Propane alkylation with

Methylsuccinic acid has been prepared by the pyrolysis of tartaric acid from 1,2-dibromopropane or allyl halides by the action of potassium cyanide followed by hydrolysis by reduction of itaconic, citraconic, and mesaconic acids by hydrolysis of ketovalerolactonecarboxylic acid by decarboxylation of 1,1,2-propane tricarboxylic acid by oxidation of /3-methylcyclo-hexanone by fusion of gamboge with alkali by hydrog. nation and condensation of sodium lactate over nickel oxide from acetoacetic ester by successive alkylation with a methyl halide and a monohaloacetic ester by hydrolysis of oi-methyl-o -oxalosuccinic ester or a-methyl-a -acetosuccinic ester by action of hot, concentrated potassium hydroxide upon methyl-succinaldehyde dioxime from the ammonium salt of a-methyl-butyric acid by oxidation with. hydrogen peroxide from /9-methyllevulinic acid by oxidation with dilute nitric acid or hypobromite from /J-methyladipic acid and from the decomposition products of glyceric acid and pyruvic acid. The method described above is a modification of that of Higginbotham and Lapworth. ... 

The most stable of all alkyl cations is the tert-butyl cation. Even the relatively stable tert-pentyl and fen-hexyl cations fragment at higher temperatures to produce the tert-butyl cation, as do all other alkyl cations with four or more carbons so far studied. Methane,ethane, and propane, treated with superacid, also yield ten-butyl cations as the main product (see 2-17). Even paraffin wax and polyethylene give the ten-butyl cation. Solid salts of frrf-butyl and rerf-pentyl cations (e.g., MeaC" SbFg ) have been prepared from superacid solutions and are stable below -20°C. ... 

With propene, n-butene, and n-pentene, the alkanes formed are propane, n-butane, and n-pentane (plus isopentane), respectively. The production of considerable amounts of light -alkanes is a disadvantage of this reaction route. Furthermore, the yield of the desired alkylate is reduced relative to isobutane and alkene consumption (8). For example, propene alkylation with HF can give more than 15 vol% yield of propane (21). Aluminum chloride-ether complexes also catalyze self-alkylation. However, when acidity is moderated with metal chlorides, the self-alkylation activity is drastically reduced. Intuitively, the formation of isobutylene via proton transfer from an isobutyl cation should be more pronounced at a weaker acidity, but the opposite has been found (92). Other properties besides acidity may contribute to the self-alkylation activity. Earlier publications concerned with zeolites claimed this mechanism to be a source of hydrogen for saturating cracking products or dimerization products (69,93). However, as shown in reaction (10), only the feed alkene will be saturated, and dehydrogenation does not take place. 

Better results were obtained using (5)-tetrahydro-3-furanyl group as an auxiliary. Regiocontrol and diastereoselectivity improved especially on alkylation with the bulkier 2-iodo-propane in diethyl ether to give 3-isopropyl-2-[(S)-tetrahydro-3-furanyloxy]-l,4-cyclohexadi-ene (2, R1 = 2-propyl) (yield -90% d.r. 80 20). 

Of course, this re-equilibration behavior of two homopoly(amic acids) can be eliminated if one of the components does not exhibit this back reaction. Recombination of different fragments is not possible and stable polyimide precursor blends are accessable [119]. For example, combining a relatively flexible poly(amic acid), hexafluoroisopropylidene diphthalic anhydride (6F)/2,2-bis(4-aminophenoxy-4 -phenyl) propane (BDAF), with a rigid poly(amic alkyl ester), PMDA/p-phenylene diamine (PDA), produced microphase separated polyimide blends as can be interred by the persistence of the... 

The main products formed by the catalytic alkylation of isobutane with ethylene (HC1—AICI3, 25-35°C) are 2,3-dimethylbutane and 2-methylpentane with smaller amounts of ethane and trimethylpentanes.13 Alkylation of isobutane with propylene (HC1—AICI3, — 30°C) yields 2,3- and 2,4-dimethylpentane as the main products and propane and trimethylpentanes as byproducts.14 This is in sharp contrast with product distributions of thermal alkylation that gives mainly 2,2-dimethylbutane (alkylation with ethylene)15 and 2,2-dimethylpentane (alkylation with propylene).16... 

An intermediate aziridinium ion accounts for the observation that alkylations with /S-haloalkyl tertiary amines frequently lead to products with a rearranged carbon-nitrogen skeleton. For example. l-dialkyl-arruno2-jsubstitufc d propanes may form 2-dialkylamino-l-subBtituted... 

In the petroleum industry, catalytic cracking units provide the major source of olefinic fuels for alkylation. A feedstock from a catalytic cracking units is typified by a Ci/C 4 charge with an approximate composition of propane, 12.7% propylene, 23.6% isobmaiie, 25.0% n-bulane, 6.9% isobutylene, 8.8% 1-butylene, 6.9% and 2-butylene, 16.1%. The butylenes will produce alkylates with octane numbers approximately three units higher than those from propylene. 

Description Liquid propylene is mixed with fresh and recycle benzene and then fed to the fixed-bed alkylation reactor (1), where the propylene is completely consumed by alkylation with benzene. Alkylation reactor effluent flows to the depropanizer column (2), where the propane that accompanied the propylene leaves as LPG overhead product. The depropanizer bottoms flows to the benzene column... 

Propylene- -Isobutane Alkylation with Propane Added. The principal... 

One possible advantage of the HF process in propylene/ butylene alkylation is the production of isobutylene from isobutane effected by the hydride-ion transfer to propylene. Isobutylene is the C4 olefinic isomer which produces a significantly higher octane alkylate with HF. This shift, however, converts as much as 22% of the propylene to propane and is a debit. 

