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Small amounts of nitrile in long chain fatty amides can be determined by separating the nitrile from the amide on a silica gel column using chloroform as the eluting solvent. The amide stays on the column. After the chloroform is removed by evaporation, the nitrile can be dissolved in a suitable solvent and determined quantitatively either by IR spectrophotometry or by TLC. Determination by IR is much faster than by TLC, but when the nitrile is present at the level of 0.1% or lower, TLC gives more satisfactory results. Technical Paper, No. 2 70, ADM Co.  相似文献   

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Five ganglioside fractions from bovine adrenal medulla were analyzed with respect to their fatty acid and long chain base compositions. The five fractions included two hematosides and three hexasamine-containing species, the latter having chromatographic properties comparable to the major gangliosides of brain. The fatty acid compositions of all five were similar: 22∶0 was the most abundant, but significant amounts of 16∶0, 18∶0, 24∶0 and 24∶1 were also present. No hydroxy fatty acids were detected. The principal long chain base in each fraction was 4-sphingenine (sphingosine), with lesser amounts of the C16 and C17 homologues. Minor quantities of the corresponding saturated bases were also detected. These were identified by two gas liquid chromatography methods: (a) trimethylsilyl ether derivatives, (b) aldehydes formed by periodate oxidation of the long chain bases. No 4-eicosasphingenine (C20-sphingosine), characteristic of brain gangliosides, was found in any of the fractions. The results demonstrate that gangliosides of the adrenal medulla show tissue specificity in fatty acid and long chain base composition which is independent of carbohydrate structure.  相似文献   

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During the manufacture of amine oxides information on the amount of unreacted tertiary amine present is needed in order to follow the reaction. A number of analytical procedures have been devised to obtain this information. Wet methods include redox titrations of the amine oxide and differential titrations using derivatization of the amine or amine oxide. Various chromatographic procedures using GC, TLC and HPLC also have been reported. All of these procedures have some limitations. A simple, rapid, quality control procedure would be useful. A rapid, nonaqueous titration procedure has been developed in our laboratory that makes use of the “anomalous salt” behavior of amine oxides. A modified solvent and titrant is used to obtain two potential breaks in the titration. The first break corresponds to half of the amine oxide. The second break represents the second half of the amine oxide plus any unreacted amine. With this information the amine oxide and unreacted amines can be calculated. The precision and accuracy of the titration have been studied using samples spiked with known amounts of amine.  相似文献   

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Yu-Yan Yeh 《Lipids》1988,23(12):1114-1118
A restricted maternal dietary intake (40% of ad libitum intake) is known to cause myelin deficit that is accompanied by decreased amounts of individual phospholipids and sphingolipids in brain myelin of suckling rats. This communication reports the effects of the same nutritional stress on the fatty acid composition of brain myelin lipids. In myelin of 19-day-old normally fed rats, palmitate (16∶0), stearate (18∶0) and oleate (18∶1) accounted for 80–90% of all fatty acids in phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine. Maternal dietary restriction resulted in deficits of total fatty acid content, but did not affect the proportional distribution of individual fatty acids among phospholipids. By contrast, longer chain (22- and 24-carbon) fatty acids accounted for more than half the fatty acid content of myelin cerebroside and sulfatide from the 19-day-old control rat pups. In undernourished rats of that age, proportions of lignocerate (24∶0) and nervonate (24∶1) in cerebroside and sulfatide were 40–50% lower than those in control rats. This, together with higher proportions of 16∶0, 18∶0 and 18∶1 and a higher ratio of C16−C20 to C22−C24 in under-nourished than in control rats, suggests an impairment in fatty acid chain elongation. Ten days of nutritional rehabilitation failed to restore the fatty acid imbalances; however, after an additional 5 days of ad libitum feeding, the experimental and control values were similar. The undernutrition results in hypomyelination, which is characterized by a proportional decrease in lignoceric and nervonic acids of sphingolipids.  相似文献   

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The addition of a series of silicon hydrides: trichlorosilane, methyldichlorosilane, dimethylchlorosilane, phenyl dichlorosilane, and methyl phenyl chlorosilane to esters of long chain unsaturated fatty acids, such as oleic, linoleic acids, and 10-undecenoic acid, was studied with respect to catalysts, temperature, and solvents. Higher yields were obtained on carrying out the hydrosilylation reactions in the presence of chloroplatinic acid or Pt on C catalysts in bulk without solvent, as compared with peroxide catalysts. The addition reaction with methyl 10-undecenoate, which has a terminal double bond, gave a higher yield than that with methyl oleate. NMR data of the products from methyl 10-undecenoate and methyl oleate, as well as their reduction products with lithium aluminum hydride, have shown that, with the former ester, the silyl moiety added exclusively to the terminal carbon atom, while, with the latter, no migration of the silyl moiety to the terminal carbon atom was observed.  相似文献   

