P-Xylylene dichloride

Methoxy-5-(2-ethylhexyloxy)-p-xylylene dichloride and triethyl phosphate were initially reacted to generate the corresponding phosphonate. Thereafter a mixture of the phosphonate (0.016 g), the Sep 1 product (0.5 g), and 50 ml of THF was charged into a reactor and treated dropwise at ambient temperature with potassium t-butoxide (0.07 g) dissolved in 5 ml of THF over a 10 minute period. The mixture reacted for 2.5 hours at ambient temperature and was then neutralized with acetic acid. The polymer was precipitated by pouring into methanol and dried, and the product was isolated. 

Figure 7.1 Equilibrium swelling in toluene vs concentration of initial polystyrene solution for the networks crosslinked with (1, 2) p-xylylene dichloride and (3) monochlorodimethyl ether to crosslinking degrees (1) 11, (2) 100, and (3) 43%.

Figure 7.5 Dependence of volume swelling in (1) n-hexane (2) methanol and (3) water on the crosslinking degree of networks prepared by crosslinking linear polystyrene with (a) p-xylylene dichloride and (b) methylal.

Table 7.2 Swelling (mlVg) of polymers based on linear polystyrene crosslinked with p-xylylene dichloride (measured by the weight of the dry and swollen product) Solvent Degree of crosslinking, (%)...

Table 7.7 Apparent density (papp g/cm ) and total pore volume (Mfo/CmVg) of hypercrosslinked networks based on linear polystyrene with a molecular weight of 3 X 10 Da and crosslinked with p,p-bis-chloromethyl-diphenyl, p-xylylene dichloride, or monochlorodimethyl ether...

XDC =p-xylylene dichloride DMM = dimethoxymethane CMM = tris(chloromethyl)mesitylene ... 

Hypercrosslinked networks were prepared by crosslinking linear polystyrene (I) with p-xylylene dichloride and styrene—0.7% DVB copolymer (II) with monochlorodimethyl ether X= 100%. 

Figure 7.28 Differential pore volume distribution over the diameters of polystyrene-standard coils, D, for the network prepared by crosslinking linear polystyrene with p-xylylene dichloride to 43% crosslinking degree (a) volume distribution and...

Figure 7.30 Electron macrographs of the networks prepared by post-crosslinking linear polystyrene (/M = 300,000 Da) with (a, b) p-xylylene dichloride (a) X=100%, (b) X=43% and (c, d) monochlorodimethyl ether (c) X=100%, (d) X=5% (a, b) two-step replicas, transmission electron microscopy, 46,600x (c, d) scanning electron microscopy, (c) 40,000x, (d) 100,000x. (After [198]).

Table 93 Properties of three-dimensional products prepared by self-condensation of p-xylylene dichloride (80°C, 20 h, 1,2-ethylene dichloride, SnCy...

Up to now four main groups of hypercrosslinked sorbents have been developed and intensively tested. The first group, Styrosorb 1, incorporates laboratory samples of nanoporous (microporous) single-phase sorbents prepared by intensive post-crosslinking Hnear polystyrene of about 300,000 Da molecular weight, dissolved in ethylene dichloride, with monochlorodi-methyl ether or p-xylylene dichloride. The irregular particles of these sorbents have pores with a diameter of about 20—30 A and display an apparent specific surface area as high as 1000—1500 m g. The pore volume of Styrosorb 1 materials usually amounts to 0.4—O.Scm g. 

Figure 10.4 Pore volume distribution over effective pore radii calculated from the sorption isotherms for water vapors at limiting wetting angles of (a) 0 and (b) 61.3° for the networks obtained by crosslinking linear polystyrene with p-xylylene dichloride to...

Sorption isotherms for -valeric acid on hypercrosslinked micropor-ous Styrosorbs 1 crosslinked with p-xylylene dichloride, biporous Styrosorb IBP, and, for comparison, macroporous Amberlite XAD-2 are given in Fig. 11.3. Again, one cannot see any correlation between the specific surface area of dry hypercrosslinked sorbents and their capability to take up the acid. Indeed, Styrosorb 1 with X — 25% is a non-porous material when in the dry state, but it swells in water (0.15 mL/g) and, accordingly, retains a noticeable amount of the sorbate. On the other hand, the apparent specific surface area of dry Styrosorb 1 and Styrosorb IBP, both having a 100% degree of crosslinking, are of the same order of magnitude, about lOOOm /g, but the biporous Styrosorb IBP takes up twice as much water as Styrosorb 1 does (2.90 and 1.31 mL/g, respectively) and exhibits an exceptional sorption capacity at equal equilibrium... 

Figure 113 Sorption isotherms for n-valeric acid at 20°C onto Styrosorb 1 (p-xylylene dichloride, XDC) with crosslinking degree of (1) 11, (2) 25, (3) 43, (4) 66, and (5) 100%, (6) Styrosorb IBP (100%), and (7) Amberlite XAD-2. (After [41].)...

Figure 16.2 Dependence of the time of saturation of 50% functional groups with (C4H9)4N ions on the resin water uptake for the sulfonates prepared by crosslinking (1-3) linear polystyrene with (1) 1,4-bis(chloromethyl diphenyl), (2) p-xylylene dichloride, and (3) monochlorodimethyl ether (4) styrene-1 % DVB copolymer crosslinked with 1,4-chloromethyl diphenyl (5) sulfonates based on conventional styrene-DVB copolymers numbers denote the degree of crosslinking. (After [371].)...

Figure 16.5 Sorption isotherms at 25°C of vapors of (1) n-hexane, (2) acetone, (3) methanol, and (4, 5) water onto (1-4) sulfonated Styrosorb 1 crosslinked with p-xylylene dichloride to 100% and onto (5) cation exchanger KU-23, both taken in H+ form. (After [381].)...

Figure 5.16 Synthesis of PBl in PPA and cross-linking of PBI by p-xylylene dichloride [34].

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