Langmuir–Blodgett films of indandione-l,3 pyridinium betaine. II: Molecular structure and properties of monolayers; simulation and optical absorption data

The molecular structure and optical properties of a monolayer at the air/water interface of novel amphiphilic derivatives of indandione-1,3 pyridinium betaine (IPB) with different lengths of the aliphatic tail, namely C_1lIPB and C₁₇IPB, have been studied using optical absorption techniques and computer simulation approaches. The compression π-A isotherm of the C₁₇IPB monolayer and computer simulation of its molecular structure show that there may exist two energetically stable molecular configurations, one with antiparallel orientation of the dipole moments of the C₁₇IP ‘heads’ in the low-pressure region at π = 5–32 mN m^?1 and the second (after a distinct phase transition at π = 33 mN m^?1) with parallel orientation of the dipoles, with different tilt angles and areas per molecule. For C₁₁IPB only the first structural phase is observable. The compression-induced changes in spectral characteristics of the two structural phases go in diametrically opposite directions. In the low-pressure phase compression induces a red shift and an increase in intensity of the S₁ absorption band, while in the high pressure phase a blue shift and a decrease in the intensity of this band are observed. These spectral changes correlate reproducibly with the compression π-A isotherms. Measurements of absorption dichroism confirm the change in the tilt angle at the phase transition pressure. The compression-induced spectral changes have been substantiated by the results of quantum chemical calculations.     

Determination of betaine and free amine in alkyldimethyl betaine by potentiometric titrations

Two selective analytical methods are presented for the determination of betaine and free amine contents, respectively, in commercial alkyl dimethyl betaines. Both methods are based on titrations with potentiometric end point detection. The accuracy and precision are discussed. Presented in part at the 1991 Annual AOCS Meeting in Chicago, IL.     

Alkylbetainate chlorides: Synthesis and behavior of monolayers at the air-water interface

In this study, cationic alkylbetainate chloride surfactants (C_nBC, n = 10-16) are synthesized using more environment-friendly reagents (glycine betaine, thionyl chloride and primary alcohols) than in previous works (chloroacetyl chloride, trimethylamine and primary alcohols). The interfacial behavior of the C_nBC monolayers is studied onto aqueous subphases at 20 °C using the Langmuir through technique. Different experimental conditions including pH, temperature, sodium salts and Na₂SO₄ ionic strength are investigated.The results obtained have shown that the C_nBC with a hydrocarbon chain length ≥ 14 are able to form insoluble monolayers. The C₁₆BC monolayer stability checked by the compression-expansion cycles has shown a superimposition of isotherms in the whole liquid-condensed region and an irreversible rearrangement of the molecules at high compression. The C₁₆BC monolayer is not influenced by the pH and the presence of monovalent anions but it is influenced by the temperature, the divalent anions and the ionic strength. It has exhibited a great stability whatever the experimental conditions.     

水溶性环烷基咪唑啉甜菜碱的合成及其对碳钢的缓蚀性能

目前,对水溶性环烷基咪唑啉甜菜碱的合成和应用研究不够,用环烷酸、三乙烯四胺、氯乙酸钠等原料合成后作碳钢缓蚀剂,用静态挂片失重法和电化学方法,研究了其在HCl,HCl-H2S水相体系中的缓蚀性能。结果表明：水溶性环烷基咪唑啉甜菜碱在1000mg／LHCl腐蚀体系中为以抑制阳极过程为主的阴阳极混合型缓蚀剂,在HCl,HCl...     

三乙醇胺硬脂酸酯甜菜碱柔软剂的合成及性能研究

以硬脂酸、三乙醇胺、氯乙酸为原料，在一定条件下合成了三乙醇胺脂肪酸酯甜菜碱.探讨了合成的最佳工艺条件，并对其性能进行了测试，结果表明：该柔软剂的柔软性接近氨基硅油，白度和润湿性均好于氨基硅油，该产品易生物降解，属环保型产品.     

Haplotype Analysis of BADH1 by Next-Generation Sequencing Reveals Association with Salt Tolerance in Rice during Domestication

