Lump-breaking

A study was made of nucleation in PE foams produced in a counter-rotating extruder using talc powders and masterbatches as nucleating agents and CFG and HCFC blowing agents. The results indicated the importance of shear force in nucleation, as proposed in the lump cavity nucleation model and demonstrated by melt temperature effects observed in these experiments. It was shown that shear enhancement via lump break-up was not a vital mechanism in nucleation. 6 refs. 

Carry out this preparation precisely as described for the a-compound, but instead of zinc chloride add 2 5 g. of anhydrous powdered sodium acetate (preparation, p. 116) to the acetic anhydride. When this mixture has been heated on the water-bath for 5 minutes, and the greater part of the acetate has dissolved, add the 5 g. of powdered glucose. After heating for I hour, pour into cold water as before. The viscous oil crystallises more readily than that obtained in the preparation of the a-compound. Filter the solid material at the pump, breaking up any lumps as before, wash thoroughly with water and drain. (Yield of crude product, io o-io 5 g.). Recrystallise from rectified spirit until the pure -pentacetylglucose is obtained as colourless crystals, m.p- 130-131° again two recrystallisations are usually sufficient for this purpose. 

Place 50 g. of o-chloronitrobenzene and 75 g. of clean dry sand in a 250 ml. flask equipped with a mechanical stirrer. Heat the mixture in an oil or fusible metal bath to 215-225° and add, during 40 minutes, 50 g. of copper bronze or, better, of activated copper bronze (Section 11,50, 4) (1), Maintain the temperature at 215-225° for a further 90 minutes and stir continuously. Pour the hot mixture into a Pyrex beaker containing 125 g. of sand and stir until small lumps are formed if the reaction mixture is allowed to cool in the flask, it will set to a hard mass, which can only be removed by breaking the flask. Break up the small lumps by powdering in a mortar, and boil them for 10 minutes with two 400 ml. 

Beckmann rearrangement of benzophenone oxime to benz-anilide. Dissolve 2 g. of benzophenone oxime in 20 ml. of anhydrous ether in a small conical flask and add 3 g. of powdered phosphorus pentachloride (or 3 ml. of pure tbionyl chloride). Distil off the solvent and other volatile products on a water bath CAUTION ether), add 25 ml. of water, boil for several minutes and break up any lumps which may be formed. Decant the supernatant liquid, and recrystallise, in the same vessel, from boiling alcohol. The product is benzanilide, m.p. 163° confirm this by a mixed m.p. determination with an authentic specimen. 

Dissolve 5 g. of phenol in 75 ml. of 10 per cent, sodium hydroxide solution contained in a wide-mouthed reagent bottle or conical flask of about 200 ml. capacity. Add 11 g. (9 ml.) of redistilled benzoyl chloride, cork the vessel securely, and shake the mixture vigorously for 15-20 minutes. At the end of this period the reaction is usually practically complete and a sohd product is obtained. Filter oflf the soUd ester with suction, break up any lumps on the filter, wash thoroughly with water and drain well. RecrystaUise the crude ester from rectified (or methylated) spirit use a quantity of hot solvent approximately twice the minimum volume required for complete solution in order to ensure that the ester does not separate until the temperature of the solution has fallen below the melting point of phenyl benzoate. Filter the hot solution, if necessary, through a hot water funnel or through a Buchner funnel preheated by the filtration of some boiling solvent. Colourless crystals of phenyl benzoate, m.p. 69°, are thus obtained. The yield is 8 g. 

Tetrahydrofurfuryl chloride. Place 204 g. (194 ml.) of freshly distilled tetrahydrofurfuryl alcohol (b.p. 177°) and 174 g. (178 ml.) of dry pyridine in a 1-litre three-necked flask, fitted with a dropping funnel, mechanical stirrer and thermometer. Cool in an ice bath, stir vigorously and add 250 g. (153 ml.) of freshly distilled thionyl chloride at the rate of 3-5 drops per second. A pasty crystalline mass begins to separate and the temperar ture commences to rise rapidly when one-third to one-half of the thionyl chloride has been added subsequently the mass largely redissolves and a dark brown liquid forms. Remove the ice bath when the addition is complete and stir the mixture for 3-4 hours. Pour the reaction product into a large separatory funnel and extract with seven 250 ml. portions of ether break up any lumps that may form with a glass rod. Remove the ether from the combined extracts by distillation, wash the residue with three 50 ml. portions of water, dry with anhydrous magnesium sulphate and distil under reduced pressure. The yield of tetrahydrofurfuryl chloride, b.p. 47-48°/15 mm., is 180 g. 

