- Synthesis and intrinsic blue fluorescence study of hyperbranched poly(ester-amide-ether)
-
A series of hyperbranched poly(ester-amide-ether)s (H-PEAEs) were synthesized via the A2+CB3 approach by the self-transesterification of ethyl ester-amide-ethers end-capped with three hydroxyl groups and ethyl ester group at two terminals. The molecular structures were characterized with 1H NMR and FT-IR spectroscopy. The number average molecular weights were estimated by GPC analysis to possess bimodal wide distribution from 1.57 to 2.09. The strong inherent blue fluorescence was observed at 330 nm for excitation and 390 nm for emission. Moreover, the emission intensity and fluorescence quantum yield increased along with the incorporated ether chain length, as well as almost linearly with the H-PEAE concentration in an aqueous solution. For comparing the fluorescence performance, the linear poly(ester-amide-ether) (L-PEAE) and hyperbranched poly(ester-amide) (H-PEA) were synthesized. The results showed that the coexistence of ether bond and carboxyl group in the molecular chain was essential for generating the strong fluorescence. However, the compact backbone of H-PEAE would be propitious to the enhancement of fluorescence properties.
- Zhang, Yong,Fu, Qi,Shi, Wenfang
-
-
Read Online
- Biomass-derived dibasic acids to diesters with inorganic ligand-supported catalyst: synthesis, optimization, characterization
-
Several attempts have been made to obtain aliphatic dicarboxylic diesters from esterification reaction to develop the biomass-derived platform molecules and green manufacturing processes. In this paper, Na3(H2O)6[AlMo6O18(OH)6], an Anderson-type polyoxometalate, firstly, was reported as a catalyst for diester synthesis from dicarboxylic acid to diester which showed an well productivity and selectivity characterized by 1H and 13C. Response surface methodology (RSM) integrated with the desirability function approach was used to determine the best operative conditions, and the optimal reaction parameters for maximum dipropyl succinate yield (77 ± 2.5%) were identified as 1.19?mol.% catalyst loading, 4.9:1 propanol/succinic acid ratio, 113?°C, and 9.6?h. Three batches of tests were carried for catalyst recycling with 78–75% yield even after 6 cycles of esterification. In addition, the substrate carbon chain was increased for investigation of substrate scope achieving satisfactory results and all products were characterized by 1H and 13C nuclear magnetic resonance spectroscopy.
- Chen, Zhe,Han, Sheng,Lu, Deli,Xu, Yumeng
-
-
- The synthesis of di-carboxylate esters using continuous flow vortex fluidics
-
A vortex fluidic device (VFD) is effective in mediating the synthesis of di-esters at room temperature. Processing under ambient conditions allows for a simple and efficient synthesis, whilst operating under continuous flow addresses scalability. The rotational speed of the sample tube and the flow rate were critical variables during reaction optimization, and this relates to the behaviour of the fluid flow at a molecular level. Whilst at specific rotational speeds the tube imparts a vibrational response into the fluid flow, the flow rate dictates residence time and the ability to maintain high levels of shear stress. The combination of mechanically induced vibrations, rapid micromixing, high levels of shear stress and water evaporation results in yields up to 90% for 3.25 minutes or less residence time. These results are key for devising greener and more efficient processes both mediated by the VFD and other continuous flow platforms.
- Britton, Joshua,Dalziel, Stuart B.,Raston, Colin L.
-
p. 2193 - 2200
(2016/04/19)
-
- METHOD FOR CONTINUOUSLY PREPARING CARBOXYLIC ACID ESTER
-
A method for continuously preparing a carboxylic acid ester is disclosed. In the method of the present invention, a vertical reactor is filled with a solid catalyst, a carboxylic acid and an alcohol are introduced into a lower part of the vertical reactor, esterification is performed to form an esterized mixture, the esterized mixture is output from an upper part of the vertical reactor, and distillation is performed to isolate the carboxylic acid ester. The method of the present invention is simple, easily controlled and environmental friendly, and has significantly high conversion rate and selectivity.
- -
-
Paragraph 0030; 0034
(2013/11/19)
-
- Synthesis of fluorescent carboxylic acid ligands for construction of monolayers on nanostructures
-
Two new long-chain carboxylic acids (1, 2) bearing strong fluorescent group pyrene as ligands for Self-Assembled Monolayers (SAMs) have been synthesized. The multistep targeted synthesis is accomplished by use of Pyren-1-yl methylamine hydrochloride and employing simplified synthetic protocols. Compound 2 contains a chiral center purposely introduced along the atom chain in order to make it suitable for chiro-optical studies of the resulting SAMs.
