Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a "one pot" suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using 13 C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems.pyruvate | citrate | Murchison meteorite | Alan Hills | interstellar nitriles

In this article, cotton is modified by m- DMDHEU and choline chloride. The modified cotton can adsorb and ion exchange ion CrO4 2- , H2AsO4 - in water solution as effectively as anionit resin. The material are activated by soaking in 24 h with mixed m-DMDHEU and choline chloride, then dried and activated in 1 h at 140 oC, all residual reactants was removed by water. Adsorption and ion exchange process were studied with a model solution contained ion CrO4 2- , H2AsO4 - in different conditions. Results showed that the modified cotton is able to adsorb ion CrO4 2- , H2AsO4 - of the model, solution is nearly completely, respectively 99,95 % and 99,60 %; the values of anionit resin is respectively 97,99 % and 97,60 % at pH=7,0.

Etherification mechanism of 4,5-dihydroxy-1,3-bis (hydroxymethyl) imidazolidin-2-one (DMDHEU) with primary alcohols in acidic and parched condition were investigated by using density functional theory combined with comparision and reference to results of experiment and spectral analysis. Geometry and energy of reactants, products, actived complexes and carbocation intermediate were optimized at B3LYP/6-311g(d,p) level. Energy level diagram is compatible with type of cation -molecule reaction. Reactants and products form actived complexes with H+ and water, in this state H+ is occupied by both alcohol and water or ether and water. This state has lower energy level compared to both of the following cases: H+ is only occupied by water; and H+ is only occupied by the product or reactant. Computational results indicate that the etherification reaction

Esterification of citric acid (CA) with the primary alcohols and the hydroxyl groups of cellulose chain (n = 1-2) in parched condition were investigated by using density functional theory (DFT) method and a two-layer ONIOM approach. Geometry and energy of reactants, products, and transition state (TS) structures were optimized at B3LYP/6-311g (d, p) level and ONIOM (B3LYP/6-311g (d, p):PM3MM) level. The computational results show that the esterification occurs in the two main steps: the first step is the dehydration reaction of CA to form anhydrides of 5-membered ring and 6-membered ring and the second step is the ring opening reaction with the hydroxyl –OH groups to form the ester products. The energy barrier of dehydration reaction step is much higher than that of ring opening reaction step. Effect of substituent R in primary alcohol R-CH2OH (R: CH=CH2, CH2NHCH3, CH2OCH3, CH2Cl) and cellulose chain (1G, 2G) on the reactivity, which has negative inductive effect –I, is significant. The combination of calculation data and experiment data were applied to make findings more rigorous. The activation energy of CA was determined by using differential scanning calorimetry (DSC) and thermal gravimetric (TG) analysis to be E a exp  = 47.8 kcal/mol; the experimental data favoured the dehydration reaction step of CA.