C15 C17 Research Articles

Convenient and facile theoretical design strategy to amplify NLO response of N‐doped‐indolo[3,2,1‐jk]carbazole push–pullA‐π‐D‐π‐A switches

AbstractBACKGROUNDNonlinear optical (NLO) materials play a crucial role in various technological fields, making it important to develop strategies that enhance their properties. This research paper focuses on the design strategy to enhance the NLO response of indolo[3,2,1‐jk]carbazole‐based N‐doped fused‐ring electron acceptors as its five new A‐π‐D‐π‐A switches.RESULTSThe chromophores IC1–IC5 were studied for their electronic, NLO, charge transfer, UV–visible and natural bond orbital‐related features. Their energy levels were determined, with IC1 having the highest energy (3.12 eV) and IC5 the lowest energy (1.916 eV). Their corresponding maximum absorption wavelengths (λmax) were determined to range from 398 to 647 nm. Their electronegativity (x), chemical potential (μ), hardness (η), softness (σ) and electrophilicity of the chromophores were also analyzed, having values ranging from 3.00 to 3.47 eV, 47 to −3.0 eV, 0.25 to 1.39 eV, 0.36 to 2.04 eV and 3.23 to 23.81 eV, respectively. The η and σ values indicated the stability and reactivity of the chromophores, with IC1 having the lowest η and highest σ values. IC2 had the highest dipole moment (μtot) (9.23D) and hyperpolarizability (β0) of 10.323 × 10−11 esu, indicating its strong NLO response. Among all, chromophore IC1 demonstrated a robust stabilization energy by its (N1) → (C15–C17)π* transition.CONCLUSIONThe proposed theoretical design strategy successfully amplifies the NLO response of N‐doped‐indolo[3,2,1‐jk]carbazole switches to open up possibilities for the development of advanced NLO materials, paving the way for future applications in photonics, optoelectronics and other emerging technologies. © 2023 Society of Chemical Industry (SCI).

FEATURES OF THE DISTRIBUTION AND COMPOSITION OF ORGANIC COMPOUNDS IN WATER AND BOTTOM SEDIMENTS CHERNAVKA RIVER FLOWING INTO ELTON LAKE

Organic compounds: Corg, lipids, hydrocarbons (HCs) – aliphatic (AHCs) and polycyclic aromatic (PAHs) in suspended particulate matter of surface waters and in bottom sediments of the shallow Chernavka River, which flows into a self-sustaining Elton Lake were studied. High concentrations of organic compounds were found in surface waters: in averaged 692, 80 and 0.79 µg/L for lipids, AHCs, and PAHs respectively. The composition of alkanes in the aqueous suspension corresponded to the weathered oil hydrocarbons. HC transformation occurs here not in the course of sedimentation, but at the water–bottom sediment interface. As a result, the AHC composition of the sediments differed from that of the particulate matter in the presence of planktonogenic low molecular weight homologues of n C15–C17 and a sharp increase in the series of odd high molecular weight alkanes, while the PAH composition differed in the increase in the proportion of naphthalene.

Geochemical characterization and origin of crude oils in the Oriente basin, Ecuador, South America

The Cretaceous oil reservoir located in eastern slope belt of the Oriente basin accounts for most of the discoveries in last decade in Ecuador, which makes the Oriente basin one of the most important oil exploration targets in South America. Crude oil samples (n = 31) in 31 wells together with mudstone and limestone source rocks (n = 18) from Cretaceous Napo Formation in 16 wells were analyzed to evaluate the geochemical characteristics of the oil reservoir oil.Geochemical analyses included measurements of total organic carbon (TOC) content, Rock-Eval Pyrolysis, gas chromatography (GC), and gas chromatography-mass-spectrometry (GC-MS).All the oil samples have pre-uimodal n-alkane distribution dominated by lower molecular weight components (peak at C15–C17) with a small peak at C25–C30. The carbon preference index (CPI) and odd-over-even predominance (OEP) values range between 1.0 and 1.34, and 1.0–1.21 respectively; Pr/Ph ratios range from 0.67 to 1.16; high Pr/n-C17 (0.80–3.47) and Ph/n-C18 ratios (0.82–7.86) values and dominate C27 regular steranes, all these biomarkers show that the oil derived from marine algal material. Furthermore, all oils have similar Terpanes and Steranes distribution shape, peak at C23TT, and low at C22TT (TT = tricyclic terpanes), relative low C22/C21, C24/C23 and C26/C25 tricyclic terpane ratios, higher C27R (R = regular steranes) content than C29R and C28R. These biomarkers demonstrate that all the oils are from same genetic family although they came from different zones. There are two kinds of source rocks in the Oriente basin, shale and argillaceous bioclastic limestone of Napo Formation. These rocks are good-excellent mature according to TOC and Rock-Eval assessment. The two source rocks show obvious different Terpanes and Steranes distribution shape in mz191 and mz217 maps. The Oil-Source correlation analysis demonstrates that the crude oils have similar Terpane and Steranes distribution shape and biomarker value, especially the C27R–C28R–C29R ratio, with argillaceous bioclastic limestone of Napo Formation. This new geochemical data suggests that the argillaceous bioclastic limestone is the major source rock in the Oriente basin. Thus, distribution of this stratigraphic unit should be the key point for future exploration.

