Facile alcoholysis of l-lactide catalysed by Group 1 and 2 metal complexes

Abstract

Alkyl (S)-lactate and alkyl (S,S)-lactyllactate were rapidly and conveniently synthesized from L-lactide using Group 1 and 2 metal complexes as catalyst in alcohol.

Random copolymerization of l‐lactide and ε‐caprolactone by aluminum alkoxide complexes supported by N2O2 bis(phenolate)‐amine ligands

“…All reagents such as aluminum isopropoxide and trimethyl aluminum were purchased from commercial suppliers and used as received. N , N ‐bis[methyl(2‐hydroxy‐3‐ tert ‐butyl‐5‐methylphenyl)] aminomethylpyridine (L 1 H 2 ), N , N ‐bis[methyl(2‐hydroxy‐3‐ tert ‐butyl‐5‐methylphenyl)]‐ N ′, N′ ‐dimethylethylenediamine (L 2 H 2 ) and N,N ‐bis[methyl(2‐hydroxy‐3‐ tert ‐butyl‐5‐methylphenyl)]‐ N′ , N′ ‐diethylethylenediamine (L 3 H 2 ), L 1 AlO i Pr ( 1 ), L 2 AlO i Pr ( 2 ), L 3 AlO i Pr ( 3 ), and isopropyl ( s )‐lactate were synthesized according to literature with minor modification. ε‐CL were dried over CaH 2 overnight at room temperature and distilled under vacuum prior to use, then stored at −30 °C under N 2 atmosphere.…”

“…All reagents such as aluminum isopropoxide and trimethyl aluminum were purchased from commercial suppliers and used as received. N,N-bis[methyl 38 36 and isopropyl (s)-lactate 39 were synthesized according to literature with minor modification. ε-CL were dried over CaH 2 overnight at room temperature and distilled under vacuum prior to use, then stored at −30 C under N 2 atmosphere.…”

The Chemical Recycling of Polyesters for a Circular Plastics Economy: Challenges and Emerging Opportunities

“…Alkyl lactyllactates, the dimeric precursor to lactate esters, have also attracted interest owing to properties akin to their monomer. [5] Group I, [119,141] group II [119][120][121]141] and Al III [141,181,182] have been reported, although primarily limited to the alcoholysis of lactide, with the exception of work by Sobota and coworkers. [141] We identify this as an emerging area of opportunity, particularly with regards to translating such catalysts to PLA.…”

“…[ 5 , 118 ] Recently, the metal‐mediated alcoholysis of lactide has been shown to be an effective alternative. [ 119 , 120 , 121 ] However, this method is arguably an inefficient use of a direct PLA precursor and fails to utilise the PLA waste stream. We will therefore focus on PLA transesterification methods.…”

Syntheses and chemical transformations of glycolide and lactide as monomers for biodegradable polymers

“…Other approaches to lactide alcoholysis are associated with various homogeneous and heterogeneous catalysts based on inorganic and metal-organic compounds. Phomphrai et al proposed to use the commercially available amides of alkali and alkaline earth metals MN(SiMe3)2 as catalysts for the alcoholysis of L-lactide [288]. The alcoholysis of L-lactide with methanol to methyl-L-lactyl lactate in the presence of Li, Na, and K amides results in 48%, 60%, and 84% yields, respectively.…”