bluuebunny/crossref_metadata_2025 huggingface dataset:
Amino acid pairing at the N‐ and C‐termini of helical segments in proteins
Authors: Fonseca Nuno A. , Camacho Rui , Magalhães A. L.
Published: July 2007

A systematic survey was carried out in an unbiased sample of 815 protein chains with a maximum of 20% homology selected from the Protein Data Bank, whose structures were solved at a resolution higher than 1.6 Å and with a R‐factor lower than 25%. A set of 5556 subsequences with α‐helix or 310‐helix motifs was extracted from the protein chains considered. Global and local propensities were then calculated for all possible amino acid pairs of the type (i, i + 1), (i, i + 2), (i, i + 3), and (i, i + 4), starting at the relevant helical positions N1, N2, N3, C3, C2, C1, and N‐int (interior positions), and also at the first nonhelical positions in both termini of the helices, namely, N‐cap and C‐cap. The statistical analysis of the propensity values has shown that pairing is significantly dependent on the type of the amino acids and on the position of the pair. A few sequences of three and four amino acids were selected and their high prevalence in helices is outlined in this work. The Glu‐Lys‐Tyr‐Pro sequence shows a peculiar distribution in proteins, which may suggest a relevant structural role in α‐helices when Pro is located at the C‐cap position. A bioinformatics tool was developed, which updates automatically and periodically the results and makes them available in a web site. Proteins 2008. © 2007 Wiley‐Liss, Inc.
A potential molecular switch in an α‐helical coiled coil
Authors: Laughton Charles A. , Luisi Ben F. , Pratap J. Venkatesh , Calladine Chris R.
Published: July 2007

The yeast DNA‐binding protein GCN4 forms a homo‐dimer through a self‐complementary coiled‐coil interface. In this article, we describe how such coiled‐coils might be bistable and, through Molecular Dynamics computations on the GCN4 coiled coil, we show that the coiled coil can indeed switch between the two states by a pathway in which there is a progressive “flipping” of consecutive steps along the interface. We discuss the general implications of potentially bistable coiled‐coil interfaces for allosteric signal‐transmission mechanisms along homo‐dimeric coiled coils and for the packing of helices in globular proteins. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Identification of fungal oxaloacetate hydrolyase within the isocitrate lyase/PEP mutase enzyme superfamily using a sequence marker‐based method
Authors: Joosten Henk‐Jan , Han Ying , Niu Weiling , Vervoort Jacques , Dunaway‐Mariano Debra , Schaap Peter J.
Published: July 2007

Aspergillus niger produces oxalic acid through the hydrolysis of oxaloacetate, catalyzed by the cytoplasmic enzyme oxaloacetate acetylhydrolase (OAH). The A. niger genome encodes four additional open reading frames with strong sequence similarity to OAH yet only the oahA gene encodes OAH activity. OAH and OAH‐like proteins form subclass of the isocitrate lyase/PEP mutase enzyme superfamily, which is ubiquitous present filamentous fungi. Analysis of function‐specific residues using a superfamily‐based approach revealed an active site serine as a possible sequence marker for OAH activity. We propose that presence of this serine in family members correlates with presence of OAH activity whereas its absence correlates with absence of OAH. This hypothesis was tested by carrying out a serine mutagenesis study with the OAH from the fungal oxalic acid producer Botrytis cinerea and the OAH active plant petal death protein as test systems. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Identification and structural characterization of heme binding in a novel dye‐decolorizing peroxidase, TyrA
Authors: Zubieta Chloe , Joseph Rosanne , Sri Krishna S. , McMullan Daniel , Kapoor Mili , Axelrod Herbert L. , Miller Mitchell D. , Abdubek Polat , Acosta Claire , Astakhova Tamara , Carlton Dennis , Chiu Hsiu‐Ju , Clayton Thomas , Deller Marc C. , Duan Lian , Elias Ylva , Elsliger Marc‐André , Feuerhelm Julie , Grzechnik Slawomir K. , Hale Joanna , Han Gye Won , Jaroszewski Lukasz , Jin Kevin K. , Klock Heath E. , Knuth Mark W. , Kozbial Piotr , Kumar Abhinav , Marciano David , Morse Andrew T. , Murphy Kevin D. , Nigoghossian Edward , Okach Linda , Oommachen Silvya , Reyes Ron , Rife Christopher L. , Schimmel Paul , Trout Christina V. , van den Bedem Henry , Weekes Dana , White Aprilfawn , Xu Qingping , Hodgson Keith O. , Wooley John , Deacon Ashley M. , Godzik Adam , Lesley Scott A. , Wilson Ian A.
Published: July 2007