Total Synthesis of (±)-Prostratin

Summary Prostratin, a highly complex diterpene natural product, is a pre-clinical candidate in developing a cure for HIV-1 infection and also a potent and selective inhibitor of several tumors. Despite nearly 40 years of progress, prostratin and related natural products still present formidable challenges for synthetic chemists. Here, we report a total synthesis of (±)-prostratin that proceeds in 23 steps from cyclopentadiene. The synthetic strategy includes rapid assembly of the tricyclic core and highly controlled establishment of the densely functionalized C ring, featuring an array of stereoselective transformations including alkoxide-guided 1,4-additions and cyclopropane formation. This work should enable further explorations of chemical and biological spaces based on prostratin and related natural products.

Identification of a small antimycotic peptide produced by Bacillus amyloliquefaciens 6256

Bacillus sp. 6256 is a good biocontrol agent against Botrytis cinerea which caused tomato gray mold disease. Strain 6256 was identified as B. amyloliquefaciens by analysis of its partial gyrB gene sequence. To identify and characterize the antimycotic peptides from the culture broth of the bacterium, the antimicrobial substances produced by B. amyloliquefaciens 6256 were isolated by ammonium sulfate precipitation, Superdex 200 gel filtration chromatography and DEAE anion exchange chromatography. The purified compound was designated as P657. The biological activity of P657 was stable at as high as 100 °C for 20 min and in pH value ranged from 5 to 10. The antimycotic compound was resistant to trypsin and proteinase K, and could completely inhibit spore germination of Botrytis cinerea in vitro. MALDI-TOF-MS analysis results showed the presence of fengycins A (C16–C17) and fengycins B (C15–C17) isoforms in P657.

Effect of Cu promotion on cracking and methanation during the Ni-catalyzed deoxygenation of waste lipids and hemp seed oil to fuel-like hydrocarbons

Deoxygenation of yellow grease and hemp seed oil was studied over 20% Ni/Al2O3 and 20% Ni-5% Cu/Al2O3 catalysts in the presence of H2. In the deoxygenation of 25wt% yellow grease (dissolved in dodecane) both catalysts afforded a liquid product consisting of mainly linear C10–C17 alkanes; however, the Cu-promoted catalyst showed improved selectivity to long chain (C15–C17) hydrocarbons as a result of its lower cracking activity. Analysis of the light hydrocarbon products (C10–C16) showed that cracking mainly occurred via the removal of terminal carbons (with methane formation), although a small amount of internal cracking also occurs based on the presence of C6–C11 in the product mixtures. Similar improvements were also observed in the deoxygenation of 25wt% hemp seed oil, showing that Cu was able to curb cracking even when a highly unsaturated feed was employed. The Cu promotion effect was more pronounced in the deoxygenation of 75wt% yellow grease in which the 20% Ni/Al2O3 catalyst did not yield any liquid products, whereas the 20% Ni-5% Cu/Al2O3 catalyst afforded liquid products consisting of >90% diesel-like hydrocarbons.

