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Production of biodiesel is a renewable and pollution free source but it increases co-product i.e. crude glycerol. This paper demonstrates applications of the side product in an efficient and cost effective manner. The crude glycerol hence produced can be utilized in varied industries and can be used as precursor for the production of various products having better economic significance. The majority of crude glycerol is used as feedstock for production of other value-added chemicals. The utilization of glycerol in production of Glycerol trinitrate, Tartronic acid and Glyceric acid has been reported successfully.

High-performance electrocatalysts with excellent activity and selectivity hold the key to the electrochemical conversion of glycerol. Herein, well-defined bimetallic Au@Ag and trimetallic PdAu@Ag core-shelled nanoparticles were fabricated using a seed-mediated growth process and further examined as electrocatalysts for glycerol oxidation in both alkaline and acidic solutions. The activity of the catalysts was evaluated via cyclic voltammetry, linear sweep voltammetry and chronoamperometric measurements. The Au@Ag and PdAu@Ag nanoparticles are highly active in alkaline solutions, but inactive in acidic solutions. In alkaline solutions, the PdAu@Ag and Au@Ag nanoparticles show current densities of 3.94 and 2.57 mA cm−2, which are 4.3 and 25.7 times those of the commercial Pd/C and Au/C catalysts, respectively. The products of glycerol electro-oxidation were analyzed by high performance liquid chromatography (HPLC). Three major products, namely dihydroxyacetone (DHA), glyceric acid, glyceraldehyde and five minor products including oxalate acid, tartronic acid, formic acid, glycolic acid (GA) and glyoxylic acid were detected. Notably, a remarkable DHA selectivity of 70.1% was obtained from the PdAu@Ag catalyst at 0.9 V. The Au@Ag yields the largest GA selectivity of 31.6% at 1.1 V. The PdAu@Ag tends to yield more C3 products at high applied potentials.

Isoprothiolane (IPT) was one of the most commonly used pesticides around the world. It was reported to be the highest concentration and frequency of detection of 13 most commonly used pesticides in Mekong Delta recently. The oxidation degradation kinetic of ozone and chlorine with IPT and the identification of the degradation products was investigated in this research. The results showed that both ozone and chlorine oxidized IPT rapidly under typical water treatment condition, and that both reactions followed second order reaction kinetics. The ozone reaction rates exhibited no pH dependence with the rate constant of 247.1 (±11.0) M−1s−1 at 25 °C, whereas chlorine reaction rates increased dramatically with decreasing pH. The rate constant for hypochloric acid was 73.3 (±3.1) M−1s−1 at 25 °C, while the reaction of hypochlorite was negligible. The degradation products by chlorine and ozone were identified by LC-MS/MS and the reaction pathways were proposed. The thioether and the carbon-carbon double bond in IPT were the reactive sites during chlorine and ozone oxidation. The thioether group was oxidized into sulfoxide and further sulfone group, and the carbon-carbon double bone were cleaved to form diisopropyl ester of malonic acid, diisopropyl ester of tartronic acid and diisopropyl ester of ketomalonic acid monohydrate. Compared to ozone reaction, it was more complicated for chlorine reaction, which yielded chlorine substituted, hydroxylated and dithiolane ring-opening products.

Catalytic transformation of glycerol to value-added products has attracted the attention of scientists all over the world. Among various transformations, selective oxidation of glycerol with molecular oxygen to dihydroxyacetone, glyceric acid, glyceraldehydes, and tartronic acid is challenging both from the viewpoint of academic research and industrial application. Herein, we review the recent progresses in the selective oxidation of glycerol under base-free conditions. Those catalysts widely reported for the selective oxidation of the terminal hydroxyl and secondary hydroxyl groups in glycerol, such as monometallic Au, Pt, and Pd NPs, and bimetallic Au-Pt, Au-Pd, Pt-Bi, Pt-Sb, and Pt-Cu, were compared and discussed in detail. The reaction mechanism over Pt-based catalysts, possible catalyst deactivation, and the corresponding improvements are presented. Further, the recent progresses in the continuous oxidation of glycerol in fixed bed reactors and its excellent selectivity in the formation of dihydroxyacetone are highlighted.

