Pimelic Acid Research Articles

Influence of chain length, particle size, and thermal treatment of dicarboxylic acid-functionalized titanium dioxide filler in polypropylene

The influence of size and thermal treatment of titanium dioxide (TiO2) functionalized with dicarboxylic acids of different length chains on the crystallization of isotactic polypropylene (iPP) has been investigated. The functionalization and crystallization were analyzed by FTIR, DSC, XRD, and mechanical tests. The chain length is crucial, while glutaric acid favored α-nucleation, pimelic and azelaic promoted β-crystals. Pimelic acid was the best by increasing β-crystals up to 54.1% compared with pure iPP (4.7%). Regarding particle size, the smallest dimension increased β-nucleation by ~ 32%. While thermal treatment was applied, β-crystal content increased by ~ 22.7%. Regarding mechanical properties, the fillers presence decreased tensile stress and stiffness since the high content of β-crystals decrease elastic modulus. These results offer evidence that it is possible to prepare fillers able of selecting the type of crystallization since functionalized-TiO2 can promote α- or β-crystals by varying particle size, functionalization agent, and applying a thermal treatment. However, more detailed studies are needed to confirm these observations.

Engineering a heterologous synthetic pathway in Escherichia coli for efficient production of biotin.

To enhance biotin production in Escherichia coli by engineering a heterologous biotin synthetic pathway. Biotin operon genes from Pseudomonas putida, which consisted of a bioBFHCD cluster and a bioA gene, was engineered into Escherichia coli for biotin production. The introduction of bioW gene from Bacillus subtilis, encoding pimeloyl-CoA synthetase and sam2 gene from Saccharomyces cerevisiae, encoding S-adenosyl-L-methionine (SAM) synthetase contributed to the heterologous production of biotin in recombinant E. coli. Furthermore, biotin production was efficiently enhanced by optimization of the fermentation compositions, especially pimelic acid and L-methionine, the precursor related to the pimeloyl-CoA and SAM synthesis, respectively. The combination of overexpression of the heterologous biotin operon genes and enhanced supply of key intermediate pimeloyl-CoA and SAM increased biotin production in E. coli by more than 121-fold. With bioprocess engineering efforts, biotin was produced at a final titer of 92.6mg/L in a shake flask and 208.7mg/L in a fed-batch fermenter. Through introduction of heterologous biotin synthetic pathway, increasing the supply of precursor pimeloyl-CoA and cofactor SAM can significantly enhance biotin production in E. coli.

Novel Salt-Cocrystals of Berberine Hydrochloride with Aliphatic Dicarboxylic Acids: Odd-Even Alternation in Physicochemical Properties.

In this study, various structurally similar aliphatic dicarboxylic acids, namely, succinic acid, glutaric acid, adipic acid, and pimelic acid, were employed as coformers to obtain phase pure cocrystals with berberine chloride (BCl) by a slow solvent evaporation method. The structures of the four novel salt-cocrystals of BCl were determined by single crystal X-ray diffraction analysis and their solid-state properties were characterized. Compared with BCl·2H2O, all the cocrystals showed a higher melting point, improved powder dissolution and intrinsic dissolution rate (IDR), and lower hygroscopicity. It is noteworthy that the melting points and IDRs of these cocrystals exhibit an odd-even alternation with the carbon chain length of the acids.

Development and study of new oil compositions on industrial dioktylcebacylic oils adding esters of 2.5,5.5-tetrametylolcyclopethane

Complex esters of 2.5,5.5-tetrametylolcyclopethane with heptanedioic and hexanoic acids, as well as methyl and 2-ethylhexyl alcohols have been synthesized and studied. Few compositions have been obtained adding these esters to the industrial ones of 5-20 % diisooktyl sebacylic. It was defined that exploitation characteristics of these compositions are significantly higher than those of DOS: viscosity index, flash point, thermal oxidative stability and lubricating characteristics. Based on these parameters, it is recommended to use in the future these compositions in the preparation of aircraft oils of gas-turbine engines instead of DOS esters.

Use of additives to regulate solute aggregation and direct conformational polymorph nucleation of pimelic acid.

