Dicyclohexylamine

Dicyclohexylamine reacts with sodium MET to yield DCBS rubber accelerator. Nonrubber Uses 

It is commonly used as a chemical intermediate to synthesize insecticides, plasticizers, antioxidants, and corrosion inhibitors. 

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Cleaved with mild base such as piperidine, morpholine or dicyclohexylamine... 

These species are less stable than R88=C=8(Li)-XR in the presence of a sufficiently acidic proton donor, e.g. amtnonia or dicyclohexylamine, they are... 

Monofunctional, cyclohexylamine is used as a polyamide polymerization chain terminator to control polymer molecular weight. 3,3,5-Trimethylcyclohexylamines ate usehil fuel additives, corrosion inhibitors, and biocides (50). Dicyclohexylamine has direct uses as a solvent for cephalosporin antibiotic production, as a corrosion inhibitor, and as a fuel oil additive, in addition to serving as an organic intermediate. Cycloahphatic tertiary amines are used as urethane catalysts (72). Dimethylcyclohexylarnine (DMCHA) is marketed by Air Products as POLYCAT 8 for pour-in-place rigid insulating foam. Methyldicyclohexylamine is POLYCAT 12 used for flexible slabstock and molded foam. DM CHA is also sold as a fuel oil additive, which acts as an antioxidant. StericaHy hindered secondary cycloahphatic amines, specifically dicyclohexylamine, effectively catalyze polycarbonate polymerization (73). 

For binder preparation, dilute hydrochloric or acetic acids are preferred, because these faciUtate formation of stable silanol condensation products. When more complete condensation or gelation is preferred, a wider range of catalysts, including moderately basic ones, is employed. These materials, which are often called hardeners or accelerators, include aqueous ammonia, ammonium carbonate, triethanolamine, calcium hydroxide, magnesium oxide, dicyclohexylamine, alcohoHc ammonium acetate, and tributyltin oxide (11,12). 

Primary and secondary aliphatic and aromatic amines react readily with thiiranes to give 2-mercaptoethylamine derivatives (Scheme 76) (76RCR25, 66CRV297). The reaction fails or gives poor yields with amines which are sterically hindered e.g. N,iV-dicyclohexylamine) or whose nitrogen atom is weakly basic e.g. N,A/ -diphenylamine). Aromatic amines are less reactive and higher reaction temperatures are usually required for them. The reaction mechanism is Sn2 and substituted thiiranes are attacked preferentially at the least hindered... 

DICLORCAL 50 , dichlorvos, 53 Dicofol, 53 Dicrotophos, 53 Dicyclohexylamine, 53 Dicyclohexylamine nitrite, 53 Dicyclopentadiene, 53 Dicyclopentadienyl bon, 53 Dieldrin, 54 Diepoxybutane, 54 Diethanolamine, 54 Diethoxypropene, 54 Diethyl aluminum chloride, 54 Diethylamine, 54 Diethylaminoethanol, 54... 

One of the advantages of the enamine alkylation reaction over direct alkylation of the ketone under the influenee of strong base is that the major product is the monoalkylated derivative 29,32). When dialkylation is observed, it occurs at the least substituted carbon in contrast to alkylation with base, where the a-disubstituted product is formed. Dialkylation becomes the predominant reaction when a strong organic base is added and an excess of alkyl halide is used (29). Thus 1-N-pyrrolidino-l-cyclo-hexene (28) on treatment with two moles of allyl bromide in the presence of ethyl dicyclohexylamine (a strong organic base which is not alkylated under the reaction conditions) gave a 95 % yield of 2,6-diallylcyclohexanone (29). 

Figure 12.14 Chromatographic analysis of aniline (a) Precolumn chromatogram (the compound represented by the shaded peak is solvent flushed) (b) main column chromatogram without cryotrapping (c) main column chromatogram with ciyottapping. Conditions DCS, two columns and two ovens, with and without ciyottapping facilities columns OV-17 (25 m X 0.32 mm i.d., 1.0 p.m d.f.) and HP-1 (50 m X 0.32 mm, 1.05 p.m df). Peak identification is as follows 1, benzene 2, cyclohexane 3, cyclohexylamine 4, cyclohexanol 5, phenol 6, aniline 7, toluidine 8, nittobenzene 9, dicyclohexylamine. Reprinted with permission from Ref. (20).