International audience; In this work, we highlight the feasibility of new efficient catalytic processes by laser excitation, exemplified in the reaction of oxidation of glycerol over catalysts based on supported gold nanoparticles. We show that this catalytic oxidation reaction can efficiently proceed via laser excitation of surface plasmon resonance of gold nanoparticles, inducing local thermal heating effect. While the reaction did not occur in the absence of any external heat source, with this original approach, 88% of glycerol was converted after 2 h, leading to the formation of glyceric acid and tartronic acid as main products. The photonic activation led to 2.5 times more efficient conversion than an equivalent thermal activation by conventional heating source. Investigations of the laser power and the nature of support catalyst revealed a significant contribution of electron transfer from plasmonic nanoparticles to TiO² in the oxidation reaction.

The SMB unit developed by the Laboratory of Separation and Reaction Engineering (FlexSMB-LSRE®) was used to perform tartronic acid (TTA) and glyceric acid (GCA) separation and to validate the mathematical model in order to determine the optimum operating parameters of an industrial unit. The purity of the raffinate and extract streams in the experiments performed were 80% and 100%, respectively. The TTA and GCA productivities were 79 and 115 kg per liter of adsorbent per day, respectively and only 0.50 cubic meters of desorbent were required per kilogram of products. Under the optimum operating conditions, which were determined through an extensive simulation study based on the mathematical model developed to predict the performance of a real SMB unit, it was possible to achieve a productivity of 86 kg of TTA and 176 kg of GCA per cubic meter of adsorbent per day (considering the typical commercial purity value of 97% for both compounds) with an eluent consumption of 0.30 cubic meters per kilogram of products.

Over the past decades, research efforts are being devoted into utilizing the biomass waste as a major source of green energy to maintain the economic, environmental, and social sustainability. Specifically, there is an emerging consensus on the significance of glycerol (an underutilised waste from biodiesel industry) as a cheap, non-toxic, and renewable source for valuable chemicals synthesis. There are numerous methods enacted to convert this glycerol waste to tartronic acid, mesoxalic acid, glyceraldehyde, dihydroxyacetone, oxalic acid and so on. Among these, the green electro-oxidation technique is one of the techniques that possesses potential for industrial application due to advantages such as non-toxicity process, fast response, and lower energy consumption. The current review covers the general understanding on commonly used techniques for alcohol (C1 & C2) conversion, with a specific insight on glycerol (C3) electro-oxidation (GOR). Since catalysts are the backbone of chemical reaction, they are responsible for the overall economy prospect of any processes. To this end, a comprehensive review on catalysts, which include noble metals, non-noble metals, and non-metals anchored over various supports are incorporated in this review. Moreover, a fundamental insight into the development of future electrocatalysts for glycerol oxidation along with products analysis is also presented.

Palladium-bismuth nanoparticles were supported into strongly basic anion-exchange resin of gel-type and tested as catalysts for the selective oxidation of glycerol with molecular oxygen at atmospheric pressure. Detailed study of the precursors preparation and reduction were undertaken. The catalyst 3%Pd-1%Bi where the bismuth was deposited on the palladium particles (3.4 nm) exhibited at 95% glycerol conversion more than 63% yield toward glyceric acid and tartronic acid after 3 h of reaction. The catalyst maintains practically similar catalytic performance as in fresh state for at least five consecutive catalytic cycles without extra catalyst treatment and reactivation.

