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1.
杨丰科  王俊伟 《陕西化工》2012,(10):1803-1806
聚甲氧基二甲醚(PODE)作为柴油添加剂能够有效减少燃烧时烟尘的形成,并且具有优良的化学性质,是目前世界公认的清洁环保型燃油组分。综述了近年来国内外聚甲氧基二甲醚的合成方法及研究现状,分析总结了目前各种合成方法存在的一些问题,并展望了聚甲氧基二甲醚作为柴油添加剂的应用前景。  相似文献   

2.
以2,4-二甲氧基苯乙酸为原料,经由4步反应合成了2,4-二甲氧基甲氧基苯乙酸。对目标分子和得到的中间体进行了1H-NMR、MS表征,为合成香豆素类染料提供了新的前体化合物。  相似文献   

3.
AlCl3催化邻甲氧基苯胺与丙烯腈加成反应的研究   总被引:1,自引:1,他引:0  
报道了AlCl3催化邻甲氧基苯胺与丙烯腈发生Michael加成反应合成N-氰乙基-邻甲氧基苯胺、N,N-二氰乙基-邻甲氧基苯胺.结果表明,在60~64 ℃、10%(占邻甲氧基苯胺的摩尔百分数,以下同)无水AlCl3催化下反应12 h,生成N-氰乙基-邻甲氧基苯胺,收率88%;在80~84 ℃、60%无水AlCl3催化下反应16 h,生成N,N-二氰乙基-邻甲氧基苯胺,收率90%.用毛细管气相色谱法对合成的N-氰乙基-邻甲氧基苯胺、N,N-二氰乙基-邻甲氧基苯胺进行了含量的测定,并对其物性和结构进行了表征.  相似文献   

4.
以二甲氧基乙酸甲酯和乙酸甲酯为主要原料,经甲醇钠催化,制备药物尼伐地平中间体二甲氧基乙酰乙酸甲酯。通过考察原料摩尔比、催化剂用量、加料温度、反应温度和反应时间等因素对收率的影响,得到了最佳反应条件。二甲氧基乙酰乙酸甲酯的收率可达53.3%。  相似文献   

5.
本文以主要成分为十八碳脂肪酸甲酯的生物柴油为主要原料,以甲醇为甲氧基化试剂,在过氧化苯甲酰催化剂存在下,一步氯化法合成了氯代甲氧基脂肪酸甲酯,在反应时间为7~8h,温度为70~85℃的条件下合成的氯代甲氧基脂肪酸甲酯,探讨氯代甲氧基脂肪酸甲酯的甲氧基含量对其在PVC中增塑性能的影响。  相似文献   

6.
2—氨基—4,6—二甲氧基嘧啶的合成   总被引:3,自引:0,他引:3  
以硝酸胍和丙二酸二乙酯为原料,经环合,氯化,水解,甲氧基化合成了磺酰脲类除草剂的重要中间体2-氨基-4,6-二甲氧基嘧啶,收率93%。  相似文献   

7.
以对甲氧基苯甲醛为原料经对甲氧基苯乙腈的高压催化氢化和β-硝基对甲氧基苯乙烯的还原两种途径合成β-(对甲氧基苯)乙胺。并改进了合成中间体的某些反应条件,收率有所提高。  相似文献   

8.
研究了以对甲氧基苯乙酮为原料,经硼氢化钠还原为1-(4-甲氧基苯基)乙醇,在管式反应器中经分子筛催化裂解脱水合成对甲氧基苯乙烯的新工艺,得到优化的工艺条件:汽化温度270℃,反应温度280℃,真空度?0.09MPa,进料速度1mL/min。目标产物经红外光谱(IR)、核磁共振波谱(1H NMR)和质谱(MS)等表征。同时用色谱(GC)对产物进行了定量分析,在优化条件下对甲氧基苯乙烯纯度大于95%,收率达85%[以1-(4-甲氧基苯基)乙醇计]。该路线原料易得,反应条件温和,操作控制简便,适合进一步工业化研究。  相似文献   

9.
以没食子酸为起始原料,经甲基化、硝基化以及还原等步骤合成了3,4,5-三甲氧基苯胺,并对3,4,5-三甲氧基硝基苯还原为3,4,5-三甲氧基苯胺的合成条件进行了优化。用IR和1HNMR对各中间产物进行了表征。该路线反应收率明显提高,反应时间大幅缩短,为实现工业化生产提供了可能。  相似文献   

