Alternation of melting points in homologous series of long‐chain compounds

Larsson, Karl-Johan

doi:10.1007/bf02641187

Cited by 71 publications

(38 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Although these ideas now seem discordant with our views on covalent bonding (Burrows 1992), they perhaps relate to resonance within covalence bonding (Muller and Carl 2006). Larsson (1966) suggested that packing in the planes containing the end groups explained the effect. An increase in packing density will increases the intermolecular interactions, notably Van der Waals's forces.…”

Section: Odd-even Effectmentioning

confidence: 96%

“…Burrows 1992). Cappa et al (2007) and Larsson (1966) approached this from an atmospheric science perspective in relation the vapour pressure of (C 4 -C 10 ) dicarboxylic acids. The odd-even effect is often observed with longer chain compounds particularly in terms of the triple point of the mono-carboxylic acids and the Kraft temperature which relates to surfactant properties.…”

Section: Odd-even Effectmentioning

confidence: 98%

See 1 more Smart Citation

The Odd–Even Behaviour of Dicarboxylic Acids Solubility in the Atmospheric Aerosols

Rozaini

Brimblecombe

2008

Water Air Soil Pollut

View full text Add to dashboard Cite

The solubility and the enthalpy of dicarboxylic acids have been determined in water at intervals between 278.5 and 543.5 K. At 298.15 K, the values derived were: Δ sol H m (m=1.33 mol kg −1 )=29.80 kJ mol −1 for oxalic acid; Δ sol H m (m=16.03 mol kg −1 )= 12.82 kJ mol −1 for malonic acid; Δ sol H m (m=0.75 mol kg −1 )=28.20 kJ mol −1 for succinic acid; Δ sol H m (m=8.77 mol kg −1 )=48.01 kJ mol −1 and Δ sol H m (m= 0.17 mol kg −1 )=40.30 kJ mol −1 for glutaric and adipic acid respectively. The solubility value exhibits a prominent odd-even effect with respect to terms with even number of carbon atoms with the odd carbon numbers showing much higher solubility. Observations made in the atmospheres suggest that this odd-even effect may have implications for the relative abundance of these acids in aerosols.

show abstract

Section: Odd-even Effectmentioning

confidence: 96%

Section: Odd-even Effectmentioning

confidence: 98%

The Odd–Even Behaviour of Dicarboxylic Acids Solubility in the Atmospheric Aerosols

Rozaini

Brimblecombe

2008

Water Air Soil Pollut

View full text Add to dashboard Cite

show abstract

“…When the long alkyl/acyl chains are tilted with respect to methyl end group planes then the van der Waals interactions between methyl groups from opposite layers are usually different for the even-and odd chain length series. 24,25 Therefore, odd-even alternation is clearly observed when the alkyl chain packing is inclined with respect to the methyl end planes, but not when they are packed perpendicular to the methyl end planes. 14,25 The odd-even alternation in the calorimetric properties of dry and hydrated NAAEs as observed here suggests that the acyl and/or alkyl chains are tilted with respect to the respective methyl end planes in them.…”

Section: Chain Length Dependence Of Transition Enthalpy and Transitiomentioning

confidence: 92%

Differential scanning calorimetric and powder X-ray diffraction studies on a homologous series of N-acyl-L-alanine esters with matched chains (n = 9-18)

Sivaramakrishna

Swamy

2015

J Chem Sci

View full text Add to dashboard Cite

A homologous series of two chain derivatives of L-alanine, namely N -acyl L-alanine alkyl esters (NAAEs), bearing matched, saturated, acyl and alkyl chains (n = 9-18) have been synthesized. The thermotropic phase transitions and supramolecular structure of NAAEs were investigated by differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). Results obtained from DSC studies indicate that the transition temperatures (T t ), enthalpies ( H t ) and entropies ( S t ) exhibit odd-even alternation with compounds bearing odd acyl and alkyl chains showing higher values of T t , H t and S t as compared to NAAEs with even acyl and alkyl chains. However, the transition enthalpies and entropies of the odd-and even chain length series independently exhibit a linear dependence on the chain length. The d-spacings obtained from PXRD increase linearly with chain length with an increment of 1.76 Å/CH 2 , suggesting that NAAEs adopt either a tilted bilayer structure or a bent structure. The present results provide a thermodynamic and structural basis for investigating the interaction of NAAEs with other membrane lipids, which in turn can shed light in understanding how they can enhance the transdermal permeability of stratum corneum.