As a dicarboxylic acid with the structural formula HOOCCH (OH) COOH, tartronic acid is considered as an inhibitor of the transformation of carbohydrates into fat under fat-deficient diet conditions. However, the effect of tartronic acid on lipogenesis under high-fat diet conditions has yet to be established. In this work, we investigated the regulatory role of tartronic acid in lipogenesis in 3T3-L1 adipocytes and C57BL/6J mice. The results confirmed that tartronic acid promoted weight gain (without affecting food intake) and induced adipocyte hypertrophy in epididymal white adipose tissue and lipid accumulation in the livers of high-fat diet-induced obese mice. In vitro, tartronic acid promoted 3T3-L1 adipocyte differentiation by increasing the protein expression of FABP-4, PPARγ and SREBP-1. Moreover, the contents of both acetyl-CoA and malonyl-CoA were significantly upregulated by treatment with tartronic acid, while the protein expression of CPT-1β were inhibited. In summary, we proved that tartronic acid promotes lipogenesis by serving as substrates for fatty acid synthesis and inhibiting CPT-1β, providing a new perspective for the study of tartronic acid.

Magnetically separable monometallic and bimetallic Au and Pt NPs anchored on TiO2 nanocomposite were prepared using dahlia flower extract through a greener approach. The prepared nanoparticles (NPs) act as an efficient active metal-based catalyst for glycerol oxidation reaction (GOR) and organic compounds reduction reaction (ORR). The phytochemicals present in dahlia flower extract acts as reducing and stabilizing agent for the development of metal NPs on TiO2 surface. For bimetallic (Fe3O4@TiO2–AuPt) NPs, the conversion efficiency for GOR was found to be 2-fold higher than those of monometallic NPs. The products of GOR over magnetically separable monometallic and bimetallic catalysts were analyzed by HPLC and products such as formic acid (FA), glycolic acid (GCA), glyceric acid (GLA), and tartronic acid (TA) were detected. In addition, ORR of 4-nitrophenol (4-NP), methylene blue (MB) and congo red (CR) in the existence of sodium borohydride (NaBH4) were studied. It was found that the reduction reactions were completed within a few seconds for mono- and bimetallic nanocomposites. Comparatively, Fe3O4@TiO2–AuPt nanocomposite showed much higher efficacy (8, 6 and 5 s) for 4-NP, MB and CR reduction along with very good stable catalytic activity (∼98%) after six cycles. We hypothesize that the improved yield in GOR and faster reduction in ORR by Fe3O4@TiO2–AuPt nanocomposites are related to the synergistic effect of metal alloy formation and support materials.

Au-Pt bimetallic catalysts were supported on different supports, including acidic (TiO 2 and CeO 2 ), basic (MgO, Mg(OH) 2 , (MgCO 3 ) 4 Mg(OH) 2 , ZnO, and CaCO 3 ), and amphoteric (Al 2 O 3 and hydrotalcite) supports with the aim to study the effect of the acid/base properties of supports upon the performance of Au-Pt bimetallic catalysts in glycerol oxidation. The results showed that these properties significantly affected the selectivity of products. The selectivity to glyceraldehyde was inversely proportional to the strength of supports’ basic sites, and the selectivity to tartronic acid (or glycolic acid, or glyoxalic acid) was proportional to the strength of basic sites. In contrast, the selectivity to glyceric acid was neither proportional to the strength of basic sites nor proportional to the strength of acid sites. The doping of another weaker basic site also affected the selectivity to glyceric acid. Furthermore, the role of the acid/base nature of the supports in affecting the products’ distribution is proposed.

Solutions of ribose, glucose, and sucrose in water and phosphate buffer were treated with non-thermal plasma generated by using a dielectric barrier discharge (DBD) device and the oxidation products were characterized by 1H NMR and GC–MS. Our results demonstrate that these sugars are decomposed to formic acid, glycolic acid, glyceric acid, tartronic acid, tartaric acid, acetic acid, and oxalic acid after direct exposure to DBD plasma. The concentrations of these compounds are time-dependent with plasma treatment. The decomposition mechanisms of these sugars under the DBD plasma are also proposed in this study.