Polysulfobetaines derived from alternating styrene-maleic anhydride copolymers 32 are easily prepared by ring opening of the anhydride moiety with 3-dimethylaminopropylamine, imidizing the resulting poly(amic acid) by heating, and alkylation with propane sultone [70-72]. For investigations of structure-property relationships additionally to 32b, the polymers 33 and 34 were synthesized [71]. The ionene-like polymer 33 was prepared... 

To study the relative ease with which various hydrocarbons undergo thermal alkylation with ethylene, a mixture of propane, normal butane, isobutane, and neopentane (9.2 mol % each), 4.6 mol % C2H4, and 17 mol % HC1 were reacted at 399°C and at an initial pressure of 177 atm for 1 hr. The yields of the alkylation products (nC5Hi0 and iC5H10 from C3H6 nC6Hi4 and 3-methyl pentane from nC4Hi0 2-methyl pentane and 2,2-dimethyl butane from isobutane and 2,2-dimethyl pentane from neopentane) were measured and are shown in Table I on a relative basis. 

For example, propane reacts rapidly with CI2 to form a 1 1 mixture of 1 ° and 2° alkyl chlorides. On the other hand, propane reacts with Br2 much more slowly and forms 99% (CH3)2CHBr. 

Aldehyde synthesis 2,4-Dimethylthiazole (1) when treated with n-butyllithium in dry THF and then with benzyl chloride yields 2-(2-phenylethyl)-4-methylthiazole (2) in 94% yield. This product is then alkylated with trimethyloxonium fluoroborate and reduced with sodium borohydride to give 2-(2-phenylethyl)-3,4-dimcthylthiazolidine (3) in high yield. The final step is hydrolysis using mercuric chloride as catalyst 3-phenyl-propanal (4) is obtained in 60% yield. 

In addition 1,3-dithians can be converted into carbonyl compounds thus, l,3dithiacyclohexane (18) (obtained by condensation of propane-1,3-dithiol and formaldehyde) can be alkylated with 3-chloroiodopropane (iodine is the more reactive halide and is selectively displaced) to yield eventually cyclobutanone (19) by the sequence shown in Scheme 4. This sequence shows the stabilising influence of the two adjacent... 

Several points need to be emphasized. Eirst, the /-CgHis (frequently indicated in the literature as TMP) is really a mixture of C5-C16 isoparaffins, often with RON values in the 93-94 range. This mixture (or alkylate) is formed basically by mechanism 2 reactions. Second, when n-olefins (propylene, n-butenes, and n-pentenes) are used, the light n-paraffins formed are propane, n-butane, or n-pentane, respectively none are suitable in the gasoline pool. Third, isobutane consumption per production of a given quantity of alkylate is often increased by 6-10% when HE is employed because of the importance of mechanism 4, as compared to little or most likely no importance for alkylations with sulfuric acid. Eourth, C5 olefins are not usually used in the feedstocks when HE is the catalyst because of the large amounts of isopentane and n-pentane produced further, isobutane consumption increases. 

Use of beta zeolite catalyst does not require the benzene feed to be clay treated prior to use in alkylation service. Some of the unsaturated material in the benzene can lead to the formation in the alkylation reactors of polycyclic-aromatic material which will get preferentially trapped in some zeolites having relatively small-sized pores. This can lead to increased deactivation rates in such small-pore zeolites. Beta zeolite s large pore structure makes it possible to more easily handle this polycyclic-aromatic material and as a result does not require further treatment of the benzene feed to remove unsaturated material. In addition, alpha-methylstyrene (AMS) is produced by alkylation of benzene with methylacetylene or propadiene. Some of the AMS alkylates with benzene, forming diphenyl-propane, a heavy aromatic that leaves the unit with the DIPB column bottoms. 

These compounds are prepared starting from chloroace-tic acid or its ethyl ester. For chains longer than acetic, cya-noethylation and hydrolysis of the nitrile obtained leads to the propionic chain, alkylation with ethyl 4-bromobutyrate and saponification leads to the butyric chain. The propane-sulfonic chains are particularly accessible by means of ring opening of propane-sultone. 

Mizzoni et al. [53] have described the synthesis of cyproquinate (54) and related anticoccidial agents. The method is very similar to that of buquinolate (51) given in scheme 7. Catechol (115) is alkylated with chloro- or bromomethylcyclo-propane to give 120, which is converted in to 54 following the reaction sequence outlined in scheme 8. 

Continuous Friedel-Crafts alkylation, with high selectivity, of mesitylene and ani-sole with propene or propan-2-ol in scCsHe or SCCO2 using a heterogeneous poly-siloxane solid acid catalyst (Deloxan, ASP 1/7) is described by Poliakoff et al. [52] (see Chapter 12). No comparison was made with the continuous alkylation in a conventional solvent and it is, therefore, diffiadt to judge the technical potential of this approach. 

In the case of propane it is necessary to take into account the possibility of the formation of the n- and i-propyl platinum complexes. An analysis of deuteropropane distribution makes it possible to determine the relative rates of platinum(II) reactions with primary and secondary carbon atoms. For this purpose the distribution of deuteropropanes in the case of platinum alkylation with n-PrHgBr and -prHgBr was investigated. The distribution of the deuteropropanes obtained by the H-D exchange of propane coincides with that detected for n-PrPt- and f-PrPt-derivatives if we accept that they are initially formed with a relative probability of 0.75 and 0.25, respectively. Taking into consideration that the propane molecule contains six primary and two secondary C-H bonds, it may be concluded that the selectivity... 

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