Stereoselective synthesis of the C-11 to C-19 segment of macrolactin 3 via a center inversion followed by Oxa-Michael addition approach

GRAPHICAL ABSTRACT

Valorization of Waste Lipids through Hydrothermal Catalytic Conversion to Liquid Hydrocarbon Fuels with in Situ Hydrogen Production

We demonstrate hydrothermal (300 °C, 10 MPa) catalytic conversion of real waste lipids (e.g., waste vegetable oil, sewer trap grease) to liquid hydrocarbon fuels without net need for external chemical inputs (e.g., H2 gas, methanol). A supported bimetallic catalyst (Pt–Re/C; 5 wt % of each metal) previously shown to catalyze both aqueous phase reforming of glycerol (a triacylglyceride lipid hydrolysis coproduct) to H2 gas and conversion of oleic and stearic acid, model unsaturated and saturated fatty acids, to linear alkanes was applied to process real waste lipid feedstocks in water. For reactions conducted with an initially inert headspace gas (N2), waste vegetable oil (WVO) was fully converted into linear hydrocarbons (C15–C17) and other hydrolyzed byproducts within 4.5 h, and H2 gas production was observed. Addition of H2 to the initial reactor headspace accelerated conversion, but net H2 production was still observed, in agreement with results obtained for aqueous mixtures containing model fatty acids and glycerol. Conversion to liquid hydrocarbons with net H2 production was also observed for a range of other waste lipid feedstocks (animal fat residuals, sewer trap grease, dry distiller’s grain oil, coffee oil residual). These findings demonstrate potential for valorization of waste lipids through conversion to hydrocarbons that are more compatible with current petroleum-based liquid fuels than the biodiesel and biogas products of conventional waste lipid processing technologies.

Refikite from Krásno, Czech Republic: a crystal-and molecular-structure study

AbstractThe crystal structure of the organic mineral refikite has been determined. The mineral was found in joints in bark and wood from pine trees in the 'V Borkách' peat deposit near the town of Krásno, Slavkovský les Mountains, western Bohemia, Czech Republic. It forms white to light-yellow polycrystalline crusts or randomly intergrown, transparent, colourless, very thin, acicular crystals up to 0.2–0.5 mm long. Sometimes, colourless-to-white elongated prismatic crystals up to 1–1.5 mm in size were encountered. The mineral is soft (Mohs hardness ∼1) and very brittle, with an uneven fracture. No visible cleavage was discerned. Crystals have a greasy-to-glassy lustre; fine crystal aggregates have a pearly lustre. Refikite, empirical formula C20H34O2 or C19H33COOH, is a derivative of abietic acid. It is orthorhombic, space group P21212, with a = 22.6520(7), b = 10.3328(3), c = 7.6711(2) Å, V = 1795.49(9) Å3, Z = 4. Refikite comprises two closely related compounds based on perhydrophenanthrene. The major component has two axial methyl groups, one terminal carboxylic group and one terminal propan-2-yl (isopropyl) group joined to the three fused rings in the same fashion as in abietic acid. However, the fused ring system is fully reduced (contains single bonds only). In the minor component, the terminal propan-2-yl group is replaced by a propen-2-yl (methylvinyl) group. The crystal structure is stabilized by strong O···H–O hydrogen bonds. High-resolution mass spectroscopy (HRMS) confirmed a molecular mass of 306 and the formula C20H34O2. Hydrogen-1 and carbon-13 nuclear magnetic resonance (NMR) spectroscopy showed the presence of four methyl groups in the major component; infrared (IR), Raman and NMR spectra are consistent with the structure. The HRMS, IR and Raman spectroscopy methods confirmed the presence of a minor component containing the propen-2-yl group replacing the propan-2-yl group. This is also reflected in a shortened C15–C17 single bond metric of 1.468(6) Å shown by single-crystal X-ray analysis. The trivial name of the major component of refikite is tetrahydroabietic acid or abietan-18-oic acid. This work represents the first proof of the existence of abietic acid derivatives as naturally occurring species.

Crustal features of the northeastern South China Sea: insights from seismic and magnetic interpretations