This is a comparative study of photolytic degradation under exposure to UV254 nm and solar-simulator irradiation of a mixture of eight equally concentrated relevant micropollutants in the presence of H2O2 and Fe(II) in ultrapure water, Lake Geneva water, and effluent from a wastewater treatment plant (WWTP). The electron-spin resonance (ESR) experiments point to a low efficiency of singlet oxygen formation by the mixture of micropollutants. This finding corroborates with the chemical stability of the micropollutants under UVC irradiation (in decreasing order: gabapentin, metformin, metoprolol, atenolol, clarithromycin, primidone, methylbenzotriazole, and benzotriazole). The oxidation rate increased in the presence of low-concentration H2O2 and Fe(II), except for metformin and gabapentin. Gabapentin and metformin were the most persistent compounds, less than 24% were removed after 60 minutes of UV254/H2O2/Fe(II) treatment. The low micropollutant removal rates were observed in WWTP effluent and lake water, and using sunlight simulation. Guanylurea, phenol, oxalic acid, tartronic acid, glycolic acid, oxamic acid, and maleic acid, could also be detected as fragmental oxidation products. Furthermore, up to 300 µg/L of nitrate and ammonia were identified as final degradation products. Ecotoxicological tests showed that the degradation products are more toxic for algae Chlamydomonas reinhardtii than the parent compounds themselves.

Selective oxidation of glycerol over Pt-based supported catalysts has been widely investigated for synthesis of value-added carboxylic acids. Herein, the oxidation mechanism of glycerol to carboxylic acids on Pt (111) facet using molecular oxygen as oxidant in base-free liquid phase conditions was systematically studied by density functional theory (DFT) calculation. It is found that there is a co-dissociation reaction of oxygen and water to form adsorbed hydroxyl and oxygen atom, resulting in the formation of three active sites (Pt*, Pt-O* and Pt-OH*) to participate in oxidation reactions. The oxidation of glycerol involves four key steps: dehydrogenation of OH group, dehydrogenation of C H group, aldehydes oxidation and cleavage of C C bond. Calculation result reveals that the key to enhance the catalytic activity of glycerol oxidation to carboxylic acids (mainly glyceric acid and tartronic acid) is to polarize the surface of Pt with the formation of Pt-OH* or other active sites. Furthermore, the improvement of carboxylic acid selectivity depends on the incorporation of a second active site to Pt in order to prevent the C C bond cleavage of the thermodynamically stable intermediate of glyceric acid.

Bi has been widely employed as a modifier for Pd and Pt based catalyst mainly in order to improve selectivity. We found that when Bi was added to the bimetallic system AuPd, the effect on activity in alcohol oxidation mainly depends on the amount of Bi regardless its position, being negligible when Bi was 0.1 wt% and detectably negative when the amount was increased to 3 wt%. However, the selectivity of the reactions notably varied only when Bi was deposited on the surface of metal nanoparticles suppressing parallel reaction in both benzyl alcohol and glycerol oxidation. After a careful characterization of all the catalysts and additional catalytic tests, we concluded that the Bi influence on the activity of the catalysts could be ascribed to electronic effect whereas the one on selectivity mainly to a geometric modification. Moreover, the Bi-modified AuPd/AC catalyst showed possible application in the production of tartronic acid, a useful intermediate, from glycerol.

The carbon supported Au nanoparticles (Au-NPs) catalyst with a small average size (3.5 nm) and narrow size distribution (2–6 nm) was synthesized by a solution phase-based nanocapsule method. The reactivity of glycerol oxidation on Au/C is much higher than that of methanol and ethylene glycol oxidations in alkaline electrolyte. The anion-exchange membrane-direct glycerol fuel cell (AEM-DGFC) with the Au/C anode catalyst and a Fe-based cathode catalyst shows high performances with both high-purity glycerol and crude glycerol fuel: the open circuit voltages (OCVs) are 0.67 and 0.66 V, and peak power densities are 57.9 and 30.7 mW cm−2 at 80 °C, respectively. Fed with crude glycerol, the Au/C anode catalyst-based AEM-DGFC also demonstrates high performance stability at 80 °C. The product analysis shows that the electrooxidation of glycerol on the Au/C anode catalyst in AEM-DGFCs favors production of deeper-oxidized chemicals: tartronic acid, mesoxalic acid and oxalic acid, which leads to higher fuel cell's Faradic efficiency.