show abstract

“…(3 Â 30 ml) and brine (total 90 ml); dried (Na 2 SO 4 ), and evaporated. FC (CH 2 Cl 2 / H 9.58,N 4.19;found: C 56.26,H 9.70,ethoxy]acetic Acid (Dithiodipropane-3,1-diyl) Ester (11). According to [25], a mixture of 7 (4.58 g, 25.7 mmol), CHCl 2 OMe (3.7 g, 32.1 mmol) and ZnCl 2 (0.18 g, 1.2 mmol) was stirred at r.t. for 1 h and refluxed 1 h under N 2 .…”

Section: Experimental Partmentioning

confidence: 99%

“…The (dithiodialkanediyl)bis[phthalimides] 4a ± f were obtained by treatment of (bromoalkyl)phthalimides 3a ± f with Na 2 S 2 O 3 and oxidation of the Bunte salts with I 2 in 70 ± 80% yield. The compounds 3b ± f show the well-known behavior of alternating melting points for homologuous series of substituted alkanes [10] [11]. The stable and easily isolated (dithiodialkanediyl)-bis[ammonium chlorides] 5a ± f were obtained in 60 ± 80% yield by treatment of the phthalimides 4a ± f with hydrazine followed by addition of hydrochloric acid.…”

mentioning

confidence: 99%

Synthesis ofω-Substituted Alkanethiols and (Bromomethyl)methylthiomalonates

Pfammatter¹,

Siljegovic²,

Darbre³

et al. 2001

HCA

View full text Add to dashboard Cite

Several multifunctional derivatives of methylthiomalonic acid ( 2-(thiocarboxy)acetic acid), i.e. 20a, b, 21, 22a, b, and 24, were prepared from thiols bearing a functionalized head group, i.e. from 9a, b, 12, and 16d, f (Schemes 4 and 5). The association constants of the two dithio podands 8b and 11 with K were determined.Introduction. ± For development of models of the coenzyme-B 12 -dependent methylmalonyl-CoA mutase, we have prepared a variety of (bromomethyl)methylthiomalonates ( 2-(bromomethyl)-2-methyl-3-oxo-3-(alkylthio)propanoates) with head groups for molecular recognition. These model substrates are to be used to investigate the efficiency of the methylmalonyl-succinyl rearrangement when the substrate and the vitamin-B 12 molecule are held together by noncovalent interactions. The concept of enhancing the rearrangement by peripheral association of appropriate groups is based on the idea that enzymes or enzyme-coenzyme complexes must recognize their substrates and associate with them through noncovalent bonds to provide the orientation and proximity necessary for catalysis [1 ± 4]. Hitherto, we have reported a hydrophobic model, where lipophilic alkane chains are used for the association between the methylmalonyl moiety and the vitamin B 12 , appropriately modified in the periphery, and two models based on association in aprotic solvents between an A´T and a C´G base pair, respectively [5 ± 8]. Enhanced rearrangement has been observed for the hydrophobic and the A´T mode [5] [6]. In further persuit of vitamin-B 12 -related concepts for molecular recognition between methylmalonyl substrates and the catalyst, we considered the association between polyether (podand) units mediated by cations as well as the interaction between carbohydrate-derived units. We report here the preparation of alkanethiols bearing a polyether moiety or a pentahydroxyhexanoyl head group as well as the efficient synthesis of thioesters thereof. First results for the binding constants between two polyethers with alkali cations are reported.

show abstract

Alternation of melting points in homologous series of long‐chain compounds

Cited by 71 publications

References 20 publications

The Odd–Even Behaviour of Dicarboxylic Acids Solubility in the Atmospheric Aerosols

The Odd–Even Behaviour of Dicarboxylic Acids Solubility in the Atmospheric Aerosols

Differential scanning calorimetric and powder X-ray diffraction studies on a homologous series of N-acyl-L-alanine esters with matched chains (n = 9-18)

Synthesis ofω-Substituted Alkanethiols and (Bromomethyl)methylthiomalonates

Contact Info

Product

Resources

About