We interpret seven two-dimensional deep-penetration and long-offset multi-channel seismic profiles in the northernmost South China Sea area, which were collected by R/V Marcus G. Langseth during the TAIwan GEodynamics Research (TAIGER) project in 2009. To constrain the crustal characteristics, magnetic inversion and forward magnetic modeling were also performed. The seismic results clearly show tilted faulting blocks in the upper crust and most of the fault plane connects downward to a quasi-horizontal detachment as its bottom in the south of the Luzon-Ryukyu transform plate boundary. North of the plate boundary, a small-scale failed rifted basin (minimum 5 km in crustal thickness) with negative magnetization probably indicates an extended continental origin. Significant lower crustal material (LCM) was imaged under a crustal fracture area which indicated a continent and ocean transition origin. The thickest LCM (up to 6.5 km) is located at magnetic isochron C15 that is probably caused by the magma supply composite of a Miocene syn-rift volcanic event and Pliocene Dongsha volcanic activity for submarine volcanoes and sills in the surrounding area. The LCM also caused Miocene crustal blocks to be uplifted reversely as 17 km crustal thickness especially in the area of magnetic isochron C15 and C16. In addition, the wide fault blocks and LCM co-existed on the magnetic striped area (i.e. C15–C17) in the south of the Luzon-Ryukyu transform plate boundary. Magnetic forward modeling suggests that the whole thick crustal thickness (>12 km thick) needs to be magnetized in striped way as oceanic crust. However, the result also shows that the misfit between observed and synthetic magnetic anomaly is about 40 nT, north of isochron C16. The interval velocity derived from pre-stack time migration suggests that the crust is composed of basaltic intrusive upper crust and lower crustal material. The crustal nature should refer to a transition between continent and ocean. Thus, the magnetic reversals may be produced in two possible ways: basaltic magma injected along the crustal weak zone across magnetic reversal epoch and because some undiscovered ancient piece of oceanic crust existed. The crustal structure discrimination still needs to be confirmed by future studies.

OC-027 Does the organisation of services in a geographically diverse region have impact upon delivery of end of life care for patients with upper GI cancer?

IntroductionThe Scottish government “Living and Dying Well” action plan aims to ensure that end of life care needs are recognised in all care settings. This study aims to examine end...

Infinite Dilution Sorption and Thermodynamics of C15–C17 n–alkanes in Perfluorinated Copolymer AF2400

Infinite Dilution Sorption and Thermodynamics of C15–C17 n–alkanes in Perfluorinated Copolymer AF2400

Comparison of the liquid-ordered bilayer phases containing cholesterol or 7-dehydrocholesterol in modeling Smith-Lemli-Opitz syndrome

The phase behavior of egg sphingomyelin (ESM) mixtures with cholesterol or 7-dehydrocholesterol (7-DHC) has been investigated by independent methods: fluorescence microscopy, X-ray diffraction, and electron spin resonance spectroscopy. In giant vesicles, cholesterol-enriched domains appeared as large and clearly delineated domains assigned to a liquid-ordered (Lo) phase. The domains containing 7-DHC were smaller and had more diffuse boundaries. Separation of a gel phase assigned by X-ray examination to pure sphingomyelin domains coexisting with sterol-enriched domains was observed at temperatures less than 38 degrees C in binary mixtures containing 10-mol% sterol. At higher sterol concentrations, the coexistence of liquid-ordered and liquid-disordered phases was evidenced in the temperature range 20 degrees -50 degrees C. Calculated electron density profiles indicated the location of 7-DHC was more loosely defined than cholesterol, which is localized precisely at a particular depth along the bilayer normal. ESR spectra of spin-labeled fatty acid partitioned in the liquid-ordered component showed a similar, high degree of order for both sterols in the center of the bilayer, but it was higher in the coexisting disordered phase for 7-DHC. The differences detected in the models of the lipid membrane matrix are said to initiate the deleterious consequences of the Smith-Lemli-Opitz syndrome.

A biogeochemical study of sediments from the eutrophic Lake Lugano and the oligotrophic Lake Brienz, Switzerland