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对甲苯磺酸掺杂聚苯胺催化合成乳酸正丁酯   总被引:3,自引:0,他引:3  
以乳酸和正丁醇为原料催化合成乳酸正丁酯,考察了原料配比、PTSA/PANI(是用对甲苯磺酸作为掺杂剂采用苯胺直接水相氧化法制备由聚苯胺(PANI)负载对甲苯磺酸的固体酸催化剂)用量、反应时间以及催化剂的重复使用等对反应的影响.确定较佳反应条件为:n(正丁醇):n(乳酸)=2.0:1、w(PTSA/PANI)=3.0%、反应温度≤130℃、反应时间3 h.结果表明,在该条件下乳酸的转化率为96.4%;催化剂经重复使用5次后,乳酸的转化率为91.8%.  相似文献   

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长链二元酸发酵技术   总被引:1,自引:0,他引:1  
介绍了目前国内外长链二元酸生产中菌种的培养与发酵,以及其发酵液中二元酸的分离与纯化技术。  相似文献   

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A series of novel side chain liquid crystal copolymers, the poly[10-(4-methoxy-4′-oxy-azobenzene) decyl methacrylate]–co-poly[2-acrylamido-2-methyl-1-propanesulfonic acid]s (10-MeOAzB/AMPS-x/y) have been synthesised by free radical copolymerisation. The mol fraction of the sulfonic acid-based group, AMPS, has been varied over a broad range of composition in the copolymers, and these have been characterised using differential scanning calorimetry (DSC), polarised light microscopy (PLM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD). The liquid crystal homopolymer and copolymers containing up to 0.54 mol fraction AMPS-based units, all exhibit a smectic A phase, while at higher mol fraction AMPS-based groups, liquid crystallinity is extinguished and the copolymers are amorphous. The local packing arrangements within the smectic A phase varies with composition attributed, in part, to phase separation between acid rich domains and liquid crystal regions. The dependence of the transitional properties on copolymer composition may be interpreted in terms of the packing efficiency of the mesogenic side chains and hydrogen bonding between the sulfonic acid groups, as a consequence of increasing the concentration of acid-based groups.  相似文献   

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一种磺酸型水性聚氨酯扩链剂的合成、表征及应用   总被引:1,自引:1,他引:1       下载免费PDF全文
王学川  任静  强涛涛 《化工学报》2015,66(2):834-842
以自制的中间体N,N-二(2-羟乙基)-2-氨基丙烯为原料,对其进行磺化反应,控制温度、时间和摩尔比反应合成磺酸型水性聚氨酯扩链剂N,N-二(2-羟乙基)-2-氨基丙磺酸钠,借助核磁氢谱(1H NMR)、红外光谱(FTIR)、元素分析、X射线衍射(XRD)等手段对合成产物进行了组成、结构和结晶性表征,用热重分析仪表征了产物的热稳定性。根据产物的磺化度确定最佳的合成工艺:反应温度为90℃,反应时间为8 h,N,N-二(2-羟乙基)-2-氨基丙烯和亚硫酸氢钠(NaHSO3)的物料比为1:2.5,磺化率可达到94%以上。分别以二羟甲基丙酸(DMPA)和自制磺酸型单体作为亲水扩链剂制备羧酸型水性聚氨酯(CWPU)和磺酸型水性聚氨酯(SWPU),其性能对比结果表明:SWPU相比于CWPU具有较好的亲水性和耐热性能;固含量及稳定性方面,SWPU也是优于CWPU的。  相似文献   

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Quantitative Differential, Thermal Analysis has been used in the wire and cable industry for determining the degree of oxidative stability of polyolefins for quality control purposes in lieu of a direct antioxidant analysis, However, it has never been shown whether the presence of each additive in a stabilizer package could be detected by this method. The results presented here indicate that the presence of a primary antioxidant and a copper inhibitor in combination can be detected separately by comparing the oxidative induction times in copper and aluminum pans. The addition of a thioester synergist such as distearyl thiodipropionate, DSTDP, is evidenced by an increased induction time in aluminum pans. However, the presence of DSTDP makes it impossible by this method to determine whether an effective level of copper inhibitor is present since the sample shows a reduced stability on copper compared to aluminum. One of two factors can be invoked to explain these results: a) DSTDP interferes with the complexing ability of the copper inhibitor or b) the copper-inhibitor complex retards the synergistic effect of the DSTDP. In either case, this factor is not important at lower temperatures since oxygen uptake data at 130°C indicate that DSTDP is an effective synergist in the presence of copper.  相似文献   