Betaine aldehyde dehydrogenase 1 (BADH1), a paralog of the fragrance gene BADH2, is known to be associated with salt stress through the accumulation of synthesized glycine betaine (GB), which is involved in the response to abiotic stresses. Despite the unclear association between BADH1 and salt stress, we observed the responses of eight phenotypic characteristics (germination percentage (GP), germination energy (GE), germination index (GI), mean germination time (MGT), germination rate (GR), shoot length (SL), root length (RL), and total dry weight (TDW)) to salt stress during the germination stage of 475 rice accessions to investigate their association with BADH1 haplotypes. We found a total of 116 SNPs and 77 InDels in the whole BADH1 gene region, representing 39 haplotypes. Twenty-nine haplotypes representing 27 mutated alleles (two InDels and 25 SNPs) were highly (p < 0.05) associated with salt stress, including the five SNPs that have been previously reported to be associated with salt tolerance. We observed three predominant haplotypes associated with salt tolerance, Hap_2, Hap_18, and Hap_23, which were Indica specific, indicating a comparatively high number of rice accessions among the associated haplotypes. Eight plant parameters (phenotypes) also showed clear responses to salt stress, and except for MGT (mean germination time), all were positively correlated with each other. Different signatures of domestication for BADH1 were detected in cultivated rice by identifying the highest and lowest Tajima’s D values of two major cultivated ecotypes (Temperate Japonica and Indica). Our findings on these significant associations and BADH1 evolution to plant traits can be useful for future research development related to its gene expression.     

十二烷基二甲基羟丙基磺基甜菜碱的合成和性能研究

以十二胺、甲酸、甲醛、环氧氯丙烷、亚硫酸氢钠为原料,利用丙磺酸中间体法合成了两性表面活性剂十二烷基二甲基羟丙基磺基甜菜碱(HSB-12)。用红外光谱对目标产物的结构进行表征,并研究了其表面活性和复配性能。结果表明,HSB-12的水溶液在25℃的cm c=1.6 mmol/L,表面张力为25.85 mN/m,65℃时可降低油水界面张力至10-2mN/m。HSB-12与非离子表面活性剂OP-10复配产生了较好的协同效应,HSB-12与OP-10的摩尔比为3∶7,表现出最佳复配效果,此时复配体系的cm c=0.9 mmol/L,表面张力为23.85 mN/m,并可降低油水界面张力至10-3mN/m,达到了超低界面张力的水平。     

Glycine betaine improves oxidative stress tolerance and biocontrol efficacy of the antagonistic yeast Cystofilobasidium infirmominiatum

The effect of H₂O₂-induced oxidative stress on the viability of the yeast antagonist, Cystofilobasidium infirmominiatum, as well as the effect of exogenous glycine betaine (GB) on yeast viability under oxidative stress, was determined. GB treatment improved the tolerance of C. infirmominiatum to oxidative stress. Compared to untreated control yeast cells, GB-treated cells showed less accumulation of reactive oxygen species (ROS) and a lower level of protein oxidation in response to oxidative stress. Additionally, GB-treated yeast exhibited greater biocontrol activity against Penicillium expansum and a faster growth in wounds of apple fruits stored at 25 °C compared to the performance of untreated yeast. The activities of antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) of C. infirmominiatum were elevated by GB treatment. Results indicate that the elicitation of antioxidant response by GB may contribute to improvements in oxidative stress tolerance, population growth in apple wounds, and biocontrol activity of C. infirmominiatum.     

芥酸酰胺丙基甜菜碱型自转向酸流变特性研究

研究了以芥酸酰胺丙基甜菜碱黏弹性表面活性剂为主剂的自转向酸体系的流变特性。通过稳态剪切流动实验,得到鲜酸和残酸体系的本构方程分别为σ=0.0893γ^0.803（R²=0.967）、σ=6.30γ^0.383（R²=0.983）,均符合幂律型非牛顿流体;两种酸液体系黏度随着剪切速率的增加而快速降低,鲜酸在100 s^-1时的黏度平台值约为40mPa·s,残酸在400 s^-1时的黏度平台值约为150 mPa·s。触变性实验表明,低剪切速率下鲜酸体系黏度下行线大于上行线,表现为复合触变性;残酸体系触变环面积小,剪切后结构易恢复。小幅振荡实验表明,鲜酸体系储能模量（G′）总是大于损耗模量（G″）,且G′—G″曲线基本呈直线。残酸体系G″总是大于G′,在低频率下G′—G″符合Maxwell模型Cole-Cole图,表现出单一松弛时间的线性黏弹性;而在高频率下,G′—G″曲线又呈现直线趋势,显示出复杂的黏弹性。     

表面活性剂泡沫的影响因素研究

人们在使用洗涤产品时,都希望能够得到更多、更丰富的泡沫,所以泡沫的高低很大程度上可以作为衡量产品质量的主要指标。通过实验主要考察了在不同活性物浓度,不同水硬度条件和不同体系温度下,SLES、CAB和它们的复合物的泡沫性能,结果表明,SLES的泡沫性能受硬水影响不大,CAB的泡沫性能随浓度的变化而有所不同,SLES和CAB的复合物有更优秀的泡沫性能,表现出良好的协同增效性。