The biomarker composition and stable isotope (C, O) ratio values of organic matter (OM) and carbonate from sediment cores from the oligotrophic Lake Brienz and the eutrophic Lake Lugano (both in Switzerland) are compared, in order to obtain information about OM sources and transformation processes. Eutrophic conditions at Lake Lugano are reflected in elevated total organic carbon (TOC) content and hydrogen index (HI) values, as well as higher lipid concentrations. Parallel down core trends in δ13C values of TOC and calcite in the Lake Lugano sediments reflect bioproductivity cycles. Variations in δ18O values of calcite are consistent with changes in mean summer temperature over the time interval covered by the core. In contrast, such a correlation does not exist for Lake Brienz and there the stable isotope composition of calcite reflects its allochthonous origin. In the sediments of both lakes, fatty acid (FA) distributions and the composition of n-alkanols and n-alkanes indicate highly variable proportions of autochthonous OM sources (algae, zooplankton, bacteria) and OM from land plants. Enhanced in situ microbial synthesis during sediment deposition in Lake Lugano is suggested by the higher TOC-normalised concentrations of branched chain FAs (C15–C17), hopanoic acids and triterpenoid alcohols (i.e. tetrahymanol, diplopterol). Variations in the concentrations of cholesterol are related to contributions from zooplankton and/or green algae, while sitosterol concentrations reflect the input of vascular plants. Periods of increased input of OM from diatoms are evidenced by high 24-methylcholesta-5,22-dien-3β-ol (either epibrassicasterol or brassicasterol) and/or highly branched isoprenoid (HBI) alkenes concentrations. High relative concentrations of diplopterol in Lake Lugano sediments are consistent with the predominance of cyanobacteria commonly observed in eutrophic lakes. The presence of archeol and hydroxyarcheol in very low concentrations in the Lugano sediments argues for the activity of methanogens and/or anaerobic methanotrophs.Differences in OM degradation processes are reflected in higher chlorin index values in the Brienz sediments but higher saturated vs. unsaturated n-FAs in the core from Lugano. Higher concentrations of branched chain FAs and 16:1ω7 n-FA, as well as enhanced 18:1ω7/18:1ω9 n-FA, are consistent with enhanced bacterial biomass in the Lugano water column or sediments. The preservation of phytol seems to be enhanced in sediments with a high relative contribution of land plant OM. Major factors affecting OM accumulation in the lakes are differences in OM sources (i.e. terrestrial OM vs. autochthonous production), extent of bacterial activity and most likely oxygen availability in the water column.

The structure of n-alkane binary mixtures adsorbed on graphite

The thermodynamics and structure of the surface adsorbed phase in binary C15–C16 and C15–C17 n-alkane mixtures confined in graphite pores have been studied by differential scanning calorimetry and small-angle X-ray scattering. The previously observed selective adsorption of the longer alkane for chain length differences greater than five carbon atoms is verified but reduced for chain length differences less than or equal to two. With a difference in chain length of one carbon atom, Vegard's law is followed for the melting points of the adsorbed mixture and the (0 2) d-spacing is a continuous function of the mole fraction x. With a two-carbon atom difference, samples aged for 1 week have a lamellar structure for which the entities A 1− x B x try to be commensurate with the substrate. The same samples aged for 1 month show a continuous parabolic x-dependence for both the melting points and the d-spacings. An explanation in terms of selective probability of adsorption is proposed based on crystallographic considerations.

Modeling the interaction between FK506 and FKBP12: A mechanism for formation of the calcineurin inhibitory complex

FK506 is a naturally occurring immunosuppressant whose mode of action involves formation of an initial complex with the cytosolic protein FKBP12. The composite surface of this complex then binds to and inhibits the protein phosphatase calcineurin (PP2B). To investigate why FK506 does not inhibit calcineurin directly we have conducted molecular modeling and conformational studies on published structures of FK506 both alone and in complex with FKBP12. From studies of the structure of FK506 in CDCl 3 and Z-Arg32-ascomycin in water (a water soluble analogue of FK506) we suggest that the FK506 molecule can be viewed as consisting of three separate regions. The pipecolate region which extends from C24 to C10 including the pipecolate ring shows strongly conserved conformation in both solvents. The loop region which extends from C25 to C16 shows general conservation of the loop structure and the pyranose region made up of the pyranose ring and C15–C17 which shows highly variable conformation depending on solvent. Comparison of the structure of Z-Arg32-ascomycin in water with structures of FK506 bound to FKBP12 indicate that the conformation of the pipecolate region is conserved during the binding process. The conformation of the loop region was generally conserved but a significant reduction (∼1.7 Å) in the diameter of the loop in the bound structure was observed. The conformation of the pyranose ring and C15–C17 region was found to be significantly altered in the bound structure resulting in displacements of the C13 and C15 methoxyl groups of 2.8 and 3.5 Å, respectively. From computer models and molecular dynamics simulations of interactions between FK506 and FKBP12 we suggest that the conformational changes observed in bound FK506 are induced by the interaction between the 80's loop of FKBP12 and the pyranose ring of FKBP12. These interactions result in the formation of a complex with the both correct shape and surface polarity for interaction with calcineurin.

Volatile Components in Blue Crab (Callinectes sapidus) Meat and Processing By‐Product

ABSTRACTVolatile components in fresh‐picked blue crabmeat and processing byproduct were compared by simultaneous steam distillation‐solvent extraction/gas chromatography/mass spectrometry (SDE/GC/MS). Compounds were identified in crabmeat (771 and by‐product (80) of which 58 were common to both. Some compounds 154) were identified for the first time in crab. Trimethylamine, four alkanes (C15–C17, C19), and indole were highest (> 50 ng/g)) in crabmeat, while trimethylamine, carbon disulfide, dimethyltrisulfide, two alkanes (C15 and C17), geranylacetone, and 1–dodecanol were highest in by‐product. Of compounds from both samples, 23 were higher in by‐product and 7 were higher in the meat. Crab processing by‐product may be a good source for volatile flavor recovery.

