Dibutyl phthalate, atomization

Hogan (H12) obtained Rc values of 0.01-10 C/kg. With dibutyl phthalate, however, he reports a mode of atomization in which no liquid jets could be seen with a microscope and for which Rc values of 105 C/kg were measured, corresponding to singly ionized dimer molecules. No particles could be formed with silicone pump oil, whereas charges of 200-400 C/kg were obtained with suspensions of either Cab-0-Sil4a or carbon in glycerine. 

Shaffer (S5) also made some exploratory evaluations of the electrostatic atomization of dibutyl phthalate using a camel s hair brush for the atomizing nozzle. On a count basis 73% of the particles were smaller than 10 microns and the largest particle obtained was 40 microns. The energy input corresponded to 0.5 cal/g liquid atomized (0.00026 kWh/lb) and the charge level on the particles as atomized corresponded to a value of Sps of the order of 3-5 V/micron. Current and flow rate measurements reported by Vonnegut and Neubauer (V4) would correspond to an energy input of 0.1 kWh/lb. 

Aliphatic chains are particularly susceptible to attack by HO radicals and attack on these chains represents the major mode of contaminant degradation. This is certainly the case for degradation of dibutyl phthalate [18] with the most labile H atom being that on the methylene group in a-position to the ester function (Struct. 1). 

In 10, there are two remote stereogenic centers at phosphorus and it was isolated as an almost equimolecular mixture of the two sets of diastereoisomers, that is, (RR/SS) and (RS/SR). In each chiral diastereoisomer, the phosphorus atoms are nonequivalent and four distinct 31P resonances were obtained almost in a 1 1 1 1 ratio <1997J(P2)1445>. The kinetics of the thermal decomposition of 11 in dibutyl phthalate was studied. The high rate of decomposition was probably determined by mutual steric influence of the bulky dinitromethylene moieties <2006RJC499>. 

Plasticizers (see also Chapter 1) are essentially nonvolatile solvents for PVC. At the processing temperature of about 150°C, molecular mixing occurs in a short period of time to give products of greater flexibility. Phthalates prepared from alcohols with about eight carbon atoms are by far the most important class and constitute more than 70% of plasticizers used. For economic reasons, diisooctyl phthalate (DIOP), di-2-ethylhexyl phthalate (DEHP or DOP), and the phthalate ester of the C7-C9 0x0-alcohol, often known as dialphanyl phthalate (DAP) because of the ICI trade name Alphanol-79 for the C7-C9 alcohols, are used. DIOP has somewhat less odor, whereas DAP has the greatest heat stability. Dibutyl phthalate and diisobutyl phthalate are also efficient plasticizers and continue to be used in PVC (except in thin sheets) despite their high volatility and water extractabihty. 

About seven epoxy groups are reacted in this way for each nitrogen atom in the catalyst. Phenols are also included and act as accelerators in the curing reaction. Silicone resins may be added as flow agents and dibutyl phthalate has a plasticizing action. 

Atomization—Liquid aerosols of readily melted solids may be generated by direct atomization using, for example, a pneumatic nebulizer such as the Collision. When a pneumatic atomizer is used, the aerosol concentration may be varied by changing the pressure of the atomizer air supply. The mass median diameter of the aerosols produced by the small pneumatic nebulizer is typically in the micrometer range. The direct atomization method was applied to dimethyl-phthalate, a liquid, and dibutyl phosphate, a low-melting solid. 

A lot of plasticizers typically with two ester groups have been described in the literature [39] including aliphatic diesters of phthalic acid, like diethyl phthalate, and diesters of aliphatic dicarboxylic acids like dibutyl adipate or azelate [22] as well as glycerol triacetate (triacetin), citrate esters, and phosphates [39]. Although these kind of plasticizers work well for decades in various applications, the accelerated retention test shows [39] that exudation and volatilization must be taken into account and can cause changes in the material performance. Thus, attempts have been made to synthesize long-chain esters of cellulose (LCCEs) with acid chain lengths of up to 20 carbon atoms (see [21] and references cited therein), which could be processed without external plasticizers. Positive results are reported for cellulose acetate hexanoate and cellulose acetate nonanoate [21] but these esters did not go into production. 

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