636-60-2

Upstream product

• 13423-15-9 3-methyltetrahydrofuran 
• 3724-65-0 2-butenoic acid 
• 59107-74-3 3-bromo-4-methyl-2,5-furandione 
• 556-56-9 allyl iodid 
• 52808-16-9 2-cyano-2-methyl-succinic acid diethyl ester 
• 60298-17-1 2-cyano-3-methyl-succinic acid diethyl ester 
• 64-17-5 ethanol 
• 10544-63-5 ethyl crotonate 
• 151-50-8 potassium cyanide 
• 78-75-1 1,2-Dibromopropane 
• 473-81-4 glyceric acid 
• 498-23-7 citraconic acid 
• 498-24-8 Mesaconic acid 
• 87-69-4 L-Tartaric acid 

Downstream Products

• 21307-96-0 methyl 2-methylsuccinate 
• 5652-58-4 2-carboxyisobutyrophenone 
• 4676-51-1 Diethyl 2-methylsuccinate 
• 498-24-8 Mesaconic acid 
• 32980-25-9 2-methylsuccinic acid 1-methyl ester 
• 71-23-8 propan-1-ol 
• 187737-37-7 propene 
• 67-63-0 isopropyl alcohol 
• 15719-64-9 methylammonium carbonate 
• 4100-80-5 2-methylsuccinic anhydride 
• 123-38-6 propionaldehyde 
• 107-92-6 butyric acid 
• 105909-89-5 1-(4-methylphenyl)-3-methylpyrrolidine-2,5-dione 
• 33720-38-6 1-(4-methoxyphenyl)-3-methylpyrrolidine-2,5-dione 

Relevant academic research and scientific papers

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

Citric acid is an important biomass-derived platform chemical for the synthesis of high-value organic acids, such as itaconic acid (ICA), 2-methylsuccinic acid (MSA) and tricarballylic acid (TCA). However, these reactions frequently encounter low efficiency and severe leaching of catalysts imposed by the acidity of citric acid under hydrothermal conditions, limiting their practical applications. Here, we report that highly acid- and etching-resistant monoclinic zirconium dioxide (m-ZrO2) exhibited high catalytic efficiency in the conversion of citric acid to ICA via sequential dehydration and decarboxylation steps, providing a high yield of 70.3% at 180 °C on m-ZrO2 (calcined at 300 °C). The correlation between the activity of the m-ZrO2 catalysts and their acid-basicity demonstrates that the synergistic effect of acidic and basic sites facilitates the rate-determining dehydration step for the citric acid conversion to ICA. On the bifunctional catalysts, Pt and Pd nanoparticles supported on P25 and anatase TiO2, citric acid can be selectively converted to MSA and TCA, respectively, with yields as high as 83.1% and 64.9%. The hydrogenation activity of the bifunctional catalysts was found to be crucial for regulating the relative rates of the decarboxylation and hydrogenation steps involved in the selective conversion of citric acid to MSA and TCA. These catalysts showed excellent stability and recyclability in acidic aqueous solutions. This study provides a rationale for tuning catalytic functions required for the green production of important carboxylic acids from citric acid and other biomass-derived feedstocks. This journal is

CATALYST AND METHOD OF HYDROGENATING UNSATURATED COMPOUND WITH MULTI-CARBOXYLIC ACID GROUPS

A method of hydrogenating unsaturated compound with multi-carboxylic acid groups is provided, which includes introducing hydrogen to an unsaturated compound with multi-carboxylic acid groups in the presence of a catalyst to hydrogenate the alkene or alkyne group of the unsaturated compound with multi-carboxylic acid groups without hydrogenating the carboxylic acid groups of the unsaturated compound with multi-carboxylic acid groups. The catalyst includes a support, and palladium and metal oxide loaded on the support.

Catalytic Aerobic Oxidation of Lignocellulose-Derived Levulinic Acid in Aqueous Solution: A Novel Route to Synthesize Dicarboxylic Acids for Bio-Based Polymers

The world is facing grand and ever-increasing pressures on energy and environmental issues. Using carbon-neutral biomass to prepare monomers such as dicarboxylic acids for degradable polymers is of great significance and an urgent but challenging task. Herein, we report a catalytic route for the synthesis of 2-hydroxy-2-methylsuccinic acid, an excellent monomer: e.g., it is able to remarkably enhance the comprehensive properties of polybutylene succinate as shown herein. By catalytic aerobic oxidation of levulinic acid, a bulk platform chemical derived from lignocellulose, the target product was obtained with a very high selectivity of up to ca. 95%. The mild reaction conditions below 100 °C in water and the low-cost reusable heterogeneous catalyst further make the process highly attractive for applications. This process was also found to be effective for the conversion of homologues of levulinic acid to dicarboxylic acids. We studied the C-C bond rearrangement and the roles of catalysts in the reaction that are highly likely involved in a superoxide anion radical mechanism. This study may provide inspiration for the synthesis of bio-based dicarboxylic acids via alternative routes.

1,3,2-Diazaphospholenes Catalyze the Conjugate Reduction of Substituted Acrylic Acids

The potent nucleophilicity and remarkably low basicity of 1,3,2-diazaphospholenes (DAPs) is exploited in a catalytic, metal-free 1,4-reduction of free α,β-unsaturated carboxylic acids. Notably, the reduction occurs without a prior deprotonation of the carboxylic acid moiety and hence does not consume an additional hydride equivalent. This highlights the excellent nucleophilic character and low basicity of DAP-hydrides. Functional groups such as Cbz group or alkyl halides which can be problematic with classical transition-metal catalysts are well tolerated in the DAP-catalyzed process. Moreover, the transformation is characterized by a low catalyst loading, mild reaction conditions at ambient temperature as well as fast reaction times and high yields. The proof-of-principle for a catalytic enantioselective version is described.

