Neutral-nitrogen fractions from

Compounds Present in the Acid and Neutral-Nitrogen Fractions from Feedstock and Hydrotreated Anthracene Oil... 

Zapelena, M. J., Zalacain, I., Pena, P. D., Astiasaran, I., and Bello, J. 1997. Effect of the addition of a neutral proteinase from Bacillus subtilis (Neutrase) on nitrogen fractions and texture of Spanish fermented sausage. J. Agric. Food Chem., 45, 2798-2801. 

It was also of interest to establish the fate of acids, bases, and neutral nitrogen compounds on silica and alumina. For this purpose, the acids, bases, and neutral nitrogen compounds isolated on ion exchangers and Fe /clay, respectively, were applied on a silica column. Elution of hydrocarbons with n-pentane yielded 0.29% material, which was separated on alumina into mono + diaromatics (0.1%) and polyaromatics (0.24% ) (Figure 4). Thus, if ion exchangers and the Fe /clay column are omitted, there remains only about 0.8% impurities stemming from acid and base fractions present in the total mono- and diaromatic fractions. 

Another way to separate nitrogen compounds from hydrotreated shale oil products is by adsorption chromatography. Experiments have been conducted where basic and neutral alumina have been used to separate shale oil into specific nitrogen-type fractions. Both a pumped-flow and gravity-flow method were executed. However, it was determined that the pumped-flow procedure was better since it enabled more control over experimental parameters such as flow rate. This separation scheme could be very useful because it has been applied to shale oil products produced under different hydrotreating conditions... 

The acetone wash (aromatic fraction) from the gel separation is then separated on 2% deactivated Woelm Neutral Alumina (Nutritional Biochemicals, Cleveland, Ohio). The column is 890 mm X 6.5 mm and is fitted with a 50-mL reservoir and tapered end. Fifteen grams of the alumina are placed in the column. The column is prewet with 25 mL of cyclohexane and pressurized to 15 lb of nitrogen. One-fifth gram of the acetone fraction from the silica gel separation is dissolved in 10 mL of cyclohexane and placed on the column. When the cyclohexane has entered the column, the following washes are added 15 mL cyclohexane 30 mL 10% benzene in cyclohexane 30 mL 20% benzene in cyclohexane 30 mL benzene and 30 mL 55% benzene in methanol. 

As the United States begins to rely more on coal combustion and synfuel derived from fossil fuels, the composition of emissions from these sources may change with coal and shale that have high nitrogen contents, the amount of azaarenes is likely to increase. Ho et al. (27) have provided some preliminary analysis of shale oil and coal-derived oil on a weight percent basis. The neutral azaarene fraction accounted for 1.4% of the shale oil and 9.5% of the coal-... 

In addition, liver preparations from rats induced with Aroclor 1254 (Monsanto) showed the best general applicability for activation. However, individual differences in effectiveness do occure.g., in the results given in Table 5, variously induced preparations show obvious differences between fraction 9 (the basic fraction. Be) and fraction 14 (the neutral/methanol fraction). The Aroclor-induced preparation works best with the neutral fraction (PAHs ), whereas the phenobarbital-induced preparations work more efficiently with the basic fraction (heterocyclic nitrogen compounds, aromatic amines, aza-arenes ). 

Because phenols are weak acids, they can be freed from neutral impurities by dissolution in aqueous N sodium hydroxide and extraction with a solvent such as diethyl ether, or by steam distillation to remove the non-acidic material. The phenol is recovered by acidification of the aqueous phase with 2N sulfuric acid, and either extracted with ether or steam distilled. In the second case the phenol is extracted from the steam distillate after saturating it with sodium chloride (salting out). A solvent is necessary when large quantities of liquid phenols are purified. The phenol is fractionated by distillation under reduced pressure, preferably in an atmosphere of nitrogen to minimise oxidation. Solid phenols can be crystallised from toluene, petroleum ether or a mixture of these solvents, and can be sublimed under vacuum. Purification can also be effected by fractional crystallisation or zone refining. For further purification of phenols via their acetyl or benzoyl derivatives (vide supra). 

Triethylamine was fractionally distilled from lithium aluminum hydride under nitrogen and acryloyl chloride was distilled under nitrogen. 1,1,2-Trichlorotrifluoroethane (Freon 113) was distilled from phosphorus pentoxide under nitrogen. Azobisisobutyronitrile (AIBN) was used as received. Methyl ethyl ketone peroxide (MEKP) (9% Organic Peroxide VN 2550) was obtained from Witco. Alumina (neutral, Brockman activity 1, 80-200 mesh) was obtained from Fisher Scientific Co. All reagents were obtained from Aldrich unless otherwise specified. 

The chemical structures of the amino acids found in soil-solids are shown in Fig. 6 [25] while the quantities of amino acids found in HS extracted from various solid phases are represented in Fig. 7 (data were collected from Ghosh and Schnitzer [37] and Schnitzer et al. [38]). High levels of amino acid nitrogen were found in HA, FA, and humin fractions, indicating incorporation of common acidic and some neutral amino acids, particularly glycine, alanine, and valine. 

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