Big Chemical Encyclopedia

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

Articles Figures Tables About

Diamines, tertiary

Anti-stripping agents are chemical substances that have a similar composition to emulsifiers and are divided into (a) anionic type, such as organic acids (creosote) and fatty acids (oleic acid, stearic acid, pine pitch, etc.), and (b) cationic type, such as amines (simple amines, diamines, tertiary amines, polyamines and imidazolines) and salts of quaternary ammonium. [Pg.133]

Clearly, the use of diamine 4.43 as a coordinating auxiliary is not successful. However, we anticipated that, if the basicity of the tertiary amine group of the diamine could be reduced, the elimination reaction will be less efficient. We envisaged that replacement of the tertiary amine group in 4.43 by a pyridine ring might well solve the problem. [Pg.116]

Formic acid forms esters with primary, secondary, and tertiary alcohols. The high acidity of formic acid makes use of the usual mineral acid catalysts unnecessary in simple esterifications (17). Formic acid reacts with most amines to form formylamino compounds. With certain diamines imida2ole formation occurs, a reaction that has synthetic utiHty (18) ... [Pg.503]

Conditions cited for Rh on alumina hydrogenation of MDA are much less severe, 117 °C and 760 kPA (110 psi) (26). With 550 kPa (80 psi) ammonia partial pressure present ia the hydrogenation of twice-distilled MDA employing 2-propanol solvent at 121°C and 1.3 MPa (190 psi) total pressure, the supported Rh catalyst could be extensively reused (27). Medium pressure (3.9 MPa = 566 psi) and temperature (80°C) hydrogenation usiag iridium yields low trans trans isomer MDCHA (28). Improved selectivity to aUcychc diamine from MDA has been claimed (29) for alumina-supported iridium and rhodium by iatroduciag the tertiary amines l,4-diazabicyclo[2.2.2]octane [280-57-9] and quiaucHdine [100-76-5]. [Pg.209]

Cycloahphatics capable of tertiary carbocation formation are candidates for nucleophilic addition of nitriles. HCN in strong sulfuric acid transforms 1-methyl-1-cyclohexanol to 1-methyl-1-cyclohexylamine through the formamide (47). The terpenes pinene (14) [2437-95-8] and limonene [5989-27-5] (15) each undergo a double addition of HCN to provide, after hydrolysis, the cycloahphatic diamine 1,8-menthanediamine (16) (48). [Pg.210]

Castor esters have been found to be nonirritating and noncomedogenic to the skin. Cetyl ricinoleate was found to be an effective noncomedogenic moisturizer (118). Castor-based quaternaries prepared by reaction of a castor fatty acid and a tertiary diamine are used for hair care. The ricinoleic quaternium is incorporated into clear shampoo formulations for foam enhancement and conditioning (119,120). [Pg.156]

Another type of bifunctional catalysis has been noted with a,cn-diamines in which one of the amino groups is primary and the other tertiary. These substituted diamines are from several times to as much as 100 times more reactive toward imine formation than similar monofunctional amines. This is attributed to a catalytic intramolecular proton transfer. [Pg.494]

In actual practice, catalysts are usually employed to catalyze the isocyanate/ alcohol reaction at room temperature. Typical catalysts for this reaction are the tin(IV) salts, e.g., dibutytin dilaurate, or tertiary amines, such as triethylene diamine [2]. [Pg.762]

The spin adducts of free radicals and MNP or DMPO were observed by means of an ESR spectrometer. The data of hyperfine splitting constants were compiled in Tables 9 and 10 [40-42,44,45]. ESR studies on the initial free radicals revealed that the monoalkylamino radical RHN-, dialkylamino radical R2N-, and aminomethyl radical -CH2N< or aminoethylidene radical >N( CHCH3) were obtained from the corresponding primary, secondary, and cyclic tertiary amine. In case of a tertiary diamine such as TMEDA, formation of... [Pg.233]

Filmers are based on primary, secondary, or tertiary monoamines or diamines and contain alkyl chains with from 8 to 22 carbons. The most prominent material is the 18-carbon-chain aliphatic monoalkylamine, octadecylamine (ODA). [Pg.537]

This reaction is simple and qualitative36 37 the diamine can be both an aromatic and an aliphatic diamine. With this method, even star-shaped PAs have been synthesized.37 Solution polymerization from acid chlorides and aliphatic diamines is more difficult due to the strong basicity of the aliphatic amine groups. Acid binders which have been used with aliphatic diamines are the tertiary amines with high kb values these include dimethylbenzylamine and diisopropylethylamine.4 38... [Pg.157]