TyrA is a member of the dye‐decolorizing peroxidase (DyP) family, a new family of heme‐dependent peroxidase recently identified in fungi and bacteria. Here, we report the crystal structure of TyrA in complex with iron protoporphyrin (IX) at 2.3 Å. TyrA is a dimer, with each monomer exhibiting a two‐domain, α/β ferredoxin‐like fold. Both domains contribute to the heme‐binding site. Co‐crystallization in the presence of an excess of iron protoporphyrin (IX) chloride allowed for the unambiguous location of the active site and the specific residues involved in heme binding. The structure reveals a Fe‐His‐Asp triad essential for heme positioning, as well as a novel conformation of one of the heme propionate moieties compared to plant peroxidases. Structural comparison to the canonical DyP family member, DyP from Thanatephorus cucumeris (Dec 1), demonstrates conservation of this novel heme conformation, as well as residues important for heme binding. Structural comparisons with representative members from all classes of the plant, bacterial, and fungal peroxidase superfamily demonstrate that TyrA, and by extension the DyP family, adopts a fold different from all other structurally characterized heme peroxidases. We propose that a new superfamily be added to the peroxidase classification scheme to encompass the DyP family of heme peroxidases. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Structural characterization of native high‐methoxylated pectin using nuclear magnetic resonance spectroscopy and ultraviolet matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Comparative use of 2,5‐dihydroxybenzoic acid and nor‐harmane as UV‐MALDI matrices
Authors: Monge María Eugenia , Negri R. Martín , Kolender Adriana A. , Erra‐Balsells Rosa
Published: July 2007

The successful analysis by ultraviolet matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (UV‐MALDI‐TOF MS) of native and hydrolyzed high‐methoxylated pectin samples is described. In order to find the optimal conditions for UV‐MALDI‐TOF MS analysis several experimental variables were studied such as: different UV‐MALDI matrices (nor‐harmane, 2,5‐dihydroxybenzoic acid), sample preparation methods (mixture, sandwich), inorganic salt addition (doping salts, NaCl, KCl, NH4Cl), ion mode (positive, negative), linear and reflectron mode, etc. nor‐Harmane has never been used as a UV‐MALDI matrix for the analysis of pectins but its use avoids pre‐treatment of the sample, such as an enzymatic digestion or an acid hydrolysis, and there is no need to add salts, making the analysis easier and faster. This study suggested an alternative way of analyzing native high‐methoxylated pectins, with UV‐MALDI‐TOF MS, by using nor‐harmane as the matrix in negative ion mode. The analysis by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy of the native and hydrolyzed pectin is also briefly described. Copyright © 2007 John Wiley & Sons, Ltd.
A liquid chromatography/atmospheric pressure ionization tandem mass spectrometry quantitation method for nevirapine and its two oxidative metabolites, 2‐hydroxynevirapine and nevirapine 4‐carboxylic acid, and pharmacokinetics in baboons
Authors: Liu Zhongfa , Fan‐Havard Patty , Xie Zhiliang , Ren Chen , Chan Kenneth K.
Published: July 2007