- Jadhav, Sushilkumar A.
-
p. 1640 - 1646,7
(2020/09/09)
-
- Influence of positional isomers on the macroscale and nanoscale architectures of aggregates of racemic hydroxyoctadecanoic acids in their molecular gel, dispersion, and solid states
-
Inter/intramolecular hydrogen bonding of a series of hydroxystearic acids (HSAs) are investigated. Self-assembly of molecular gels obtained from these fatty acids with isomeric hydroxyl groups is influenced by the position of the secondary hydroxyl group. 2-Hydroxystearic acid (2HSA) does not form a molecular dimer, as indicated by FT-IR, and growth along the secondary axis is inhibited because the secondary hydroxyl group is unable to form intermolecular H-bonds. As well, the XRD long spacing is shorter than the dimer length of hydroxystearic acid. 3-Hydroxystearic acid (3HSA) forms an acyclic dimer, and the hydroxyl groups are unable to hydrogen bond, preventing the crystal structure from growing along the secondary axis. Finally, isomers 6HSA, 8HSA, 10HSA, 12HSA, and 14HSA have similar XRD and FT-IR patterns, suggesting that these molecules all self-assemble in a similar fashion. The monomers form a carboxylic cyclic dimer, and the secondary hydroxyl group promotes growth along the secondary axis.
- Abraham, Shibu,Lan, Yaqi,Lam, Ricky S. H.,Grahame, Douglas A. S.,Kim, Jennifer Jae Hee,Weiss, Richard G.,Rogers, Michael A.
-
experimental part
p. 4955 - 4964
(2012/07/13)
-
- One-pot synthesis of cyclophane-type macrocycles using manganese(iii)- mediated oxidative radical cyclization
-
Cyclophane-type macrocyclic compounds from 21 to 56 members having two fused dihydrofuran rings were synthesized by the manganese(iii)-mediated oxidation of terminal dienes with bis(3-oxobutanoate)s containing aromatics. The reaction detail, characterization and reaction pathways are described. The Royal Society of Chemistry 2011.
- Ito, Yosuke,Tomiyasu, Yuichi,Kawanabe, Takahiro,Uemura, Keisuke,Ushimizu, Yuu,Nishino, Hiroshi
-
supporting information; scheme or table
p. 1491 - 1507
(2011/04/23)
-
- SKIN EXTERNAL PREPARATIONS AND COSMETICS
-
An object of the present invention is to provide skin external preparations and cosmetics which contain a branched acyl carnitine and have excellent formulation stability. A skin external preparation of the present invention includes a carnitine derivative represented by the following Formula (1) and/or a carnitine derivative salt represented by the following Formula (2), and an amphoteric surfactant. In Formula (1), R1 and R2 are each independently a C1-18 optionally branched, saturated or unsaturated aliphatic hydrocarbon group. In Formula (2), R1 and R2 are the same as in Formula (1), X? is a specific anion and Y+ is a specific cation.
- -
-
-
- Lip treatment composition
-
A lip-treatment composition for topical application to the lips comprising a base comprising oil, water and a structurant, and at least one active component active with regard to the lips, gums, teeth, throat, or oral mucosa.
- -
-
-
- Cosmetic composition
-
A composition suitable for topical application to mammalian skin or hair for inducing, maintaining or increasing hair growth comprises: (i) a first chemical inhibitor chosen from proteoglycanase inhibitors, glycosaminoglycanase inhibitors, glycosaminoglycan chain cellular uptake inhibitors or mixtures thereof; and (ii) a cosmetically acceptable vehicle for the chemical inhibitor; provided that when the first chemical inhibitor is a weak inhibitor, such that a 1 mM aqueous solution of the inhibitor reduces proteoglycanase activity, glycosaminoglycanase activity or cellular uptake of glycosaminoglycan chains, by from 5 to 50%, in accordance with at least one of the assay tests as herein described, then there is also present in the composition a second chemical inhibitor and/or an activity enhancer. When minoxidil is the sole chemical inhibitor, then the activity enhancer is a penetration enhancer chosen from a limited number of materials, including certain esters and cationic polymers. The total amount of chemical inhibitor present in the composition is sufficient to increase hair growth in the rat, when said composition is applied topically thereto, by at least 10% more than that obtainable using a control composition from which the said inhibitors have been omitted.
- -
-
-