10.
报道了对甲氧基苯基丙酮的合成方法。由对甲氧基苯甲醛和2-氯丙酸甲酯为原料,经环合、水解和亚硫酸氢钠处理,再进行减压蒸馏获得目标产物。合成总收率80%以上,产品纯度达98%以上。  相似文献   

11.
王彦  左宁  姜媛媛  陈芳媛 《化工进展》2020,39(4):1539-1549
污泥生物炭中氮硫元素含量高,其氮硫行为和环境效应对全球气候变化的影响不容忽视。以往的研究中,研究者往往以富碳生物炭作为主要研究对象,关注碳对全球气候变化的行为和功效,而对氮硫元素的作用关注不够。本文从原始污泥基本性质到其热解过程,再到生物炭的老化,逐步对污泥生物炭整个生命周期内氮硫的行为及其环境效应研究进行综述,并对未来应注重开展的研究方向进行展望,为生物炭中氮硫元素固定、释放及与之关联的环境效应和温室气体排放控制研究提供理论基础。分析表明,污泥中氮元素含量普遍高于硫元素,且热解过程中氮比硫更容易转移至气相产物。氮硫元素随热解温度的增加,在三相产物中的分配都是炭中持续减少,油中先增后减,气中一直增加。高温(>800℃)条件下,气相中的氮含量高于固相,而硫元素则仍然主要存在于固相中。污泥生物炭老化及其环境效应研究表明,污泥生物炭氮硫元素与土壤的相互作用及其温室效应问题在今后的研究中应引起重视。  相似文献   

12.
Sandhoff disease (SD) is a glycosphingolipid (GSL) storage disease that arises from an autosomal recessive mutation in the gene for the β-subunit of β-Hexosaminidase A (Hexb gene), which catabolizes ganglioside GM2 within lysosomes. Accumulation of GM2 and asialo-GM2 (GA2) occurs primarily in the CNS, leading to neurodegeneration and brain dysfunction. We analyzed the total lipids in the brains of SD mice, cats, and humans. GM2 and GA2 were mostly undetectable in the normal mouse, cat, and human brain. The lipid abnormalities in the SD cat brain were generally intermediate to those observed in the SD mouse and the SD human brains. GM2 comprised 38, 67, and 87% of the total brain ganglioside distribution in the SD mice, cats, and humans, respectively. The ratio of GA2–GM2 was 0.93, 0.13, and 0.27 in the SD mice, cats, and humans, respectively, suggesting that the relative storage of GA2 is greater in the SD mouse than in the SD cat or human. Finally, the myelin-enriched lipids, cerebrosides and sulfatides, were significantly lower in the SD brains than in the control brains. This study is the first comparative analysis of brain lipids in mice, cats, and humans with SD and will be important for designing therapies for Sandhoff disease patients.  相似文献   

13.
By comprehensively measuring changes in metabolites in the hippocampus of stress-loaded mice, we investigated the reasons for stress vulnerability and the effect of theanine, i.e., an abundant amino acid in tea leaves, on the metabolism. Stress sensitivity was higher in senescence-accelerated mouse prone 10 (SAMP10) mice than in normal ddY mice when these mice were loaded with stress on the basis of territorial consciousness in males. Group housing was used as the low-stress condition reference. Among the statistically altered metabolites, depression-related kynurenine and excitability-related histamine were significantly higher in SAMP10 mice than in ddY mice. In contrast, carnosine, which has antidepressant-like activity, and ornithine, which has antistress effects, were significantly lower in SAMP10 mice than in ddY mice. The ingestion of theanine, an excellent antistress amino acid, modulated the levels of kynurenine, histamine, and carnosine only in the stress-loaded SAMP10 mice and not in the group-housing mice. Depression-like behavior was suppressed in mice that had ingested theanine only under stress loading. Taken together, changes in these metabolites, such as kynurenine, histamine, carnosine, and ornithine, were suggested to be associated with the stress vulnerability and depression-like behavior of stressed SAMP10 mice. It was also shown that theanine action appears in the metabolism of mice only under stress loading.  相似文献   

14.
RNA binding protein with multiple splicing (RBPMS) is expressed exclusively in retinal ganglion cells (RGCs) in the retina and can label all RGCs in normal retinas of mice, rats, guinea pigs, rabbits, cats, and monkeys, but its function in these cells is not known. As a result of the limited knowledge regarding RBPMS, we analyzed the expression of RBPMS in the retina of different mammalian species (humans, pigs, and rats), in various stages of development (neonatal and adult) and with different levels of injury (control, hypoxia, and organotypic culture or explants). In control conditions, RBPMS was localized in the RGCs somas in the ganglion cell layer, whereas in hypoxic conditions, it was localized in the RGCs dendrites in the inner plexiform layer. Such differential distributions of RBPMS occurred in all analyzed species, and in adult and neonatal retinas. Furthermore, we demonstrate RBPMS localization in the degenerating RGCs axons in the nerve fiber layer of retinal explants. This is the first evidence regarding the possible transport of RBPMS in response to physiological damage in a mammalian retina. Therefore, RBPMS should be further investigated in relation to its role in axonal and dendritic degeneration.  相似文献   

