Methyl heptadecanoate

The new lipid occurred only in the plasma hpids of newborns and was not present in membrane hpids of red cell membranes or platelets. Total lipids were extracted from plasma and from red blood cell membranes and platelets. A total lipid profile was obtained by a three-directional PLC using silica gel plates and was developed consecutively in the following solvent mixtures (1) chloroform-methanol-concen-trated ammonium hydroxide (65 25 5, v/v), (2) chloroform-acetone-methanol-ace-tic acid-water (50 20 10 15 5, v/v), and (3) hexane-diethyl ether-acetic acid (80 20 1, v/v). Each spot was scraped off the plate a known amount of methyl heptadecanoate was added, followed by methylation and analysis by GC/MS. The accmate characterization of the new lipid was realized using NMR technique. 

C18H3602 methyl heptadecanoate 1731-92-6 35.00 0.8751 2 31321 C19H15N05 N-(9H-fluoren-2-ylmethoxycarbonyloxy)succini 82911-69-1 25.00 1.3130 2... 

Waste oil was collected from the restaurant in South China University of Technology. The saponification value was 200.3 mg KOH/g, from which, the average molecular weight of the waste oil was known to be 840.2. Novozym 435 (lipase B from Candida antarctica, 164 U/g, limit corresponds to the amount of enzyme that produces 1 pmol methyl oleate from triolein per minute at 35 °C) was kindly donated by Novozymes Co. (Denmark). Methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, methyl linolenate and methyl heptadecanoate (as an internal standard) were purchased from Sigma (USA). All other chemicals were also obtained commercially and of analytical grade. Ultrasonic irradiation experiments were carried out using an ultrasonic bath (Type NP-B-400-15 Newpower Co. Ltd., China). 

The reaction was carried out in 50-ml flask capped with a septum, incubated at 40 °C and in the presence or absence of ultrasonic irradiation. The reaction mixture contained 66 U Novozym 435, 10 g waste oil and 0.38 g methanol (1 molar equivalent). Samples of 100 pi were periodically withdrawn and centrifuged (12000 rpm, 10 min) and the upper layer was mixed with methyl heptadecanoate for GC analysis. In the ultrasonic pretreatment experiment, Novozym 435 was immerged into 10 g waste oil and exposed to ultrasonic irradiation for a predetermined period of time. 

Methyl myristate Isopropyl myristate Butyl myristate Methyl pentadecanoate Methyl palmitate Ethyl palmitate Isopropyl palmitate Methyl heptadecanoate Methyl stearate Ethyl stearate... 

The reagents employed were commercial soybean oil (Sadia, Brazil), analytical grade ethanol, butanol, oleic acid (extra pure), and hexane (Merck, Darmstadt, Germany). Methyl heptadecanoate (a chromatographic standard) was acquired from Sigma (St. Louis, USA). Sodium hydroxide and acetone were purchased from Vetec (Brazil). 

The samples were injected into a Varian gas chromatograph (CP-3380 model), equipped with a flame ionization detector (FID) and a CP WAX 52 CB capillary column 30 mxO.25 mm X 0.25 xm, and a split injection system with a 1 20 ratio. Injector and detector temperatures were kept at 250°C. The oven was initially maintained at 200°C for 4.5 min, then heated up to 210°C, and kept constant at this temperature for 0.5 min. After that, it was heated to 220°C for 0.5 min. The oven was heated again to 250°C and maintained at this temperature for 1.5 min. Hydrogen was used as the carrier gas at a 1.8 ml/min flow rate column pressure was set at 12 psi. A computer loaded with the Star Workstation 6.2 software was connected to the GC by a Star 800 Module Interface to automatically integrate the peaks obtained. Methyl heptadecanoate was the internal standard used. 

CAS 41669-30-1 EINECS/ELINCS 255-485-3 Synonyms Isooctadecanoic acid, isooctadecyl ester Isooctadecyl isooctadecanoate 16-Methylheptadecanoic acid, 16-methyl heptadecyl ester 16-Methyl heptadecyl 16-methyl heptadecanoate Definition Ester of isostearyl alcohol and isostearic acid... 

Methylheptadecyl 16-methyl heptadecanoate. See Isostearyl isostearate Methyl heptadienone 2-Methyl hepta-2,4-dien-6-one. See 6-Methyl-3,5-heptadien-2-one 6-Methyl-3,5-heptadien-2-one CAS 1604-28-0 EINECS/ELINCS 216-507-7 Synonyms Methyl heptadienone 2-Methyl hepta-2,4-dien-6-one 6-Methylhepta-3,5-dien-2-one... 

If the small molecule has a lower refractive index than the carrier solvent and the probe a higher refractive index than the carrier solvent, the calculated level of amount of probe adsorbed will be greater than it really is. If however, both the probe and the small molecule have lower refractive index than the carrier solvent, the amount of probe adsorbed will be smaller than it really is. The extent to which this problem occurs also depends upon the solubility of the small molecule in the carrier solvent. This effect has cansed problems in a recent study [13] of adsorption of various carboxylic acids on to metal hydroxides. Figure 3.4 shows both the heat of adsorption and amount of carboxylic acid adsorbed. It is evident that adsorption of stearic acid (octadecanoic acid) and isostearic acid (16-methyl heptadecanoic acid) from toluene affords apparently reduced levels of adsorption, relative to when adsorbed from heptane. This is due to both the probe and the water having lower refractive indices than toluene. DRIFTS analysis of the respective filler samples retrieved from the FMC cell, however, indicates similar levels of adsorption. Only in the case of adsorption from heptane is the level of adsorption in concordance with theoretical values. This is due to reduced solubility of water in heptane, relative to toluene. 

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