Understanding the nucleation pathway and achieving regulation to produce the desired crystals are mutually beneficial. The authors previously proposed a nucleation pathway of conformational polymorphs in which solvation and solute self-assembly could affect the result of the conformational rearrangement and further nucleation outcomes. Based on this, herein α,ω-alkanedi-carb-oxy-lic acids (DAn, where n represents the number of carbon atoms in the molecule, n = 2-6, 8-11) were designed as homologous additives to interfere with the self-assembly of pimelic acid (DA7) to further induce the form II compound, which differs from form I only in conformation. Interestingly, longer-chain additives (DA6-11) have a stronger form II-inducing ability than short-chain ones (DA2-4). In addition, an apparent gradient of the degree of interference with solute self-assembly, consistent with form II-inducing ability, was detected by infrared and nuclear magnetic resonance spectroscopy. The calculated molecular electrostatic potential charges also clearly indicate that additive-solute electrostatic interactions gradually increase with increasing carbon chain length of the additives, reaching a maximum value with DA6-11. This novel use of additives demonstrates a direct link between solute aggregation and conformational polymorph nucleation.

Novel Internal Emulsifiers for High Biocontent Sustainable Pressure Sensitive Adhesives

In this paper, two novel fully renewable internal emulsifiers have been successfully synthesized from epoxidized soybean oil and natural acids (adipic and pimelic acid) by a solvent-free and self-c...

Syntheses, Structures and Luminescence Sensing Properties of Two Cd(II) MOFs Constructed from Mixed Ligands

Hydrothermally reaction of Cd(NO3)2·4H2O, pimelic acid (H2Pim) mixed with two N-containing ligands of 1,2-bis(2-methyl-imidazol-1-ylmethyl)benzene (1,2-mbix) or 1,3-bis(2-methyl-imidazol-1-ylmethyl)benzene (1,3-mbix) gave rise to two new Cd(II) MOFs, [Cd(Pim)(1,2-mbix)] (1) and [Cd(Pim)(1,3-mbix)]·H2O (2). Both MOFs were structurally characterized by IR and UV–Vis spectra, single-crystal and powder X-ray diffraction, thermogravimetric analyses. MOF 1 shows a fourfold interpenetrating dia network. Differently, MOF 2 shows a 2D → 3D interdigitated architecture base on the 63 hcb layer when 1,2-mbix was replaced by 1,3-mbix. The luminescent properties of 1 and 2 have been investigated. Furthermore, the luminescent quenching experiments suggest both MOFs exhibit good selectivity and sensitivity to detect Fe3+ and Cr2O72− in water.

\u03b1-proteobacteria synthesize biotin precursor pimeloyl-ACP using BioZ 3-ketoacyl-ACP synthase and lysine catabolism

Pimelic acid, a seven carbon α,ω-dicarboxylic acid (heptanedioic acid), is known to provide seven of the ten biotin carbon atoms including all those of the valeryl side chain. Distinct pimelate synthesis pathways were recently elucidated in Escherichia coli and Bacillus subtilis where fatty acid synthesis plus dedicated biotin enzymes produce the pimelate moiety. In contrast, the α-proteobacteria which include important plant and mammalian pathogens plus plant symbionts, lack all of the known pimelate synthesis genes and instead encode bioZ genes. Here we report a pathway in which BioZ proteins catalyze a 3-ketoacyl-acyl carrier protein (ACP) synthase III-like reaction to produce pimeloyl-ACP with five of the seven pimelate carbon atoms being derived from glutaryl-CoA, an intermediate in lysine degradation. Agrobacterium tumefaciens strains either deleted for bioZ or which encode a BioZ active site mutant are biotin auxotrophs, as are strains defective in CaiB which catalyzes glutaryl-CoA synthesis from glutarate and succinyl-CoA.

Bisthioureas of pimelic acid and 4-methylsalicylic acid derivatives as selective inhibitors of tissue-nonspecific alkaline phosphatase (TNAP) and intestinal alkaline phosphatase (IAP): Synthesis and molecular docking studies

Alkaline phosphatases (ALPs) are membrane bound metalloenzymes, distributed all over the body. Recent studies have revealed that by targeting ALPs can lead towards the treatment of many deadliest diseases including cardiac, cancerous and brain diseases. Thioureas and their derivatives are of considerable significance and are privileged scaffolds in medicinal chemistry. They show a wide range of pharmacological activities such as antibacterial, antiparasitic, anti-inflammatory and antioxidants etc. On the other hand, salicylic acid and its derivatives are known for its broad spectrum of activities. The work presented comprises of synthesis of N-acyl-N'-aryl substituted bisthioureas of pimelic acid (1–7) and 3,5-dimethyl pyrazole (11), 1-aroyl-3-aryl thiourea (12) and 1,3,4-oxadiazole (13) derivatives of 4-methyl salicylic acid. Structures of all the synthesized compounds were characterized by FT-IR and 1H NMR spectroscopic analysis. Synthesized compounds were evaluated for their alkaline phosphatases inhibition potential and exhibited high potency as well as selectivity towards h-TNAP and h-IAP. Compound 7 and 12 which were the bisthiourea derivative of pimmelic acid and thiourea derivative of 4-methyl salicylic acid, respectively, showed excellent selectivity against h-TNAP and h-IAP, respectively.

