Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Phosphites primary

Similar carbonylations can be effected by treatment of transition metal <7-alkyls with ligands other than carbon monoxide, e.g. triphenyl phosphine, phosphites, primary amines or iodide ion ... [Pg.241]

The primary use for 2,4-di-/ f2 -butylphenol is in the production of substituted triaryl phosphites. 2,4-Di-/ f2 -butylphenol reacts with phosphoms trichloride typically using a trialkylamine or quaternary ammonium salt as the catalyst. Hydrogen chloride is formed and either complexed with the amine or Hberated as free hydrogen chloride gas forming the phosphite ester, tris(2,4-di-/ f2 -butylphenyl)phosphite [31570-04-4] (58). The phosphite-based on... [Pg.68]

When two antioxidants are used together, a synergistic improvement in activity usually results. Synergism can arise from three combinations (1) homosynergism — two chemically similar antioxidants (for instance, two hindered phenols) (2) autosynergism — two different antioxidants functions that are present in the same molecule (3) heterosynergism — the cooperative effect between mechanistically different classes of antioxidants, such as the combined effect of primary and secondary antioxidants. Thus, combinations of phenols and phosphites are widely used to stabilize synthetic rubbers. [Pg.643]

It is a reaction of wide scope both the phosphite 1 and the alkyl halide 2 can be varied. Most often used are primary alkyl halides iodides react better than chlorides or bromides. With secondary alkyl halides side reactions such as elimination of HX can be observed. Aryl halides are unreactive. [Pg.15]

The deoxygeneration of nitroarenes by trivalent phosphorus compounds in the presence of amines is a useful route to 3/f-azepin-2-amines (cf. compounds 32, Section 3.1.1.4.2.2.). Subsequently, it has been shown, by carrying out the reaction in strongly basic solution, that the process can be extended to the synthesis of 1H-. 3H- and 5//-2-benzazepines from nitronaph-thalenes 43 For example, 1-nitronaphthalenes 3 with dimethyl phosphite in the presence of sodium methoxide and a primary or secondary aliphatic amine, yield the dimethyl 5//-2-ben-zazepin-3-yl phosphonates 4 accompanied, in some cases, by the isomeric 3//-2-bcnzazepin-3-yl phosphonates 5. [Pg.254]

Sulfonic esters are most frequently prepared by treatment of the corresponding halides with alcohols in the presence of a base. The method is much used for the conversion of alcohols to tosylates, brosylates, and similar sulfonic esters. Both R and R may be alkyl or aryl. The base is often pyridine, which functions as a nucleophilic catalyst, as in the similar alcoholysis of carboxylic acyl halides (10-21). Primary alcohols react the most rapidly, and it is often possible to sulfonate selectively a primary OH group in a molecule that also contains secondary or tertiary OH groups. The reaction with sulfonamides has been much less frequently used and is limited to N,N-disubstituted sulfonamides that is, R" may not be hydrogen. However, within these limits it is a useful reaction. The nucleophile in this case is actually R 0 . However, R" may be hydrogen (as well as alkyl) if the nucleophile is a phenol, so that the product is RS020Ar. Acidic catalysts are used in this case. Sulfonic acids have been converted directly to sulfonates by treatment with triethyl or trimethyl orthoformate HC(OR)3, without catalyst or solvent and with a trialkyl phosphite P(OR)3. ... [Pg.576]

Salts of dithiocarbamic acid can be prepared by the addition of primary or secondary amines to carbon disulfide. This reaction is similar to 16-9. Hydrogen sulfide can be eliminated from the product, directly or indirectly, to give isothiocyanates (RNCS). Isothiocyanates can be obtained directly by the reaction of primary amines and CS2 in pyridine in the presence of DCC. ° In the presence of diphenyl phosphite and pyridine, primary amines add to CO2 and to CS2 to give, respectively, symmetrically substituted ureas and thioureas ... [Pg.1192]

Olefination Reactions Involving Phosphonate Anions. An important complement to the Wittig reaction involves the reaction of phosphonate carbanions with carbonyl compounds 253 The alkylphosphonic acid esters are made by the reaction of an alkyl halide, preferably primary, with a phosphite ester. Phosphonate carbanions are generated by treating alkylphosphonate esters with a base such as sodium hydride, n-butyllithium, or sodium ethoxide. Alumina coated with KF or KOH has also found use as the base.254... [Pg.164]