Study on Polymorphism of Monoglycerides. IV.

With a total of 10 kinds of synthesized 1-monoglycerides, seven of even-numbered monoglycerides of C10 to C22 (Carbon numbers of fatty acid) and odd-numbered monoglycerides of C15 C17 and C19, examinations were made on the presence of Sub- α2, and their correlation to modification numbers, transition temperature, enthalpy and entropy by difference in length of the molecular chain and even-odd number of carbons. 1) Sub- α2 was observed not only in C18, C20 and C22, but also in C19, but not in those below C17. Comparison of the IR spectrum of Sub- α2 with that of Sub- α1 showed that they are quite similar with the exception of a slight difference in the OH absorption band. Transition from Sub- α2 to Sub- α1 is reversible. 2) Transition temperature (below 310 K, 37°C) of monoglycerides with a short chain of below C15 showed a difference from the values reported in literature when in metastable state (α, Sub α1). Regarding its correlation to the number of carbons, transition temperature of α→ fusion and α → fusion increased β → regulary with increase in the number of carbons, and there was no alternation between even and odd number of carbons. However, such alternation was seen in the transition of Sub- α1 to α and of Sub- α2 to to Sub- α1, and this phenomenon was entirely reverse of that in triglycerides.3) With respect to the correlation of enthalpy and entropy to the number of carbons, enthalpy and entropy of α → fusion and Sub- α1→α of manoglycerides with above C17 chain showed the same tendency as the transition temperature. Alternation appeared in the case of β→ fusion, differing from the transition temperature. This may be due to the difference in the optically active L and DL compounds of monoglycerides. In the transition of Sub-α to α in monoglycerides of less than C16, transition enthalpy increased in inverse proportion to the decrease in the number of carbons. This may be due to the occurrence of a competitive action between the fatty acid group and glycerol group at the time of transition, resulting in the increasing action of the glycerol group with shortening of the molecular chain and in a metastable state. The enthalpy and entropy per methylene group were R/2 and Rln 3, respectively, agreeing well with theoretical values.

Study on Polymorphism of Monoglyceride. I.

With a total of 10 kinds of synthesized 1-monoglycerides, seven of even-numbered monoglycerides of C10 to C22 (Carbon numbers of fatty acid) and odd-numbered monoglycerides of C15 C17 and C19, examinations were made on the presence of Sub- α2, and their correlation to modification numbers, transition temperature, enthalpy and entropy by difference in length of the molecular chain and even-odd number of carbons. 1) Sub- α2 was observed not only in C18, C20 and C22, but also in C19, but not in those below C17. Comparison of the IR spectrum of Sub- α2 with that of Sub- α1 showed that they are quite similar with the exception of a slight difference in the OH absorption band. Transition from Sub- α2 to Sub- α1 is reversible. 2) Transition temperature (below 310 K, 37°C) of monoglycerides with a short chain of below C15 showed a difference from the values reported in literature when in metastable state (α, Sub α1). Regarding its correlation to the number of carbons, transition temperature of α→ fusion and α → fusion increased β → regulary with increase in the number of carbons, and there was no alternation between even and odd number of carbons. However, such alternation was seen in the transition of Sub- α1 to α and of Sub- α2 to to Sub- α1, and this phenomenon was entirely reverse of that in triglycerides.3) With respect to the correlation of enthalpy and entropy to the number of carbons, enthalpy and entropy of α → fusion and Sub- α1→α of manoglycerides with above C17 chain showed the same tendency as the transition temperature. Alternation appeared in the case of β→ fusion, differing from the transition temperature. This may be due to the difference in the optically active L and DL compounds of monoglycerides. In the transition of Sub-α to α in monoglycerides of less than C16, transition enthalpy increased in inverse proportion to the decrease in the number of carbons. This may be due to the occurrence of a competitive action between the fatty acid group and glycerol group at the time of transition, resulting in the increasing action of the glycerol group with shortening of the molecular chain and in a metastable state. The enthalpy and entropy per methylene group were R/2 and Rln 3, respectively, agreeing well with theoretical values.