Ferroelasticity with a Biased Hysteresis Loop in a Co-Crystal of Pimelic Acid and 1,2-Di(4-pyridyl)ethane

Formation of two-component supramolecular polymers can lead to high supramolecular designability by combination of different kinds of components in addition to development of thermal and physical p...

Co-Amorphous Telmisartan-Pimelic Acid with Improved Solubility

Telmisartan (TEL), a type of antihypertensive drug, has poor solubility. To improve its solubility, the co-amorphous telmisartan with pimelic acid (PA) in molar ratio of 1:1 and 2:1, respectively, were obtained using a liquid-assisted grinding method. The co-amorphous system was characterized by the powder X-ray diffraction and differential scanning calorimetry. The molecular interactions of the co-amorphous were studied by the infrared spectra. After the formation of co-amorphous, the solubility of TELwas much improved, and the apparent solubility values were approximately 9-15 times as high as that of crystalline TEL. Moreover, the co-amorphous TEL-PA was stored under 25 °C/20% RH for a month without any evidence of conversion by powder X-ray diffraction analysis.

Supramolecular structure of polypropylene fibers formed with addition of functionalized graphene oxide

Pimelic acid and calcium hydroxide were used to attach calcium pimelate to the surface of graphene oxide. The additive was mixed with isotactic polypropylene granulate. Neat polypropylene and polypropylene with functionalized graphene oxide was extruded into fibers under laboratory conditions. The gravity spun fibers containing different concentration of the additive and the fibers taken at various velocities were obtained. Morphology and elemental composition of functionalized graphene oxide were studied by means of scanning electron microscopy and energy dispersive X-ray spectroscopy. The structure of fibers was examined by means of differential scanning calorimetry and wide-angle X-ray scattering. The ability of calcium pimelate supported on the surface of the graphene oxide to nucleate the β-form of polypropylene was revealed. A considerable amount of the β-form crystals was obtained in the gravity spun fibers. In the fibers taken at moderate and higher velocities the β-form disappeared. The structure of the fibers extruded with the additive was similar to the structure of the fibers extruded from neat polypropylene. At moderate velocities, the content of mesophase in the structure was high. At higher velocities, the crystalline structure built only from α-form crystals was obtained. The paper presents a discussion of the changes observed in the fiber structure in connection with polypropylene nucleation.

PH- and Temperature-Dependent Kinetics of the Oxidation Reactions of OH with Succinic and Pimelic Acid in Aqueous Solution

Rate constants for the aqueous-phase reactions of the hydroxyl radical with the dicarboxylic acids, succinic acid and pimelic acid were determined using the relative rate technique over the temperature range 287 K ≤ T ≤ 318 K and at pH = 2.0, 4.6 or 4.9 and 8.0. OH radicals were generated by H2O2 laser flash photolysis while thiocyanate was used as a competitor. The pH values were adjusted to obtain the different speciation of the dicarboxylic acids. The following Arrhenius expressions were determined (in units of L mol−1 s−1): succinic acid, k(T, AH2) (2.1 ± 0.1) × 1010 exp[(−1530 ± 250 K)/T], k(T, AH−) (1.8 ± 0.1) × 1010 exp[(−1070 ± 370 K)/T], k(T, A2−) (2.9 ± 0.2) × 1011 exp[(−1830 ± 350 K)/T] and pimelic acid, k(T, AH2) (7.3 ± 0.2) × 1010 exp[(−1040 ± 140 K)/T], k(T, AH−) (1.8 ± 0.1) × 1011 exp[(−1200 ± 240 K)/T], k(T, A2−) (1.4 ± 0.1) × 1012 exp[(−1830 ± 110 K)/T]. A general OH radical reactivity trend for dicarboxylic acids was found as k(AH2) < k(AH−) < k(A2−). By using the pH and temperature dependent rate constants, source and sinking processes in the tropospheric aqueous phase can be described precisely.

