Extrusion heat preparation

Clay was supplied by a clay quarry located in Bailen, Jaen (Spain) and was obtained by mixing three types of raw clay in equal parts red, yellow and black clay. Clay was crushed and ground to yield a powder with a particle size suitable to pass through a 150 pm sieve. The waste, olive wastewater and olive oil wastewater were supplied by a local olive oil extraction plant and used directly without any prior pretreatment. The ceramic paste for the extrusion was prepared by adding fresh water (FW) or residue resulting from olive oil extraction (OW or OOW) to the clay in a mixer. The amoimt of added water in the mixer depends on clay plasticity and on its consistency while performing the extrusion. In the present work 22 wt % of FW, OW or OOW was added to the clay. The same value as used at industrial scale for this kind of clay mixture. Extrusion was carried out in a laboratory Venco extruder. Extruded test pieces were dried at room temperature for about 24 h, and then heated in an oven at 110 °C until constant weight for at least 24 h. 

The flow rate is influenced by all the vari-bles that can exist in preparing the melt dur-ig extrusion such as die heat and pressure /ith time in the die. Unfortunately, in spite of... 

A cycloaddition process involving dipole 22, readily prepared from thiazolidine 21, was reported to produce adducts such as 23 in the presence of sufficiently reactive dipolarophiles <2000T10011>. These adducts furnished substituted pyrazolo[l,5- ]pyridines 24 in fair yields upon further heating and extrusion of sulfur. However, diphe-nylacetylene did not react with dipole 22 (Scheme 10). 

Elimination of CO2 from 21 requires higher temperatures. Reported protocols include the thermolysis without solvent at 130 °C (44), heating in solution at 150-230 °C (45), as well as in the gas phase at 600 °C (FVP) (46). For synthetic purposes, this method has been used for the preparation of sterically hindered olefins and represents an extension of the twofold extrusion methodology [cf. (47,48)]. 

Thermal bond transposition has been utilized successfully in the synthesis of a number of relatively heat-insensitive families of heteroannulenes, such as the triheteronin frame (20) constructed thermally from the tetracyclic valence tautomer and the tetrabenzo heteronins (18) obtained by thermal bond transposition of their spirostructured valence tautomers (113). Similarly, thermally induced bridge extrusion (C02) has been utilized as a means of preparing dihydrobenzazonine (112) (the direct photoprogenitor of aza[13]annulene 36a) from cycloadducts (104) (73TL3805). 

A number of factors for DOTAP-cholesterol/DNA complex preparation including the DNA/liposome ratio, mild sonication, heating, and extrusion were found to be crucial for improved systemic delivery maximal gene expression was obtained when a homogeneous population of DNA/liposome complexes (200-450 nm) was used. Cryoelectron microscopy showed that the DNA was condensed on the interior of liposomes between two lipid bilayers in these formulations, a factor that was thought to be responsible for the high transfection efficiency in vivo and for the broad tissue distribution (150). 

Thus far no reports have appeared on the isolation of 1,3-ditellurolylium cation salts in a pure state. Attempts to prepare 1,3-ditellurolylium boron tetrafluoride and its derivatives via treatment of 1,3-ditelluroles with tri-phenylmethyl boron tetrafluoride in MeCN solution failed (82TL1531). However, formation of the 1,3-ditellurolylium cation 74 was revealed by the H NMR spectrum in which the 2-H proton was shown to give a very low-field triplet (8 15.0 ppm, 4/Hh = 1.2 Hz). Cation 74 is sufficiently stable in solution only at low temperature. When an acetonitrile solution of 74 obtained from 1,3-ditellurole was heated to 30°C, the initial H NMR spectrum drastically changed to the A2X spectral pattern (8 13.8 ppm, d and 10.3 ppm, /, iJ = 6.9 Hz) corresponding to the spectrum expected for the 1,2-ditellurolylium cation 75. A plausible reaction scheme is shown below. A further elevation of the temperature of the solution resulted in an unidentified destruction process accompanied by the extrusion of elemental tellurium. 

Starch can readily be modified by concurrent heat, application of moisture, and pressure. Such modifications may be conducted in extruders. Low moisture content favors formation of water-soluble starch with increased water-binding capacity, 65a 65e The solubility, water binding-capacity, and viscosity of gels prepared from extruded starch do not show linear relationships against either the moisture content in starch or the extrusion temperature.65c-65f Such extruder variables as the type of screw (either single or twin), pattern of the barrel and die heating, screw velocity, and geometry of the screw thread are also essential factors.65 ... 

Phenanthridine is known to undergo direct amination readily with hydride extrusion (the Chichibabin reaction) and further examples have been reported.22 More interesting is the preparation of 6-aminophenanthridine in high yield by the action of the sodium salt of N,N-dimethylhydrazine on phenanthridine in benzene. The adduct (224) (R = Me) loses dimethylamine on heating leaving the sodium salt of the 6-amino compound (225).318... 

Pyrones behave as dienes and react with bismaleimides giving biscycload-ducts [62-65]. By heating, carbon dioxide extrusion takes place with formation of bisdienes. This reaction was used to prepare a polyimide with a bicyclooctene structure [51] (Fig. 15). 

Flory-Huggins approach, may be somewhat low even with highly crystalline preparations of A- or B-type starch lintners (DP —15). Despite its theoretical limitations, the Flory analysis (as illustrated in Figure 8.10 inset) can be used to simulate the melting behavior of starch in practical applications (e.g. extrusion cooking, baking) and to compare the thermal stability of different starch materials under dynamic heating at various moisture conditions.20,25 240 337... 

Just in the USA during 2001, the man-made plastic fiber industry had over 90 plants with sales of 13 billion and employed about 45,000 people. Fabrication processes are diverse both in technology and equipment design. They have common steps that include preparation of reactants, polymerization, plastic recovery, plastic extrusion, and supporting operations. In some preparation operations, solvents are used to dissolve or dilute monomer and reactants. Solvents are also used to facilitate the transportation of the reaction mixture throughout the plant, to improve heat dissipation during the reaction, and to promote uniform mixing. Solvent selection is optimized to increase monomer... 

Intermittent accumulator EBM machines use a normal conventional axially fixed continuously operating extruder to prepare the melt. The accumulator is a heated reservoir where the melt is temporarily stored in the intervals between parison extrusion (similar action of a two-stage injection molding machine (IMM) as reviewed in Chapter 4. Also used is a conventional reciprocating IMM that delivers melt through a die into a blow mold. 

Dithiete 753, when heated, undergoes cycloaddition through its tautomeric dithione 754 to produce 1,4-dithiin 755 which gives the thiophene 756 by extrusion of sulfur. Heating 753 with alkynes affords the thiophenes 757 (Scheme 118) <1999JOC8489>. 2,3,4,5-Tetra(2-chlorotetrafluoroethyl)thiophene 758 can be prepared in a similar way. Irradiation of 758 produces the Dewar thiophene 759 <2000JFC(102)323>. 

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