Selective defunctionalization of citric acid to tricarballylic acid as a precursor for the production of high-value plasticizers

Abstract

In presence of a solid acid H-Beta zeolite and Pd/C catalyst, citric acid was converted to tricarballylic acid via a one-pot sequential dehydration-hydrogenation process with a yield up to 85% and a selectivity exceeding 90%.

Developments of biobased plasticizers for compostable polymers in the green packaging applications: A review

“…At industrial scale, more than 50 kinds of CAPs have been produced where tributyl citrate (TBC) and acetyl tributyl citrate (ATBC) have been explored in‐depth and industrialized due to their high‐performance 46 . In essence, TBC and triethyl citrate (TEC) are produced via esterification of citric acid, which is often followed by butyrylation or acetylation of the tertiary hydroxyl group to produce ATBC, butyryl trihexyl citrate (BTHC), and acetyl triethyl citrate (ATEC), respectively 49 . The efficiency of these plasticizers is comparable to di‐2‐ethylhexyl phthalate (DEHP), however ATBC is found to be more prone to leaching compared to DEHP 49 …”

“…In essence, TBC and triethyl citrate (TEC) are produced via esterification of citric acid, which is often followed by butyrylation or acetylation of the tertiary hydroxyl group to produce ATBC, butyryl trihexyl citrate (BTHC), and acetyl triethyl citrate (ATEC), respectively 49 . The efficiency of these plasticizers is comparable to di‐2‐ethylhexyl phthalate (DEHP), however ATBC is found to be more prone to leaching compared to DEHP 49 …”

“…A novel class of CAPs was developed from propane‐1,2,3‐tricarboxylic acid (PTA) which was synthesized used esterification method in one step from citric acid through dehydration‐hydrogenation process. This PTA can be utilized to produce tricarballylate esters, which possess superior plasticizing efficiency in vinyl resins 49 . Acetylated‐fatty acid methyl ester‐citric acid ester is another CAP developed using waste cooking oil and citric acid as raw material 65 as shown in Figure 10.…”

Efficient conversion of bio-renewable citric acid to high-value carboxylic acids on stable solid catalysts

“…14 Meanwhile, starting from citric acid, many value-added acids can be synthesized, such as itaconic acid (ICA), aconitic acid (ACA), citraconic acid (CCA) and methacrylic acid (MAA), as shown in Scheme 1. [15][16][17][18][19][20][21] Among these products, ICA has gained increasing attention as one of the "top 10" most promising platform chemicals from biomass, identified by the U.S. Department of Energy. 22 It can be used as a versatile intermediate in the synthesis of Scheme 1 Conversion of citric acid to representative high-value carboxylic acids.…”

“…35 Recently, Pd and Ni catalysts have been applied for the conversion of citric acid to MSA and TCA in a one-step process. 15,18,21 For example, De Vos and co-workers reported the conversion of citric acid into MSA on Pd/BaSO 4 in the presence of caustic NaOH. 15 A NiFe-based catalyst was also used in this reaction; 18 however, at least 5% of Ni and 93% of Fe leached into the aqueous solution, leading to severe catalyst deactivation, imposed by the acidity of citric acid under the hydrothermal conditions.…”