Volatility parameters of secondary organic aerosol components determined using a thermal denuder

In this study, the characterization of a new thermal denuder and its application to determine the volatility parameters of important components of secondary organic aerosol (SOA) are presented in detail. The temperature ramping rate to achieve a set value was ~14.3 °C min−1 in the range of 25–150 °C. Particle loss during the penetration through the denuder was negligible in the temperature and effective residence time (RT) ranges of 25 °C–60 °C and 12.5 s–50 s, respectively. In addition, a vapor-phase aerosol reached equilibrium with the gas phase at an effective RT of approximately 24 s. Furthermore, volatility profile data generated using the thermal denuder with the help of a scanning particle sizer were used to determine the saturation pressure (P0sat) at 25 °C and enthalpy of vaporization (ΔHv) of typical biogenic and anthropogenic SOA components by the integrated volume method. Determined ΔHv and P0sat values for succinic acid, adipic acid, pimelic acid, phthalic acid, pinic acid, and ketopinic acid were 86.6 ± 2.5 kJ mol−1, 146.1 kJ mol−1, 139.2 kJ mol−1, 135.9 kJ mol−1, 93.8 ± 1.8 kJ mol−1, and 136.6 kJ mol−1 and 4.70 ± 0.7 x 10−5 Pa, 1.98 x 10−5 Pa, 8.91 x 10−5 Pa, 8.50 x 10−5 Pa, 1.61 ± 0.5 x 10−4 Pa, and 5.81 x 10−5 Pa, respectively. These values were comparable with the literature data.

Glucose challenge metabolomics implicates the change of organic acid profiles in hyperlipidemic subjects.

Hyperlipidemia (HLP) is a major risk factor of diabetes and cardiovascular disease. Here, we applied gas chromatography-mass spectrometry to study differences in postprandial organic acid profiles in healthy and HLP subjects. In fasting status, six intermediates of the tricarboxylic acid cycle showed significant differences in HLP and healthy controls (P < 0.05). The percentage changes of 17 metabolites including three intermediates of the tricarboxylic acid cycle were significantly different during the oral glucose tolerance test. Postprandial changes in ethylmalonic acid and pimelic acid were negatively associated with HOMA-IR (homeostasis model assessment of insulin resistance; all P < 0.05) in the HLP group. Postprandial metabolism of organic acid profiles revealed energy metabolism perturbations in HLP. Our findings provide new insights into the complex physiological regulation of HLP postprandial metabolism.

Effect of aliphatic chain in dicarboxylic acids on non-isothermal crystallization and mechanical behavior of titanium dioxide/iPP composites

Non-isothermal crystallization kinetics of isotactic polypropylene (iPP) and its composites prepared with functionalized titanium dioxide (TiO2) were investigated by varying both heating rate and dosage of functionalized particles. Jeziorny’s and Mo’s methods were used to describe the non-isothermal crystallization process. The behavior of crystallization activation energy as a function of the crystallinity degree was evaluated by applying an isoconversional method. The modification of the TiO2 surface was done by testing three different carboxylic acids: glutaric, pimelic and azelaic acid and these particles were tested at different concentrations in iPP, 0.1, 0.5 and 1 % w/w; which had a high effect on the crystallization process of the polymer matrix. It was demonstrated the efficiency of the dry basis chemical reaction as a method to modify with dicarboxylic acids the surface of TiO2 particles. Such organic coatings chemically bonded to the surface of the TiO2 promoted a better incorporation of the iPP chains during crystallization and there is a clear effect of the length of dicarboxylic acids since the acids with more carbons, pimelic and azelaic, decreased the time to reach the crystalline state. Besides, the values of Young’s modulus were modified by functionalized TiO2 particles, being the acid with the longest chain (azelaic acid) the one that more increased this parameter.

Interfacial crystals morphology modification in cellulose fiber/polypropylene composite by mechanochemical method

The insufficient interfacial bonding and low toughness of cellulosic fiber reinforced polypropylene (PP) composite remain limitations for advanced applications of the composite. Here we proposed to promote the interfacial adhesion by modifying the interfacial matrix crystal type and morphology, inducing the small β -PP spherulite from the dominated α-PP. Specifically, cellulose fiber was subjected to mechanical milling to improve the accessibility of hydroxyl groups, then pimelic acid, calcium carbonate and activated cellulose particles were mechanochemically reacted during solvent-free ball milling condition to prepare cellulose fillers with β nucleating sites for PP reinforcement. The nucleating effect and tensile properties of the composite were investigated. The results showed that the modified particles were effective for producing a large percentage of β crystals with smaller and more uniform spherulite, and the induced β phase crystal increased the tensile strength and elongation at break of the composite.