Electrocatalytic oxidation of glycerol for cogenerating electricity and higher-valued chemicals on a Pt/C anode catalyst (2.4 nm) in an anion-exchange membrane fuel cell (AEMFC) was investigated. The peak power density of an anion-exchange membrane – direct glycerol fuel cell (AEM-DGFC) with 1.0 mgPt cm−2 anode and non-PGM catalyst cathode can reach 124.5 mW cm−2 at 80 °C and 58.6 mW cm−2 at 50 °C, while the highest selectivity of C3 acids (glyceric acid + tartronic acid) can reach 91%. The study found that higher pH reaction media could enhance fuel cell output power density (electricity generation) and selectivity of C3 acids, while lower glycerol concentration could improve the selectivity of deeper-oxidized products (mesoxalic acid and oxalic acid). The fuel cell reactor with the Pt/C anode catalyst demonstrated an excellent reusability, and successfully obtained tartronic acid with a selectivity of 50% and mesoxalic acid with a selectivity of 7%, which are high compared to heterogeneous catalytic glycerol oxidation in batch reactors. It is found that the anode overpotential can regulate the oxidation product distribution, and that higher anode overpotentials favor C C bond breaking, thus lowering the C3 acids selectivity. The reaction sequence of glycerol electro-oxidation detected in an electrolysis half cell with an on-line sample collection and off-line HPLC analysis agrees with the results obtained from single fuel cell tests. However, inconsistencies between the two systems still exist and are possibly due to different reaction environments, such as electrode structure, glycerol:catalyst ratio, and residence time of reactants.

The liquid-phase oxidation of glycerol has been studied on gold nanoparticles supported on different carbon materials: activated carbon (AC), graphite (G) and carbon ribbon-type nanofibers (CNF-R). Catalysts were prepared by two different methods: impregnation (-IMP) and gold-sol (-SGT). The influence of the operating conditions (e.g. pressure, temperature, NaOH/glycerol molar ratio and glycerol/Au molar ratio) on the catalytic activity and product selectivity was studied in detail. The oxygen pressure was found to have a very small influence on the reaction rates, with the reaction being zero order with respect to oxygen. The selectivity to glyceric acid was significantly enhanced on increasing both the oxygen pressure and reaction temperature, which simultaneously led to a decrease in both glycolic and tartronic acid selectivities. Glycerol conversion and glyceric acid selectivity increased on increasing the NaOH/glycerol molar ratio in the range from 1 to 2. At higher values of this molar ratio, these two parameters remained approximately constant. A linear correlation was observed between glycerol conversion and the amount of catalyst (up to 0.5 g) and this indicates that the reaction was kinetically controlled. However, along with the increase in the catalytic activity with the amount of catalyst, a substantial decrease in the selectivity to glyceric acid was also observed. Finally, a kinetic model to describe the reaction mechanism was proposed and good agreement between the experimental and predicted values was achieved.

Glycerol was oxidized catalytically under aerobic conditions in the presence of monometallic nanoclusters of gold on poly(1-vinylpyrrolidin-2-one) (PVP) to give hydroxymalonic acid (tartronic acid) as the major product, together with 2,3-dihydroxypropanoic acid (glyceric acid) and hydroxyacetic acid (glycolic acid) as minor products. In contrast, oxalic acid was selectively obtained when bimetallic Au–Pd:PVP nanoclusters were used as the catalyst.

