Cyclohexane solubility

Coal tar pitch volatiles measurement of particulates and cyclohexane soluble material in air Lab method using filters and gravimetric analysis 68... 

Determination of rubber process dust and mbber fume (measured as cyclohexane-soluble material) in air... 

MDHS47 Rubber fumes in air, measured as total particles and cyclohexane soluble material . 

MDHS48 Newspaper print rooms measurement of total particulates and cyclohexane soluble... 

The reaction of EPR with dicumyl peroxide (DCP) at 180°C yielded a fraction insoluble in cyclohexane at 22 C. The presence of maleic anhydride (MAH) in the EPR-DCP reaction mixture increased the amount of cyclohexane-insoluble gel. However, the gel concentration decreased as the DCP concentration increased. The MAH content of the soluble polymer increased when either the MAH or the DCP concentration increased. The molecular weight of the soluble polymer increased with increasing MAH concentration and decreased with increasing DCP concentration in the reaction mixture. The products from the EPR-DCP and EPR-MAH-DCP reactions were soluble in refluxing xylene and were fractionated by precipitation with acetone. The presence of stearamide in the EPR-MAH-DCP reaction increased the amount and the molecular weight of the cyclohexane-soluble polymer. 

CYCLOHEXANE EXTRACTION. A 5-6g portion of the product was cut into small pieces and stirred in 250 ml cyclohexane at room temperature for 60 hr. The insoluble fraction was separated by filtering the solution through cheesecloth. The cyclohexane-soluble fraction was recovered by distilling the solvent in vacuo and the polymer was dried in vacuo at 40 C for 24 hr. 

The presence of 0.25-0.5 wt-% DCP at 180°C resulted in the formation of about 20% of a cyclohexane-insoluble fraction. The presence of 5 wt-% MAH (based on EPR) increased the amount of cyclohexane—insoluble gel, whose concentration decreased from 65% to 27% as the DCP content increased from 0.25 to 1.0 wt-% (based on EPR), respectively. The cyclohexane-soluble polymer contained about 1 wt-%... 

When the DCP concentration was kept constant at 1 wt-% while the MAH concentration in the charge increased from 5 to 20 wt-%, the amount of cyclohexane-insoluble polymer decreased from 29 to 23%. The [Vf] of the cyclohexane-soluble polymer increased and its MAH content decreased, as the MAH concentration in the charge increased (Table II). 

When stearamide (SA) was present in the DCP—MAH mixture added to EPR at 180 C, the amount of cyclohexane-insoluble EPR-g—MAH decreased, analogous to the effect of SA in reducing crossliriking in the PE-MAH-peroxide reaction (8,9). The of the cyclohexane-soluble EPR-g-MAH increased when SA was present in the reaction mixture, analogous to the effect of SA in reducing degradation in the PP-MAH-peroxide reaction (Table III). 

Rubber fumes in air, measured as total particles and cyclohexane soluble material . Newspaper print rooms measurement of total particulates and cyclohexane soluble material in air. 

Source Apportionment Models for the Cyclohexane-Soluble Fraction of Respirable Suspended Particulate Matter. Stepwise multiple regression analysis was used to determine the coefficients of the source tracers for the models proposed for CYC in equations (7)-(9). These models are shown in Table IV. As expected from the factor analyses, the coefficient for V, accounting for the greatest proportion of the variance of CYC, was fitted first into the equation. Equation (14) was the simplest and the F value was slightly higher than for equations (15) and (16). In addition, as will be discussed later in this paper, the coefficient for PB was in reasonable agreement with the ratio of CYC /PB for samples collected in the Allegheny Tunnel. 

SOURCE APPORTIONMENT MODELS FOR CYCLOHEXANE-SOLUBLE PARTICULATE ORGANIC MATTER ... 

Cyclohexane solubility insoluble Soluble Insoluble insoluble... 

HVL-P) was extracted with two solvents once with ethanol, and once with cyclohexane at room temperature and a solvent/sample ratio of 10. HVL-P, the ethanol-soluble fraction (ES) of HVL, and cyclohexane-soluble fraction (CyS) of HVL-P were distilled at temperatures ranging from 250° to 365°C under a variable vacuum down to 2 torr. Distillable fractions were designated "light , "middle" and "heavy" with the undistilled part termed "resid". The "light" fraction was yellowish and fluid up to -5°C the "middle" fraction was reddish and fluid at room temperature but solidified at lower temperatures, while the "heavy" fraction was red, and the "resid" fraction was black. 

The data in Table HIlikewise show a major difference between solvent extraction and distillation. Cyclohexane soluble material, CyS, had a wide spread in molecular weight as did HVL-P itself. Cyclohexane dissolved all of the Light and Middle fractions, and about 50% of the Heavy fraction and Resid in HVL-P. Thus, cyclohexane extraction is not as effective as distillation... 

Comparison of Distillation Products from HVL-P and its Cyclohexane Soluble Fraction... 

One of the most salient features of the detailed MS data summarized in Tables II-V is the similarity of the components determined in the light asphaltenes to those generally found in the cyclohexane-soluble fractions. Asphaltenes are simply more polar than the cyclohexane solubles, but less polar than the polar fraction separated from the cyclohexane-soluble fraction. This is attributable to the fact that asphaltenes contain significant amounts of neutral components. The overall amount of polar components is much higher in asphaltenes than in the cyclohexane solubles, and this is the factor that is... 

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