The OSM MAP can be effectively applied to most of the organic additives for polyolefins. Its validity has been tested by comparing the OSM with traditional reflux extraction procedures for primary AOs (phenols), secondary AOs (aliphatic and aromatic phosphites ... [Pg.111]

Wieboldt et al. [560] have described SFE-SFC-FTIR analysis of hindered phenol primary antioxidants and phosphite secondary antioxidants in PE. SFE is more selective for the lower-range low-MW polymer than Soxhlet-type extraction. This yields a chromatogram with less interference from low-MW polymer peaks in the region where the additive components elute. As a result, SFE appears to be a better choice than Soxhlet-type extraction for the selective removal of additives from flaked polymer. SFE and dissolution/precipitation methods were compared for a PVC/stabiliser system [366]. [Pg.137]

Reduction of azides is a classical approach to primary amine synthesis. Treatment of 17 with sodium azide in DMF or in THF/H2O mixtures in the presence of phase transfer catalysts effects a quantitative conversion to the corresponding polymeric azide, 27. Recently the reduction of azides to primary amines via hydrolysis of iminophosphoranes produced by interaction of the azide with triethyl phosphite was reported.30 Application of this technique to the azidomethyl polymer, 27, as shown below, failed to produce a soluble polyamine. [Pg.20]

In addition to clusterification, ligand substitution also occurs for Fe(CO)5, and in fact for most metal carbonyls. This has proved useful as a mechanistic probe of the reactive species formed during cavitation. Sonica-tion of Fe(CO)5 in the presence of phosphines or phosphites produces Fe(CO)5 L (n = 1,2, and 3). The ratio of these products is independent of length of sonication the multiply substituted products increase with increasing initial [L] Fe(CO)4L is not sonochemically converted to Fe(CO)3L2 on the timescale of its production from Fe(CO)5. These observations are consistent with the same primary sonochemical event... [Pg.98]

From phosphorus trichloride, benzyl alcohol and 2 mol. of a tertiary base, dibenzyl hydrogen phosphite (XIV), is obtained which on treatment with chlorine or a chlorinating agent (e.g. sulphuryl chloride)4 gives the phosphorochloridate (XV). Although not isolated, (XV) is almost certainly obtained by treatment of (XIV) with a polyhalogen hydrocarbon because reaction in the presence of an alcohol or of a primary or secondary amine gives a triester (XVI) or a phosphoramidate. [Pg.119]

A convenient one-pot procedure for the conversion of alcohols into primary amines has been reported. The alcohol is converted into the corresponding alkyl halide by the action of bromotrichloromethane/triphenylphosphine and the product is treated successively with sodium azide, triethyl phosphite, hydrochloric acid and sodium hydroxide (equation 20)55, cf. equation 14. [Pg.542]

Borg-Warner Chemicals EYI-OTS-0785-0422 ELWP. Sequence D. Primary Eye Irritation Tests of Triphenyl Phosphite in Rabbits. Washington, DC, US Environmental Protection Agency, Office of Taxic Substances, 1980... [Pg.720]

Unwanted degradation and oxidation processes can be avoided or at least suppressed for some time either by structural modiflcation of the polymer or by special additives. In practice, the addition of so-called antioxidants is particularly effective. Chemical substances that slow down oxidations and the following aging phenomena serve for this purpose. Antioxidants are sufficiently effective even in concentrations below 1 wt% and are added as early as possible to the polymer to be protected, e.g., already during the drying of powdery polymeric materials or during the preparation of granulates. Some of the most important so-called primary antioxidants are sterically hindered phenols and secondary aromatic amines secondary antioxidants are thioethers as well as phosphites and phosphonites. [Pg.357]


See other pages where Phosphites primary is mentioned: [Pg.491]    [Pg.263]    [Pg.68]    [Pg.85]    [Pg.1026]    [Pg.250]    [Pg.8]    [Pg.636]    [Pg.700]    [Pg.774]    [Pg.780]    [Pg.161]    [Pg.333]    [Pg.250]    [Pg.242]    [Pg.251]    [Pg.243]    [Pg.720]    [Pg.238]    [Pg.510]    [Pg.673]    [Pg.732]    [Pg.139]    [Pg.202]    [Pg.571]    [Pg.85]    [Pg.673]    [Pg.732]    [Pg.872]    [Pg.877]   
See also in sourсe #XX -- [ Pg.911 ]




SEARCH



© 2024 chempedia.info