Oxalate

According to green chemistry recommendations, avoiding usage of solvents during chemical reactions was considered as a modern approach in research worldwide. Usage of solvents usually associated with environmental impacts and chemical contamination besides the economical factor. So, it is highly recommended to undergo the chemical reaction without using solvents. Accordingly, our present study aimed to prepare carboxylate salts under solvent-free conditions. In this study, twelve salts like salicylate, oxalate, tartrate, and citrate have been prepared successfully in the form of sodium, potassium, and calcium salts using grindstone neutralization reactions between reactants in solid phase. Reactions under investigations were examined and evaluated in terms of initiating grinding time, practical percentage yield (%), and the released reaction temperature as-well-as the violence of the reaction. The reaction was affected greatly by acidity, basicity, and aromaticity of the reactants. It was found that sodium, potassium, and calcium salts of oxalate, tartrate, and citrate easily prepared within shorter time period (~ 1-4 min.) with relatively high practical percentage yield (~ 60-85 %). The violence of the reactions was monitored by recording the maximum elevated temperature which reached to 103 ᵒC after 2 min. for the reaction of tartaric acid with NaOH. Aluminum salts of salicylate, oxalate, tartrate, and citrate were excluded from the grindstone neutralization reactions due to insufficient chemical reactivity of aluminum hydroxide towards carboxylic acids. It was found that salicylic acid is the lowest reactive compound due to its aromatic property, and therefore salicylate salts show the lowest percentage yield (~ 50-70 %). Acidity and basicity are the main operational factors affecting on the chemical structure of the final product and its amount. The rate of changing temperature with grinding time (∆∅,ᵒC/min.) was calculated for the investigated reactions, and the reaction of citric acid with NaOH has the highest ∆∅ value. Finally, the proposed chemical reaction is considered as good new water resources as-well-as simple preparation method for carboxylate salts. Grindstone neutralization reactions were characterized by simplicity, workability, applicability, efficiently in addition to shorter life time for the preparation of various salts of organic acids.

The occurrence and distribution of calcium oxalate crystals were investigated in the young and ageing structures of Musa L. cultivars. The calcium oxalate crystals were tested histochemically and examined using light microscopy. The studies revealed the presence of varying forms of the crystals including intra-amylar, solitary and raphide bundles in the different tissues and organs. Remobilization and redistribution of the crystals were observed following senescence in all the cultivars investigated. The usefulness of these observations in understanding the functions and fate of calcium oxalate crystals in plants are highlighted. Crystals of calcium are among various ergastic chemical substances found in plants. These crystals have been variously reported present in storage, vegetative and reproductive organs of a number of plants. For instance, they have been found to occur in the lumina of the cells and tissues of the epidermal layer of leaves (Edeoga and Ugbo, 1997), bark and sec...

Text Background Many biological systems contain complex precipitation patterns. These structures are considered to be the result of finely tuned and genetically encoded developmental pathways. The amount of encoded information needed to generate and manipulate these structures is poorly understood. Investigating the dynamics of spontaneous pattern formation in non-biological systems provides insights to the physio-chemical phenomena that biological systems must have harnessed for living systems and that modern scientists need to understand for complex nano-technological applications. Results Here we show that highly complex, precipitation patterns similar to those found in biological systems can be formed in simple Cu(II)-oxalate systems. In these Cu(II)-oxalate systems, structures are constructed by a hierarchy of multiple processes that are precisely self-organized in space and time to form interconnected causal networks that generate complex and diverse structures dependent on co...

Oxidative stress, a well-known cause of stress-induced premature senescence (SIPS), is increased in patients with calcium oxalate (CaOx) kidney stones (KS). Oxalate and calcium oxalate monohydrate (COM) induce oxidative stress in renal tubular cells, but to our knowledge, their effect on SIPS has not yet been examined. Here, we examined whether oxalate, COM, or urine from patients with CaOx KS could induce SIPS and telomere shortening in human kidney (HK)-2 cells, a proximal tubular renal cell line. Urine from age- and sex-matched individuals without stones was used as a control. In sublethal amounts, H2O2, oxalate, COM, and urine from those with KS evoked oxidative stress in HK-2 cells, indicated by increased protein carbonyl content and decreased total antioxidant capacity, but urine from those without stones did not. The proportion of senescent HK-2 cells, as indicated by SA-βgal staining, increased after treatment with H2O2, oxalate, COM, and urine from those with KS. Expression...