15.
Chromogranin A (CgA), B (CgB), and C (CgC), the family members of the granin glycoproteins, are associated with diabetes. These proteins are abundantly expressed in neurons, endocrine, and neuroendocrine cells. They are also present in other areas of the body. Patients with diabetic retinopathy have higher levels of CgA, CgB, and CgC in the vitreous humor. In addition, type 1 diabetic patients have high CgA and low CgB levels in the circulating blood. Plasma CgA levels are increased in patients with hypertension, coronary heart disease, and heart failure. CgA is the precursor to several functional peptides, including catestatin, vasostatin-1, vasostatin-2, pancreastatin, chromofungin, and many others. Catestatin, vasostain-1, and vasostatin-2 suppress the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in human vascular endothelial cells. Catestatin and vasostatin-1 suppress oxidized low-density lipoprotein-induced foam cell formation in human macrophages. Catestatin and vasostatin-2, but not vasostatin-1, suppress the proliferation and these three peptides suppress the migration in human vascular smooth muscles. Chronic infusion of catestatin, vasostatin-1, or vasostatin-2 suppresses the development of atherosclerosis of the aorta in apolipoprotein E-deficient mice. Catestatin, vasostatin-1, vasostatin-2, and chromofungin protect ischemia/reperfusion-induced myocardial dysfunction in rats. Since pancreastatin inhibits insulin secretion from pancreatic β-cells, and regulates glucose metabolism in liver and adipose tissues, pancreastatin inhibitor peptide-8 (PSTi8) improves insulin resistance and glucose homeostasis. Catestatin stimulates therapeutic angiogenesis in the mouse hind limb ischemia model. Gene therapy with secretoneurin, a CgC-derived peptide, stimulates postischemic neovascularization in apolipoprotein E-deficient mice and streptozotocin-induced diabetic mice, and improves diabetic neuropathy in db/db mice. Therefore, CgA is a biomarker for atherosclerosis, diabetes, hypertension, and coronary heart disease. CgA- and CgC--derived polypeptides provide the therapeutic target for atherosclerosis and ischemia-induced tissue damages. PSTi8 is useful in the treatment of diabetes.  相似文献   

16.
廖玮婷  解新安  李璐  李雁  樊荻  孙娇  王鑫 《化工进展》2019,38(5):2205-2211
通过研究木质素分别在超临界甲醇和乙醇溶剂中的液化过程,分析反应温度(260~340℃)及反应时间(0~120min)对木质素在两种溶剂中的转化率、生物油收率及其组分差异的影响。实验表明,木质素在超临界乙醇中的转化率及产物收率均高于甲醇。当反应温度340℃,反应时间60min,木质素在超临界乙醇中的转化率和生物油收率比在甲醇中分别提高了16.23%和11.54%,残渣收率降低了16.23%。通过GC-MS和FTIR对生物油和残渣分析,发现生物油组分中芳香族化合物相对含量较高,在甲醇和乙醇溶剂中分别达到66.13%和58.84%;随着反应时间的延长,甲醇溶剂中残渣的醚键官能团逐渐增强,而在乙醇溶剂中则先增强后减弱。分析认为在木质素降解过程中,超临界乙醇和甲醇均可产生氢自由基作为供氢体,攻击木质素及其大分子片段中的官能团,同时使液化产物中的活性片段减活,减弱重聚合反应,从而更利于芳烃产物的生成。而甲醇在液化过程中容易与木质素断键产生的苯酚中间体发生脱氢缩合反应,通过醚键聚合产生长链芳香族化合物,形成残渣,降低生物油收率。  相似文献   

