Dispersion Halogenation

Cationic Starches. The two general categories of commercial cationic starches are tertiary and quaternary aminoalkyl ethers. Tertiary aminoalkyl ethers are prepared by treating an alkaline starch dispersion with a tertiary amine containing a P-halogenated alkyl, 3-chloto-2-hydtoxyptopyl radical, or a 2,3-epoxypropyl group. Under these reaction conditions, starch ethers are formed that contain tertiary amine free bases. Treatment with acid easily produces the cationic form. Amines used in this reaction include 2-dimethylaminoethyl chloride, 2-diethylaminoethyl chloride, and A/-(2,3-epoxypropyl) diethylamine. Commercial preparation of low DS derivatives employ reaction times of 6—12 h at 40—45°C for complete reaction. The final product is filtered, washed, and dried. 

Reactions of the hydrocarbon chain in alkanoic acids include a-sulfonation and halogenation (51—54). The a-sulfonated fatty ester salts have excellent lime-dispersing properties and are valuable surface-active agents. 

Cl Disperse Blue 87 (107) and related dyestuffs are also prepared from l-oxo-3-imino-4,7-diamino-5,6-phthaloyhsoiQdoline [13418-50-3] (111) by alkylation with corresponding alkyl haUdes (122), sulfonic esters (123), or alkyl amines (124), ie, X of RX = halogen, -toluenesulfonyloxy, or NH2. 

Substituted Anthraquinones. Commercially important blue disperse dyes are derived from 1,4,5,8-substituted anthraquiaones. Among them, diaminodihydroxyanthraquiaone derivatives are most important in view of their shades and affinity. Representative examples are Cl Disperse Blue 56 [31810-89-6] (11) Cl 63285) (126), and Cl Disperse Blue 73 (113) (115). Introduction of a halogen atom ortho to the amino group improves affinity and lightfastness. 

In the 1960s materials became available which are said to have been obtained by chlorination at lower temperatures. In one process the reaction is carried out photochemically in aqueous dispersion in the presence of a swelling agent such as chloroform. At low temperatures and in the presence of excess chlorine the halogen adds to the carbon atom that does not already have an attached chlorine. The product is therefore effectively identical with a hypothetical copolymer of vinyl chloride and symmetrical dichloroethylene. An increase in the amount of post-chlorination increases the melt viscosity and the transition temperature. Typical commercial materials have a chlorine content of about 66-67% (c.f. 56.8% for PVC) with a Tg of about 110% (c.f. approx. 80°C for PVC). 

It would follow that halogenated hydrocarbons would provide much stronger dispersive interactions than a methylene group, a fact that has been well established in both GC and LC. In conclusion it can be said. 

The most prevalent approach to achieve long-lasting and nonstaining ozone protection of rubber compounds is to use an inherently ozone-resistant, saturated backbone polymer in blends with a diene rubber. The ozone-resistant polymer must be used in sufficient concentration (minimum 25 phr) and must also be sufficiently dispersed to form domains that effectively block the continuous propagation of an ozone-initiated crack through the diene rubber phase within the compound. Elastomers such as ethylene-propylene-diene terpolymers, halogenated butyl mbbers, or brominated isobutylene-co-para-methylstyrene elastomers have been proposed in combination with NR and/or butadiene rubber. 

Moreover, it was shown that the presence of Hal Hal interactions between the partially oxidized molecules also contribute to the electronic delocalization. Indeed, the presence of non-zero atomic coefficients on the halogen atoms in the HOMO of EDT-TTF-Br2 or EDT-TTF-I2 [66], together with the short Hal Hal contacts, leads to a sizeable increase of the band dispersion and stabilizes a rare (V structure through the side-by-side arrangement of the inversion-centred dyads connected by Hal- Hal interactions. Both 13 salts are semiconductors with room temperature conductivities around... 

In nature, the halogens exist as nonpolar diatomic molecules. London dispersion forces are the only forces of attraction acting between the molecules. These forces increase with increasing molecular size. 

The strength of the London dispersion forces becomes stronger with increased polarizability, so larger molecule (or atoms) form stronger bonds. This observation helps explain the trends in physical state of the Group VII(b) halogens I2 is a solid, Br2 is a liquid, and Cl2 and L2 are gases. 

Table 3.48 Structure and heat fastness of halogenated phenylazo disperse dyes on polyester [190]...

---