Synthesis and Adsorption Study of some Chitosan Acid Derivatives as Dispersants for Ceramic Alumina Powders

The different functionality nature of Chitosan adds to its application as a preferable natural polymer not only for the recovery, separation, and concentration of metal ions, but for the fabrication of a wide spectrum of efficient materials, and opens a new window to act as a dispersant for ceramic particles in an aqueous medium; this is why the current study focused on getting Chitosan from chitin extracted from shrimp shells by known and modified chemical methods to obtain a high Degree of Deacetylation (DD) reached 93% to increase its solubility in dilute acidic aqueous medium. Three acid Chitosan derivatives were synthesized by grafting Chitosan chains with Glutaric, Pimelic, and Sebacic acids. The grafting process was checked by FTIR, which confirmed the compositions of the acid derivatives prepared as well as Chitosan... The ability of Chitosan and its derivatives to act as a dispersant for alumina ceramics powder was assessed by sedimentation and rheological techniques. The results showed that they have good power for deflocculating alumina particles, this implies that they may be good dispersant for ceramic processing in aqueous media which is the priority for ceramic manufacturers. The quantity of adsorbed dispersants, qe (mg/g), was determined by thermal gravimetric analysis, and hence the remaining concentration in equilibrium Ce (mg/L), four different types of adsorption isotherm models were determined and evaluated by calculating the variables and constants for each type and studying the behavior of polymers prepared toward each model. The S-shape curve was obtained from plotting qe vs Ce referring to that the adsorption follows BET isotherm of multi-layer where each layer obeys Langmuir-Freundlich isotherm.

Chemical modification of titanium dioxide nanoparticles with dicarboxylic acids to mediate the UV degradation in polyethylene films

This work deals with the study of the degradation of films made of low-density polyethylene (LDPE) by the incorporation of commercial titanium dioxide nanoparticles (TiO2 Nps). These nanoparticles were functionalized with three types of dicarboxylic acid, which have different length chain (glutaric, pimelic and azelaic acids), to improve their compatibility with LDPE. Besides, the effect of the functionalized TiO2 Nps concentration on the photodegradation, roughness, mechanical and thermal stability of the nanocomposites was evaluated. The obtained results show that the organic coating helps to passivate the photodegradation of LDPE; the longer carbon chain of the dicarboxylic acid, the higher active sites on filler/polymer interface, which inhibits photodegradation. Also, it was elucidated that calcium, from the functionalization, increased the thermal stability of the polymer nanocomposites when exposed to UV radiation. The thermal, physical (surface wear) and aesthetic (color) properties of polyethylene, with the functionalized nanoparticles, were less affected when exposed to the weather, where it is attributed to the UV photo-stabilization of the polymer. The resultant materials (LDPE with functionalized TiO2 Nps) can be used in diverse applications such as films for greenhouse and other agricultural applications, outdoor appliances (furniture and decks, for example), among others.

Study of four new Cd(II) metal-organic frameworks: Syntheses, structures, and highly selective sensing for 4-nitrophenol

Four new mixed ligand based metal-organic frameworks (MOFs), devised as [Cd(AA)(bpa)(OH2)]n (MOF-AA), [Cd(PA)(bpa)]n (MOF-PA), {[Cd(SUA)(bpa)].CH3OH}n (MOF-SUA) and {[Cd(AzA)(bpa)].2CH3OH}n (MOF-AzA) (where, AA = adipic acid; PA = pimelic acid; SUA = suberic acid; AzA = azelaic acid; bpa = 1,2-bis(4-pyridyl)ethane) have been synthesized, and successfully identified by elemental analyses, FT-IR, powder X-ray diffraction, single-crystal X-ray diffraction, and thermal analyses. MOF-AA exhibits 3D coordination network with new honey comb topology (4-c, uninodal net), while MOF-PA shows 2D structure with hxl/Shubnikov plane net topology (6-c, uninodal net). MOF-SUA and MOF-AzA display 2D frameworks with sql/Shubnikov tetragonal plane net topology (4-c, uninodal net). The luminescence studies affirm that the emissions from MOFs owing to π-electron rich ligand establish charge transfer transitions (n–π* and π–π*). MOF-AA has attractive luminescent property, and exhibits distinguished applications for the selective as well as sensitive detection of 4-nitrophenol.