Glycerol has the potential of being a low-cost and extremely versatile building block. However, current transformation strategies such based on noble-metal-catalysts show several disadvantages including catalyst deactivation or negative environmental impacts. In this study glycerol was oxidized by 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) in the presence of laccase from Trametes hirsuta. Analysis of the reaction production indicated sequential oxidation to glyceraldehyde, glyceric acid and tartronic acid, finally resulting in mesoxalic acid. The number and nature of oxidation products was depended on the concentration of TEMPO used. At lower TEMPO concentrations (

Monometallic and bimetallic catalysts based on Au and Pt metal supported on carbon, were synthesized by varying the nature of Pt precursor and the reducing agent. It was found that the nature of Pt precursor in combination with reducing agent, significantly affected the process of reduction and particle growth. The catalytic performance of the synthesized Pt/C catalysts in the liquid phase oxidation of glycerol was considerably affected in terms of activity and distribution of products. Reduction by H2 and NaBH4 depending on the nature of the Pt precursor resulted in the most active and selective catalysts. Improvement of activity was found by addition of Au. © 2006 Elsevier B.V. All rights reserved.

The side products formed in the TEMPO-mediated oxidation of glucose to glucaric acid were determined by GC. Next to glucaric acid, gluconic acid, the intermediate in the oxidation, the degradation products, oxalic acid, tartronic acid, meso- (erythraric) and DL-threaric (tartaric) acid were detected. Chiral GC determined the DL-tartaric acid to be non-racemic mixtures of L- and D-tartaric acids, with inverse D/L-ratios depending on the oxidation of D- or L-glucose. The origin of all degradation products is rationalized. This study details a fast screening method to optimize the reaction conditions toward minimal degradation.

A novel Cerium(IV) mediated oxygenation of dialkyl malonates leading to a direct synthesis of tartronic acid derivatives is described.

An operational electrolyte system was developed for the isotachophoretic separation of fifteen rare-earth elements (yttrium and lanthanides except for Pm) by adding a helping complexing agent to an α-hydroxyisobutyric acid (HIBA) electrolyte system. As a result of testing several helping agents such as malonic acid, malic acid, tartronic acid and glycolic acid, the optimized leading electrolyte was a 20-m M ammonia solution containing 2 m M malonic acid and 7.5 m M HIBA (pH 4.8, 2-ethylbutyric acid buffer). The terminator was a 20-m M carnitine hydrochloride. According to the stability constants of rare-earth–malonate complexes evaluated by isotachophoretic method, the successful separation was due to the smaller stability constants of Y–malonate complexes compared with those of the medium lanthanide elements to be separated.

Experiments of the influence of mesoxalic and tartronic acid on the oscillatory behavior and on the spiral tip motion in a ferroin-catalyzed Belousov-Zhabotinsky (BZ) solution are reported. The oscillations were observed in batch and CSTR systems, and for the investigations of the spiral tip motion an open gel reactor was used. A characteristic shoulder in the oscillations is associated with an additional Br− production phase. The chemical parameters for a transition from a hypocycloidal to a circular tip trajectory are found. The findings are compared with the temporal and spatial dynamic behavior, occurring during the ageing process of the solution.

A CoA-thioester dependent transferase, hydroxycinnamoyl-CoA: tartronate hydroxycinnamoyltransferase, involved in the formation of hydroxycinnamoyltartronic acids, was extracted from young plants of mung bean and some of its properties determined. Occurrence and development of the transferase in different organs of the young plant correlated well with the accumulation patterns of the hydroxycinnamoyltartronates.