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固体枞酸定量分析方法   总被引:1,自引:1,他引:1  
分别测定了枞酸在乙醇溶液和固定在聚乙烯膜上的紫外光谱吸收特性,建立了紫外分光光度法测定固体枞酸的定量分析方法。该方法是把枞酸固定在聚乙烯膜上,选择UV波长为242 nm。给出了枞酸的定量分析方程为A=1.149x+0.6365。其精密度和稳定性的相对标准偏差分别为0.13%~0.17%和0.24%~0.62%。并与气相色谱法测定结果比较,结果指出,两者相差<2.2%。  相似文献   

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Long chain quaternary ammonium compounds are used as germicides, textile softeners and in many other industrial applications. In working with these compounds, it was found desirable to be able to determine their long chain homolog composition. Experiments were carried out attempting to perform this determination using gas chromatography. The first approach was to try and do the Hofmann degradation of the quaternaries on strongly alkaline columns used for amine determination. However, the postulated hydrocarbon peaks were not obtained. Instead, a series of peaks that represented identifiable tertiary amines emerged from the column. Using these peaks, the homolog composition of the original quaternary ammonium compound could be determined. Quaternaries containing up to 38 carbons have been identified. The types of columns and conditions used in this work are described. The quantitative relationship of the composition found was related to that of the actual composition. The apparent unequivalence of various carbon-nitrogen bondings is discussed.  相似文献   

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The bromination-dehydrobromination of trans-2-octadecenoic acid (1a) gave a mixture of rearranged products, (3a), 34.5% and (5a, 49.2%). A vicinal diol (4a), 8.7% was obtained as a minor side product. It is proposed that in the formation of 3a and 5a, the allenic intermediate 7a is involved which is derived from the expected acetylenic intermediate 6a by the usual base-catalyzed acetylene-allene rearrangement. The structures of individual reaction products were established by elemental analyses as well as by spectral studies.  相似文献   

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The reaction of 5-amino-orotic acid (H2aor) with trans-[ReOBr3(PPh3)2] in 2-propanol produced the complex [ReV(apd)Br(aor)(PPh3)2] (1, apd2  = 5-imidopyrimidine-2,4-dione). The ligand apd2  was formed by the decarboxylation of H2aor, and it is coordinated via the dinegative imido nitrogen only. The Schiff base derivative of H2aor, salicylimine-orotic acid {5-(2-hydroxy-benzylideneamino)-1,2,3,6-tetrahydro-2,6-dioxopyrimidine-4-carboxylic acid; H2sor}, was also decarboxylated in the reaction with trans-[ReOI2(OEt)(PPh3)2] in ethanol to form [ReIII(cor)I(PPh3)2]I (2, Hcor = 5-(2-hydroxybenzylideneamino)-pyrimidine-2,4(1H,3H)-dione). Decarboxylation of H2sor was not observed in its reaction with trans-[ReOCl3(PPh3)2], which led to the isolation of [ReOCl(sor)(PPh3)] (3), in which sor2  is coordinated as a tridentate ligand as expected. Spectroscopic results and the X-ray crystal structures of compounds 13 are also presented.  相似文献   

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Long chain saturated and unsaturated aldehydes, prepared by the partial reduction of the corresponding fatty acid phenyl esters with lithium tri-t-butoxyhydroaluminate, were converted quantitatively to their dimethylhydrazones. Dimethyl acetals and 1,3-dioxolanes were prepared from the dimethylhydrazones. The dimethylhydrazones were then separated from the corresponding aldehydes by gas liquid chromatography on a semipolar column. Fatty acids were readily separated quantitatively from fatty aldehydes by formation of dimethylhydrazones of the aldehydes followed by an alkaline extraction of the reaction mixture prior to gas chromatography. A method for analysis of fatty acids and aldehydes from plasmalogens is described. Presented at the AOCS Meeting, Chicago, October 1967. Michigan Agricultural Experiment Station Journal Article No. 5104.  相似文献   

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