Moreover, a dramatic increase of the reaction rate was observed when the coupUng of aromatic imines mediated by samariiun diiodide was carried out in the presence of both water and a tertiary amine or tetramethylethylene-diamine (TMEDA) [29], causing the almost instantaneous formation of the 1,2-diamine, although with undetermined diastereoselectivity. Similarly, the samarium diiodide promoted reductive coupling of iminiiun ions formed in situ by reacting ahphatic aldehydes with secondary amines and benzotriazole occurred at temperatures as low as - 70 °C [30]. Even in this case a mixture of diastereomers with undetermined ratio was obtained nevertheless, the item of diastereoselectivity induced by a chiral amine (auxiliary) is worthy of investigation. [Pg.13]

After finding the right combination for the diamine linkers, Yus et al. tried to determine whether it was compulsory to use two isoborneol-10-sulfonamide moieties. In this context, these authors have prepared the ligand depicted in Scheme 4.24 by reaction of the best amine linker, trani-cyclohexane-1,2-diamine, with camphorsulfonyl chloride and then with methanesulfonyl chloride, followed by reduction with AlH(i-Bu)2 and then hydrolysis.When this new ligand was involved in the enantioselective addition of ZnEt2 to acetophenone, the expected tertiary alcohol was obtained in excellent yield and enantioselectivity of 96% ee, as shown in Scheme 4.24. According to this result, the authors concluded that the second isoborneol unit seemed not to be necessary to obtain a high enantioselectivity. [Pg.174]

The company Buckman Laboratories came out for the first time some 25 years ago with Polyquats. They were obtained by a reaction with a tertiary amine TMEDA (tetramethylethylene diamine), where the methyl groups can react easily with an ether. [Pg.133]

The history of dendrimer chemistry can be traced to the foundations laid down by Flory [34] over fifty years ago, particularly his studies concerning macro-molecular networks and branched polymers. More than two decades after Flory s initial groundwork (1978) Vogtle et al. [28] reported the synthesis and characterization of the first example of a cascade molecule. Michael-type addition of a primary amine to acrylonitrile (the linear monomer) afforded a tertiary amine with two arms. Subsequent reduction of the nitriles afforded a new diamine, which, upon repetition of this simple synthetic sequence, provided the desired tetraamine (1, Fig. 2) thus the advent of the iterative synthetic process and the construction of branched macromolecular architectures was at hand. Further growth of Vogtle s original dendrimer was impeded due to difficulties associated with nitrile reduction, which was later circumvented [35, 36]. This procedure eventually led to DSM s commercially available polypropylene imine) dendrimers. [Pg.32]

A detailed study of the role of the base in the formation of 2-isoxazolines by condensation of primary nitro compounds with alkenes in the presence of the tertiary diamine 1,4-diazabicyclo[2.2.2]octane (DABCO) was published <06EJO4852 06EJ03016>. [Pg.293]

In summary, the reaction of osmium tetroxide with alkenes is a reliable and selective transformation. Chiral diamines and cinchona alkakoid are most frequently used as chiral auxiliaries. Complexes derived from osmium tetroxide with diamines do not undergo catalytic turnover, whereas dihydroquinidine and dihydroquinine derivatives have been found to be very effective catalysts for the oxidation of a variety of alkenes. OsC>4 can be used catalytically in the presence of a secondary oxygen donor (e.g., H202, TBHP, A -methylmorpholine-/V-oxide, sodium periodate, 02, sodium hypochlorite, potassium ferricyanide). Furthermore, a remarkable rate enhancement occurs with the addition of a nucleophilic ligand such as pyridine or a tertiary amine. Table 4-11 lists the preferred chiral ligands for the dihydroxylation of a variety of olefins.61 Table 4-12 lists the recommended ligands for each class of olefins. [Pg.224]


See other pages where Diamines, tertiary is mentioned: [Pg.146]    [Pg.146]    [Pg.1072]    [Pg.42]    [Pg.243]    [Pg.361]    [Pg.219]    [Pg.223]    [Pg.91]    [Pg.129]    [Pg.130]    [Pg.331]    [Pg.174]    [Pg.116]    [Pg.415]    [Pg.168]    [Pg.302]    [Pg.158]    [Pg.1072]    [Pg.164]    [Pg.342]    [Pg.379]    [Pg.122]    [Pg.201]    [Pg.1]    [Pg.1011]    [Pg.50]    [Pg.127]    [Pg.105]    [Pg.372]    [Pg.157]   
See also in sourсe #XX -- [ Pg.198 ]

See also in sourсe #XX -- [ Pg.846 ]




SEARCH



Chiral tertiary diamines

Complexes tertiary diamine organolithium

Diamines primary-tertiary

Primary-tertiary diamine catalyst, aldol

Primary-tertiary diamine catalysts

Tertiary diamine complexes

© 2024 chempedia.info