DTA and non-isothermal UV measurements of the oxidation of malonic, tartronic, glyoxylic and monobromomalonic acids by ceric sulphate in dilute aqueous sulphuric acid were evaluated using the novel one-step strategies for the determination of quantities typical of mechanism. Due to the kinetic evaluation, experiments with malonic acid reveal the expected bimolecular reaction only in definite concentration ranges. For very small ceric ion concentrations, the large resulting reaction heats suggest that ceric ion catalyzes the oxidation of malonic acid and its oxidation products, via the corresponding organic radicals and intermediate addition of molecular oxygen. If the concentration is raised, different scenarios in a rather complex mechanism are passed, which include situations of first-order, zeroth-order, autocatalytic and consecutive character with crossing-over effects. For sufficient concentration of the cerium salt, the kinetics are influenced by repetitive oxidation of malonic acid to tartronic and glyoxylic acid by the metal salt. This interpretation is in accordance both with results of experiments with tartronic acid and glyoxylic acid as well as with attempts to simulate the experimental signals approximately using a model of seven coupled reactions.

Kraft pulp and alkali-cooked cotton have been treated with hydrogen peroxide in the presence of alkali. The alditol (produced by reduction) and acid end-groups were isolated by chromatography. It is concluded that existing deoxyaldonic acid end-groups are partly destroyed and new reducing end-groups are produced, which, in turn, are degraded stepwise until the glycosidic bond is reached. Further degradation is then retarded. The presence of hexonic acid end-groups and C -(2,3-dihydroxypropyl)tartronic acid in the spent liquor obtained after treatment of hydrocellulose indicate that carbonyl groups have been introduced oxidatively.

The syntheses of anhydrosulphite and anhydrocarboxylate derivatives of tartronic acid are described. These compounds, more correctly named 5-carboxy-1,3,2-dioxathiolan-4-one-2-oxide and 5-carboxy-1,3-dioxolan-2,4-dione have been shown to undergo polymerization and copolymerization to poly-α-esters containing the tartronic acid residue, characterized by the presence of a pendant carboxyl group. Thermal polymerization of the anhydrosulphite appears to proceed in a substantially identical manner to other members of the series in which the monomer decomposes by a first order process to yield an α-lactone which polymerizes by a rapid chain growth reaction. Because the rate of thermal polymerization of tartronic acid anhydrosulphite is much more rapid than simple alkyl substituted anhydrosulphites, copolymerization favours the former residues. More successful copolymerization was achieved by the use of tertiary base initiators and the anhydrocarfaoxylate derivative of tartronic acid. The polymers and copolymers described are of potential value in the synthesis of drug-carrying biodegradable matrices or more hydrophilic analogues of poly(glycolic acid) which combine the known bioerodibility of the moiety with that presence of a pendant carboxyl group.

1. Contrary to the observations of earlier workers, it has been shown that formic acid can be quantitatively oxidixed by ceric sulphate in the presence of concentrated sulphuric acid. 2. Tartaric, malonic, malic and glycolic acids can also be oxidized completely to carbon dioxide and water by the following general procedure : to a known amount of the organic acid is added ceric sulphate (excess) solution in dilute sulphuric acid and the mixed solution refluxed for ten to fifteen minutes. Concentrated sulphuric acid (double the volume of the reaction mixture) is then added taking care that formic acid is not lost during the addition, and the mixture again refluxed for 45 to 50 minutes. The excess ceric sulphate is determined by titrating against ferrous ammonium sulphate. 3. The complete oxidation of the above acids provides satisfactory methods for their quantitative estimation.

A method for the isolation, identification, and quantitative estimation of tartronic acid in plant and animal tissues, and in urine is described. Using this method of identification and analysis the tartronic acid content of some urines and various plant and animal tissues has been determined, and the results compared with values previously reported by others. A report in the literature that tartronate is not metabolized by the rat has been confirmed.

A new method for the microdetermination of acetoin and tartronic acid was described. This was done by an oxidation-reduction reaction. Oxidation of acetoin and tartronic acid were effected by means of an excess of Cu(III) solution on heating, the remaining excess of Cu(III) was titrated back by acidifying and adding a known excess of arseneous oxide solution against a standard iodine solution with the use of starch as an indicator.