2022年5月24日 · A review on the synthesis of (−)-menthol from various raw materials, including the main industrial processes of the companies Symrise, Takasago and BASF and recent literature on this topic.

It begins with the synthesis of the terpene limonene, followed by hydroxylation, and then several reduction and isomerization steps. More specifically, the biosynthesis of (−)-menthol takes place in the secretory gland cells of the peppermint plant. The …

2024年3月27日 · Symrise Process (formerly know as Haarmann & Reimer process) (US Patent 3,943,181 (Mar 9 1976)) – In this process (Fig 6.2), thymol is synthesized from m-cresol. Catalytic hydrogenation gave a mixture of Menthols from which menthols were first obtained as a racemic mixture by careful fractional distillation.

2022年10月21日 · Recently one-pot synthesis of menthol in a trickle bed reactor has been investigated. Catalyst suffers only minor deactivation in transformation of citronellal to menthol, while more severe catalyst deactivation occurred in transforming citral to menthols.

(−)-Menthol is one of the most popular aroma compounds worldwide. While in the past mostly extracted from mint plants, today (−)-menthol synthesis from other raw materials is becoming more relevant. Common starting materials for menthol synthe-sis are mcresol, citral and myrcene, but also substrates like menthone, mono-- and

2022年4月25日 · One-pot synthesis of menthols from citronellal and citral was demonstrated in a trickle bed reactor over nickel supported on extrudates comprising H-Beta-38 and sepiolite as a binder. The composite catalyst exhibited both Brønsted and Lewis acid sites with their ratio of 0.60 and nickel clusters of ca. 23 nm.

2014年12月1日 · The present work systematically investigates the first step of menthol synthesis, i.e. the cyclization of citronellal, where H-BEA was identified as useful catalyst, and then the one-pot transformation of citronellal to menthols on bifunctional metal (Pd, Pt, …

4 天之前 · Menthol is produced as a mixture of l-menthol, which has industrial value, and d-menthol, a byproduct with significantly inferior taste and odor (see schematic). Reducing the proportion of d-menthol and improving the purity of l-menthol is a critical challenge in industrial synthesis, requiring advanced chemical synthesis processes.

Menthol isomers are high-value monoterpenoid commodity chemicals, produced naturally by mint plants, Mentha spp. Alternative clean biosynthetic routes to these compounds are commercially attractive. Optimization strategies for biocatalytic terpenoid production are mainly focused on metabolic engineering of the biosynthesis pathway within an ...

2015年2月9日 · We have developed a one-pot (bio)synthesis of (1R,2S,5R)-( )-menthol and (1S,2S,5R)-(+)-neomenthol − from pulegone, using recombinant Escherichia coli extracts containing the biosynthetic genes for an “ene”-reductase (NtDBR from Nicotiana tabacum) and two menthone dehydrogenases (MMR and MNMR from Mentha piperita).