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

Strong concerns about the toxicity and endocrine disrupting properties of widespread phthalate plasticizers stimulate the demand for safe and preferably biobased alternatives. Citric acid forms in this respect an excellent and abundant platform chemical for the production of valuable plasticizers. Here, we report a new and direct synthesis route for propane-1,2,3-tricarboxylic acid (PTA) from citric acid via a sequential one pot dehydration-hydrogenation process. This saturated triacid can serve as a basis for the production of tricarballylate esters via esterification, which have been shown to possess excellent plasticizing properties in vinyl resins. In the presence of a solid acid H-Beta zeolite and Pd/C hydrogenation catalyst, yields up to 85% of PTA were obtained under mild reaction conditions and in water as a green solvent. Partial dealumination of the H-Beta zeolite by citric acid could be counteracted by reincorporating aluminium into the framework of the recycled H-Beta zeolite through realumination, regenerating a significant fraction of the initial activity of the catalytic system. The success of the realumination procedure was verified via MAS NMR spectroscopy.

Sustainable electroorganic synthesis of lignin-derived dicarboxylic acids

The oxidative ring opening of lignin-derived alkylated cyclohexanols to bio-based alkylated dicarboxylic acids is successfully performed by an electrocatalytic conversion. To establish this transformation as a green method, we developed a simple protocol for the anodic oxidation at nickel oxide-hydroxide (NiOOH) foam anodes in caustic soda in both a batch and flow electrolysis approach.

Regioselective Hydrogenation of Itaconic Acid to Γ-Isovalerolactone by Transition-Metal Nanoparticle Catalysts

Current methods for hydrogenation of bio-derived itaconic acid (IA) lead to a mixture of isomeric lactone products. Transition-metal nanoparticles (TM-NPs), in situ-generated through thermolysis of TM(0) (Ru, Fe, W, Cr) carbonyls, in particular Ru-NPs, were found to catalyze regioselective hydrogenation of IA by syngas (2 H2/CO) into γ-isovalerolactone (GiVL) in approximately 70 % isolated yield. Key sustainability features of this new route include: a one-pot direct transformation of bio-renewable IA into value-added GiVL selectively, use of inexpensive and renewable syngas in aqueous solution, and development of a supported recyclable NP catalyst system, Al2O3-Ru-NPs.

METHOD FOR THE PRODUCTION OF METHYLSUCCINIC ACID AND THE ANHYDRIDE THEREOF FROM CITRIC ACID

A process for the preparation of methylsuccinic acid in any form, including its salts, its mono- and diester derivatives and the anhydride thereof, which comprises reacting citric acid or a derivative thereof in decarboxylation conditions, said process comprising (i) reacting citric acid or mono- and diester derivatives thereof in a non- aqueous solvent, specifically excluding alcohols, on a metallic catalyst at a temperature between 50 to 400°C and under a partial hydrogen pressure from 0.1 to 50 bar or (ii) reacting citric acid or any salt thereof or mono-, di- and triester derivatives thereof on a metallic catalyst in solvents comprising at least 5% water, at a temperature of from 50 to 400°C under a hydrogen partial pressure from 0.1 to 400 bar

Stabilising Ni catalysts for the dehydration-decarboxylation-hydrogenation of citric acid to methylsuccinic acid

A new reaction sequence of dehydration-decarboxylation-hydrogenation to transform citric acid into methylsuccinic acid has recently been developed using Pd as a noble metal catalyst in water. In this work Ni catalysts were investigated as low cost, non-noble metal alternatives. Several home-made and commercial catalysts were screened for this reaction. Citric acid was very reactive and full conversions were readily obtained in all cases. However, the selectivity to methylsuccinic acid was initially low, since typical Ni catalysts were not stable and therefore not able to hydrogenate the formed CC double bonds. Due to the lower hydrogenation activity of Ni compared to Pd, new side products appeared. Particularly, hydration of the CC double bonds made the reaction network more complex in this case. Fortunately, the formation of all hydration products-even the rather stable lactone, β-carboxy-γ-butyrolactone-was eventually shown to be completely reversible. Three routes were then studied to stabilise Ni catalysts and to enable the Ni catalyzed conversion of citric acid to methylsuccinic acid; partial neutralisation of the acid reactant, adding Fe to Ni/ZrO2 or to the reaction mixture and coating Ni particles with carbon, all proved to stabilise Ni and all resulted in high to very high methylsuccinic acid yields. Furthermore, the role of Fe was unravelled by performing reference reactions with different Fe compounds and by in depth characterisation of the NiFe/ZrO2 catalyst. Finally, the reaction conditions were optimised using the carbon-coated Ni nanoparticles and kinetic profiles were recorded to confirm the extended reaction network.

Highly selective one-step dehydration, decarboxylation and hydrogenation of citric acid to methylsuccinic acid

The one-step dehydration, decarboxylation and hydrogenation of the bio-based and widely available citric acid is presented. This reaction sequence yields methylsuccinic acid with yields of up to 89%. Optimal balances between the reaction rates of the different steps were found by varying the hydrogenation catalyst and the reaction parameters (H2 pressure, pH, temperature, time and catalyst-to-substrate ratio).