Clay, attapulgus

Gas Phase. The gas-phase methanol hydrochlorination process is used more in Europe and Japan than in the United States, though there is a considerable body of Hterature available. The process is typicaHy carried out as foHows vaporized methanol and hydrogen chloride, mixed in equimolar proportions, are preheated to 180—200°C. Reaction occurs on passage through a converter packed with 1.68—2.38 mm (8—12 mesh) alumina gel at ca 350°C. The product gas is cooled, water-scmbbed, and Hquefied. Conversions of over 95% of the methanol are commonly obtained. Garnma-alurnina has been used as a catalyst at 295—340°C to obtain 97.8% yields of methyl chloride (25). Other catalysts may be used, eg, cuprous or zinc chloride on active alumina, carbon, sHica, or pumice (26—30) sHica—aluminas (31,32) zeoHtes (33) attapulgus clay (34) or carbon (35,36). Space velocities of up to 300 h , with volumes of gas at STP per hour per volume catalyst space, are employed. 

After the addition of acid chloride, about 25 ml of methylene chloride was used to rinse the residual acid chloride into the flask. The mixture was stirred for about 3 h. The pH was then adjusted to between 9.5 and 10 and the solution was stirred for an additional hour. The organic layer was separated from the aqueous layer and washed once with 5% NaOH solution. The solution was dried over calcium sulfate and the methylene chloride was evaporated leaving about 10.36 g (69%) of crude product. Decolorizing three times with Attapulgus clay yielded a light yellow brown methylene chloride solution which, on removal of solvent, gave about 5.2 g of product (35%). 

Fuller s earth a clay that has high adsorptive capacity for removing color from oils attapulgus clay is a widely used fuller s earth. 

The neutral Lewis bases were removed from the acid- and base-free bitumen by chromatography in cyclohexane on ferric chloride/Attapulgus clay, packed in a column above Amberlyst A-29. The ratio of sample to ferric chloride/Attapulgus clay to anion resin was 1 13 17. Neutral Lewis bases were recovered by successive column elution with 1,2-di-chloroethane and 40% methanol-60% benzene to provide two subfractions. The methanol was removed from subfraction II, after which the ferric chloride was removed from the fraction by dissolving the sample in 1,2-dichloroethane and contacting the sample with the A-29 resin. 

Neutral Lewis bases were removed by contacting the acid- and base-free bitumen with ferric chloride/Attapulgus clay in a column system. Weakly adsorbed complexes were desorbed with 1,2-dichloroethane while strongly held complexes were desorbed with benzene and methanol. This procedure provided two neutral Lewis bases fractions for analysis. 

ELUTION THROUGH ATTAPULGUS CLAY BUT RETAINED ON SILICA... 

The separation of resin acids and bases has been described previously (II, 12), see also comments in (14). The percentage of resins, as determined for deasphaltened Athabasca bitumen by their separation on an Attapulgus clay column, was 34%, while combined acids, bases, and Lewis bases amounted to 25.9% of the whole bitumen. Thus, 8.1% of material retained as resins on Attapulgus clay did not interact with the ion exchangers or the complexation column and appeared in the polyaromatic fraction. The distribution of material within the resin fraction was 46.1% acids, 21.9% bases, and 32% neutral compounds. Thus, the pattern of acid and base distribution is similar for the resins and asphaltenes, except for a higher proportion of neutral material present in the resins. 

A study of MW distribution for precipitated asphaltenes and the derivation of conclusions about bitumen or asphalt properties from it has severe limitations since this complex mixture exhibits a considerable overlap of GPC curves for all the fractions obtained in a conventional separation procedure. Similarly, the resins separated on clay and the eluted hydrocarbons exhibit overlap, as shown by Figures 5 and 6. Figure 5 demonstrates the GPC profiles of Athabasca asphaltenes (nC5) and resins (Attapulgus clay—total resin eluent)... 

This method was preferred to a previous one using Attapulgus clay in batch (28) because it was faster. 

B. W. Lew, M. L. Wolfrom and R. M. Goepp, Jr., J. Am. Chem. Soc., 68, 1449 (1946). A suitable fuller s earth clay was Florex XXX it was produced by the Flori-din Co., Warren, Pa. Other selective clays were Floridin XXX (Floridin Co., Warren, Pa.), Types A and AA Attapulgus Clays (Attapulgus Clay Co., Attapulgus, Ga.), Bleaching Clay 260 (Industrial Minerals and Chemical Co., Berkeley, Calif.), and J. Neutrol (Filtrol Corp., Los Angeles, Calif.). 

Ferric Chloride on Attapulgus Clay. Ferric chloride hexahydrate (40 g), a 10% solution in methanol, was contacted with Attapulgus clay (252 g) for 8 hr. The ferric chloride-Attapulgus clay was filtered, washed several times with cyclohexane, extracted with cyclohexane for 24 hr in a Soxhlet extractor to remove nonadsorbed metallic salt, and dried at room temperature. The material contained 0.7-2.0 wt % of iron. 

Separation Procedure. The petroleum asphaltenes were separated into five fractions acids, bases, neutral nitrogen compounds, saturate hydrocarbons, and aromatic hydrocarbons. Acids were isolated using anion-exchange resin, bases with cation-exchange resin, and neutral nitrogen compounds by complexation with ferric chloride adsorbed on Attapulgus clay. The remaining hydrocarbon fraction is separated on silica gel to produce saturate and aromatic hydrocarbon fractions. 

Further separation of maltenes into resins (polar aromatics) and oils was achieved in selected cases by adsorption onto Attapulgus clay using a modification of ASTM D2007 (clay-gel separation). 

Many early literature reports describe the use of clays for this transformation. An interesting example is a 1957 paper by Wystrach et al. [3] who described the isomerization of 1 over 1 % calcined Attapulgus clay to yield 2 and 3 as the major products, and also postulated a mechanism for this transformation [4]. It is also worth noting that they were the first group to realize the importance of the stereochemistry of adsorption in studies relating to isomerization over clays. 

Petroleum (16). Where applicable, samples are distilled and the 200°C+ fraction retained, spiked with 14C BaA and BaP, and analyzed for PNA content. Samples are first separated on Attapulgus clay to remove the very polar heteroatom portion of the sample. The Attapulgus clay was purchased from the National Bureau of Standards to have adsorptive characteristics as specified in ASTM D 2007. The column, 760 mm X 22 mm, is fitted with a 500-mL reservoir and a Teflon stopcock 170 g of clay is placed in the column and prewet with 50 mL of n-pentane. A 15- to 20-g sample, dissolved in 100 mL of pentane, is placed on the column. The sample is then successively eluted with 600 mL of n-pentane and 500 mL of acetone. The entire separation is carried out in a blanket of nitrogen. Each fraction is carefully evaporated on a steam bath under nitrogen until a constant weight is obtained. 

Attagel 40 or 50 2-5 Attapulgus clay Disperse with high shear. 

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