Figure 15.11 (a) Total ion clnomatogram of a Grob test mixture obtained on an Rtx-1701 column, and (b) re-injection of the entire clnomatogram on to an Rtx-5 column. Peak identification is as follows a, 2,3-butanediol b, decane c, undecane d, 1-octanol e, nonanal f, 2,6-dimethylphenol g, 2-ethylhexanoic acid h, 2,6-dimethylaniline i, decanoic acid methyl ester ], dicyclohexylamine k, undecanoic acid, methyl ester 1, dodecanoic acid, methyl ester. Adapted from Journal of High Resolution Chromatography, 21, M. J. Tomlinson and C. L. Wilkins, Evaluation of a semi-automated multidimensional gas chromatography-infrared-mass specti ometry system for initant analysis , pp. 347-354, 1998, with permission from Wiley-VCH. 

Hydrogenation of anilines normally gives cyclohexylamines and varying amounts of the coupled products, dicyclohexylamines. The ratio of these products is influenced by temperature, catalytic metal, support, additives, and solvent. It is possible to exert substantial control over the product composition. Coupled products increase with increasing temperature (23). 

In a study on the influence of supports on rhodium, the amount of dicyclohexylamine was found to decrease in the order carbon > barium carbonate > alumina > barium sulfate > calcium carbonate. Plain carbon added to rhodium-on-alumina-catalyzed reactions was found to cause an increase in the amount of dicyclohexylamine, suggesting that carbon catalyzes the formation of the intermediate addition product (59). 

The amount of coupled product was found to depend importantly on the catalytic metal a sequence for increased coupling to dicyclohexylamine was found to be Ru < Rh Pd Pt (59), a sequence that reflects one reason for the industrial preference for rhodium and ruthenium in hydrogenation of anilines. 

Then, 1-(3-acetylthio-2-methylpropanoyl)-L-proline is produced. The 1-(3-acetylthio-3-methyl-propanoyl)-L-proline tert-butyl ester (7.8 g) is dissolved in a mixture of anisole (55 ml) and trifluoroacetic acid (110 ml). After one hour storage at room temperature the solvent Is removed in vacuo and the residue is precipitated several times from ether-hexane. The residue (6.8 g) is dissolved in acetonitrile (40 ml) and dicyclohexylamine (4.5 ml) is added. The crystalline salt is boiled with fresh acetonitrile (100 ml), chilled to room temperature and filtered, yield 3 g, MP 187°C to 188°C. This material is recrystallized from isopropanol [ttlo -67° (C 1.4, EtOH). The crystalline dicyclohexylamine salt is suspended in a mixture of 5% aqueous potassium bisulfate and ethyl acetate. The organic phase is washed with water and concentrated to dryness. The residue is crystallized from ethyl acetate-hexane to yield the 1-(3-acetylthio-2-D-methylpropanoyl-L-proline, MP83°Cto 85°C. 

The final transformation of 15 to 16 was found to exhibit a significant dependence on substituents. 2//-Thiopyran 16a arose spontaneously in 32% yield, while 53% of 16b was obtained together with 41% of its precursor 15b. No formation of thiopyrans 16c and 16d was observed in the case of less substituted hydroxy derivatives 15c and 15d (90BSF446). The preparation of 3-acyl-2//-thiopyrans 17 was reported to be stimulated by dicyclohexylamine (90ZC247). More extensive substituent patterns as well as the use of aqueous NaOH in similar reactions were described (86GEP234674 875456). 

Base peak in dicyclohexylamine and nitroanilines C5H5FeOH, C2F6, (CH2=CHCH2)2Fe (jm/z 110,124,138, and 152 suggest nitriles may observe M - 1 instead of M )... 

Dicyclohexylamine (DCHA), C6HuNHC6Hn, MW = 181.3. Sp. gr = 0.914. Flash point = 219 °F (ASTM D56/closed cup). Available as strongly basic, secondary amine, 99+% commodity product, from manufacturers such as Monsanto Chemical Company and Abbott Laboratories, Inc. 

A further longer term wet lay-up alternative is through the use of volatile corrosion inhibitors (VCIs) such as dicyclohexylamine acetate. These are dissolved in the water at a temperature below 60 °C, and the water is circulated for 4 to 5 hours. The boiler does not need to be completely filled because the VCI migrates to all parts of the boiler and reaches equilibrium in each of the void spaces. With traditional lay-up chemicals, the oxygen scavenger may become depleted easily (which is why the reserve usually is so high) and corrosion protection is quickly lost however, with VCI programs, there is always a volatile buffer available that maintains equilibrium and hence corrosion protection. 

Monsanto. Cyclohexylamine and Dicyclohexylamine. Publication No. 143. Monsanto Chemical Intermediates Co., USA, 1983. 

The formation of dicyclohexylamine as the main product using MVS-derived Pt powders presumably involves dehydrogenation of cyclohexylamine to the corresponding imine with further addition of cyclohexylamine and elimination of NH3 (Scheme 6) [18]. 

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