelomer (over 70%) and for 1,2-butanediol a turnover frequency (TOF) of 300 000 h -1 was reached, combined with a turnover number (TON) of 7800.Scheme 1 Telomerization of 1,3-butadiene with nucleophile HX over Pd catalysts.

Base‐free Pd/TOMPP‐Catalyzed Telomerization of 1,3‐Butadiene with Carbohydrates and Sugar Alcohols

“…No attempt was made to detect or quantify possible volatile byproducts, as they are not expected to be formed to a significant extent. [4,5] Substrate standards were prepared by peracetylation, and their authenticity and purity were checked by 1 H NMR and LC-ESI-MS (see Supporting Information). Substrate conversions (X S ) were determined either by GC or LC-ESI-MS. Butadiene conversions (X B ) were determined gravimetrically with an accuracy of 1 g. Turnover numbers were calculated using the formula: where N S represents the initial amount of substrate.…”

“…Our previous investigations on the telomerization of 1,3-butadiene with glycerol [4] and with various glycols [5] already demonstrated that the Pd/TOMPP (TOMPP: tris(2-methoxyphenyl)-phosphine) system is a highly active catalyst for the conversion of various biobased alcohols. These encouraging results prompted us to extend the substrate scope to include the natural sugars as nucleophiles in the telomerization of 1,3-butadiene, as they constitute the major components of biomass.…”

Pd-Catalyzed Telomerization of 1,3-Dienes with Multifunctional Renewable Substrates: Versatile Routes for the Valorization of Biomass-Derived Platform Molecules

“…6). TOMPP had previously given the best results in a ligand screening study for glycerol telomerization (vide infra) [77]. The Pd/ TOMPP system showed the highest activity with 80% conversion after 66 min at 80 C, using only 0.01 mol% Pd (relative to ethylene glycol) and a 1,3-butadiene/ ethylene glycol ratio 2.…”

“…The use of these catalysts in the telomerization of methanol and ethylene glycol resulted in a remarkable shift in Fig. 6 Conversion and selectivity of the Pd/TOMPP-catalyzed telomerization with various diols [77] selectivity from the classical C8 telomers to higher telomers containing mostly C16 carbon chains. A selectivity of up to 48% is reported for higher telomers of EG, which consist for >90% of C16 telomers.…”

“…The volatility of the glycerol Fig. 7 TOFs determined at low conversion for various diols using the Pd/TOMPP catalyst under solventless conditions [77,84] price has dampened this initial interest to a certain extent, but has not limited the inherent potential of glycerol to play a major role as renewable building block.…”