Low Temperature Carbonization. The Lurgi Sptlgas process was developed to carbonize brown coal at relatively low temperatures to produce tars and oils (Fig. 5). A shaft furnace internally heated by process-derived fuel gas (Spblgas) is used. The product can range from a friable coke breeze to hard lump coal depending on the quality of the briquettes used in the feed. The briquettes, made in normal extmsion presses, break down into smaller sizes during carbonization. 

In rniiller mixers the rotation of the circular pan or of the plows brings the material progressi elv into the path of the rniillers, where the intensh e action takes place. Figure 18-46 shows one tvpe of mixer, in which the rniillers and plows re ol e around a stationaiw turret in a stationaiw pan. The outside plow rno es material from the crib wall to the path of the following rniiller the inside plow rno es it from the central turret to the path of the other rniiller. The rniillers crush the material, breaking down lumps and aggregates. 

In the wet process, the clay is masticated in a pug mill to break up lumps and then dispersed with a dispersing aid and water to make a 40 percent solids slip of low viscosity. A hi -speed agitator such as a Cowles dissolver is used for this purpose. Sands are settled out, and then the clay is classified into two size fractious in either a Hydrosettler or a continuous Sharpies or Bird centrifuge. The fine fraction, with sizes of less than 1 [Lm, is used as a pigment and for paper coating, while the coarser fraction is used as a paper filler. 

It is advisable to stir the mixture during the cooling in order to break up the lumps and thus obtain a product that can be more easily filtered. 

Near the end of the addition of the acetic acid solution it is usually desirable to raise the stirrer temporarily to break up the lumps which form at the surface of the solution. 

The purity of the product depends largely on the efficient breaking up of all lumps and the subsequent washing. 

Cake disposal is relatively straightforward. Cakes may be discharged into bins that are trucked away or transported with a belt conveyor. With very large filter presses a well formed cake may weigh 200-300 kg per chamber and when it falls into a bin or onto a belt conveyor in one solid piece the impact is very high. Hence, special measures are required to break and de-lump the sole hard cake and, for belt conveyors, it is also recommended to increase the number of belt support rollers below the discharge chute at the point of impact. 

The reaction mixture is diluted with 250 ml of water, the mixture is transferred to a 2 liter flask using methanol as a wash liquid, and the organic solvents are distilled at 20-25 mm using a rotary vacuum evaporator. The product separates as a solid and distillation is continued until most of the residual toluene has been removed. The solid is collected on a 90 cm, medium porosity, fritted glass Buchner funnel and washed well with cold water. After the material has been sucked dry, it is covered with a little cold methanol, the mixture is stirred to break up lumps, and the slurry is kept for 5 min. The vacuum is reapplied, the solid is rinsed with a little methanol followed by ether, and the material is air-dried to give 9.1 g (85%), mp 207-213° after sintering at ca. 198°. Reported mp 212-213°. The crude material contains 1.0-1.5% of unreduced starting material as shown by the UV spectrum. Further purification may be effected by crystallization from methanol. 

A solution of sodium ethylate is prepared from 60 g. (2.6 gram atoms) of clean sodium and 700 cc. of absolute alcohol (Note 1) in a 2-1. round-bottomed flask, equipped with a reflux condenser. To the hot solution is added a mixture of 234 g. (2 moles) of pure benzyl cyanide (Note 2) and 264 g. (3 moles) of dry ethyl acetate (Note 3). The mixture is thoroughly shaken, the condenser closed with a calcium chloride tube, and the solution heated on the steam bath for two hours before standing overnight (Note 4). The next morning the mixture is stirred with a wooden rod to break lumps, cooled in a freezing mixture to — io°, and kept at this temperature for two hours. The sodium salt is collected on a 6-in. Buchner funnel and washed four times on the funnel with 250-cc. portions of ether. The filter cake is practically colorless and corresponds to 250-275 g. of dry sodium salt, or 69-76 per cent of the calculated amount. The combined filtrates are placed in the freezing mixture until they can be worked up as indicated below. 

Gels made from citrus pectin have a small linear visco-elastic range. To puncture the gels takes a big but only short time effort. The gel breaks into small lumps immediately. In the... 

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