17.
We studied the effects of the addition of large neutral amino acids, such as tyrosine (Tyr) and tryptophan (Trp), in mice DBA/2J and tetrahybrid mice DBCB receiving a high-fat, high-carbohydrate diet (HFCD) for 65 days. The locomotor activity, anxiety, muscle tone, mass of internal organs, liver morphology, adipokines, cytokines, and biochemical indices of animals were assessed. The Tyr supplementation potentiated increased anxiety in EPM and contributed to a muscle tone increase, a decrease in the AST/ALT ratio, and an increase in protein anabolism in both mice strains. Tyr contributed to a decrease in liver fatty degeneration and ALT reduction only in DBCB that were sensitive to the development of obesity. The addition of Trp caused an increase in muscle tone and potentiated an increase in anxiety with age in animals of both genotypes. Trp had toxic effects on the livers of mice, which was manifested in increased fatty degeneration in DBCB, edema, and the appearance of micronuclei in DBA/2J. The main identified effects of Tyr on mice are considered in the light of its modulating effect on the dopamine neurotransmitter metabolism, while for the Trp supplement, effects were presumably associated with the synthesis of its toxic metabolites by representatives of the intestinal microflora.  相似文献   

18.
This study aimed to describe glutathione peroxidase 4 (GPx4) in rat oocytes, preimplantation embryos, and female genital organs. After copulation, Sprague Dawley female rats were euthanized with anesthetic on the first (D1), third (D3), and fifth days of pregnancy (D5). Ovaries, oviducts, and uterine horns were removed, and oocytes and preimplantation embryos were obtained. Immunohistochemical, immunofluorescent, and Western blot methods were employed. Using immunofluorescence, we detected GPx4 in both the oocytes and preimplantation embryos. Whereas in the oocytes, GPx4 was homogeneously diffused, in the blastomeres, granules were formed, and in the blastocysts, even clusters were present mainly around the cell nuclei. Employing immunohistochemistry, we detected GPx4 inside the ovary in the corpus luteum, stroma, follicles, and blood vessels. In the oviduct, the enzyme was present in the epithelium, stroma, blood vessels, and smooth muscles. In the uterus, GPx4 was found in the endometrium, myometrium, blood vessels, and stroma. Moreover, we observed GPx4 positive granules in the uterine gland epithelium on D1 and D3 and cytoplasm of fibroblasts forming in the decidua on D5. Western blot showed the highest GPx4 levels in the uterus and the lowest levels in the ovary. Our results show that the GPx4 is necessary as early as in the preimplantation development of a new individual because we detected it in an unfertilized oocyte in a blastocyst and not only after implantation, as was previously thought.  相似文献   

19.
《云南化工》2019,(9):189-194
根据环境保护部会同工业和信息化部、卫生计生委制定了《优先控制化学品名录(第一批)》共22种优先控制化学品,结合云南省化学品生产使用情况,确定云南省17种优先控制化学品生产使用。选取生产使用量较大,涉及企业较多的甲醛、萘、二氯甲烷、三氯甲烷四种优先控制化学品作为代表,重点分析这四种危险化学品的性质和常见的生产使用工艺,总结云南地区的流域分布、区域分布、行业分布及用途情况,以便于云南省优先控制化学品污染的防治,以及污染物的在优先控制化学品方面的来源解析和在环境中的迁移转化规律研究提供相应的理论支撑,为环保部门、应急部门等相关政府部门对优先控制化学品的控制和管理提供新思路。  相似文献   

20.
The ideal immunosuppressive regimen should provide for excellent immunosuppression with no side effects. Yet, current immunosuppressive therapy regimens commonly used in clinical applications fail to meet this criterion. One of the complications caused by immunosuppressive drugs is mineralization disorders in hard tissues. In this study, we evaluated the effects of three immunosuppressive therapies used after transplantation on the levels of potassium, iron, chromium, zinc, aluminum, sodium and molybdenum in the bones and teeth of female rats and their offspring. The study was conducted on 32 female Wistar rats, subjected to immunosuppressive regimens (cyclosporine A, mycophenolate mofetil and prednisone; tacrolimus, mycophenolate mofetil and prednisone; and cyclosporine A, everolimus and prednisone). The hard tissues of rats were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES, ICAP 7400 Duo, Thermo Scientific) equipped with a concentric nebulizer and a cyclonic spray chamber. All the immunosuppressive regimens included in the study affected the concentrations of the studied minerals in hard tissues of female rats and their offspring. The therapy based on cyclosporine A, everolimus and prednisone led to a decline in the levels of iron in bone, zinc in teeth, and molybdenum in the bone and teeth of mothers, while in the offspring, it caused a decline of bone potassium, with a decrease in iron and increase of molybdenum in teeth. Moreover, the regimen caused an increase in aluminum and chromium in the teeth and aluminum in the bones of the offspring, and consequently, it seems to be the therapy with the most negative impact on the mineral metabolism in hard tissues.  相似文献   

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