A rapid highly sensitive and specific electrospray ionization (ESI) liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for quantification of nevirapine (NVP) and its two metabolites, 2‐hydroxynevirapine (2‐OHNVP) and nevirapine 4‐carboxylic acid (4‐CANVP), in baboon serum was developed and validated. Nevirapine, 2‐OHNVP, 4‐CANVP, and the internal standard, hesperetin, were extracted from baboon serum with ethyl acetate. Components in the extract were separated on a 50 × 2.1 mm Aquasil C185 µm stainless steel column by isocratic elution with 40% acetonitrile/0.1% formic acid at a flow rate of 0.2 mL/min. The liquid flow was passed through a pre‐source splitter and 5% of the eluant was introduced into the atmospheric pressure ionization (API) source. The components were analyzed in the multiple‐reaction monitoring (MRM) mode as the precursor/product ion pair ofm/z267.2/226.2 for NVP, 283.0/161.2 for 2‐OHNVP, 297.2/279.2 for 4‐CANVP, and 303.2/177.2 for hesperetin. Linear calibration curves were obtained in the range of 1–1000 ng/mL for NVP and 2‐OHNVP and 5–1000 ng/mL for 4‐CANVP, using 0.2 mL baboon serum, respectively. The within‐day and between‐day precisions were <10% for NVP and 2‐OHNVP, and <11.5% for 4‐CANVP. Due to the similar structures and fragmentation patterns of 2‐OHNVP and 3‐OHNVP, it is not expected that the LC/MS/MS can differentiate 2‐OHNVP and 3‐OHNVP and they were assayed as a composite. The method was applied to a single‐dose escalation study of NVP in non‐pregnant baboons (Papio anubis) to characterize the pharmacokinetics of NVP, 2‐OHNVP plus 3‐OHNVP, and 4‐CANVP, and to determine the appropriate dose necessary to achieve comparable peak serum concentration of NVP as reported in healthy human adults. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of progestins on serum hormones, semen production, and agonistic behavior in the gerenuk (Litocranius walleri walleri)
Authors: Penfold Linda M. , Munson Linda , Plotka Ed , Citino Scott B.
Published: July 2007

The use of progestins to suppress endogenous testosterone production to reduce agonistic behavior and prevent semen production was studied in gerenuk. Five male gerenuk (20 months to 3 years of age), housed as a bachelor group, were treated with 3 monthly injections of medroxyprogesterone acetate (MPA; 2.5–20 mg/kg), followed by a melengestrol acetate implant (MGA; 0.3 g/kg) for 2 months. Blood samples collected monthly were assayed for serum testosterone and cortisol using enzyme‐linked immunoassays. Quantitative behavioral data were collected for 30 min 3/week starting 1 month before treatment. Body weight, testes volume, and semen traits were measured before treatment, after MPA treatment, and after MGA treatment. Results showed lower (P<0.05) mean serum testosterone concentrations after MPA (4.34 pg/ml) and MGA (5.02 pg/ml) treatment compared to pre‐treatment values (65.9 pg/ml) in four of five gerenuk. The remaining sub‐adult gerenuk had low testosterone initially (4.9 pg/ml) that did not decrease further with treatment (1.4 and 7.8 pg/ml for MPA and MGA, respectively). Mean serum cortisol concentrations decreased markedly after treatment with MPA (6.0±3.7 ng/ml) and MGA (0.8±0.3 ng/ml). Cortisol concentrations were regained rapidly post‐treatment (42.8±4.8 ng/ml) and were not significantly different from the pre‐treatment value (60.6±12.6 ng/ml; P>0.05). The mean incidence of combined aggressive/dominant behaviors (horning, sparring, supplanting, threat) was not different before and after treatment. Body weight, total numbers of spermatozoa produced per ejaculate, percent motility, and percent normal spermatozoa declined maximally 8 months after treatment. Mean testes volume decreased (P<0.05) after MGA treatment (10.53 cm3vs. 11.96 cm3 pre‐treatment). Elevated hepatic enzymes and bile acids were seen in three of five animals after progestin treatment and anorexia was noted in two males after MGA implant removal, however two of three males had elevated liver enzymes before progestin treatment began. Results show that reducing serum testosterone concentration does not seem to modify agonistic behavior in bachelor gerenuk groups. Zoo Biol 26:245–257, 2007. © 2007 Wiley‐Liss, Inc.
Solubility of tristearin and hydrogenated cottonseed oil in certain aceto‐ and butyroglycerides
Authors: Ward T. L. , Gros Audrey T. , Feuge R. O.
Published: July 2007

Tristearin, triolein, 1,2‐diaceto‐3‐olein, an acetoolein product, and 1,2‐dibutyro‐3‐olein were prepared. Also a commercial, refined, and bleached cottonseed oil was hydrogenated to obtain products having iodine values of 29.3 and 1.1. Solubility measurements were made for the mixtures tristearin‐triolein, tristearin‐1,2‐diaceto‐3‐olein, tristearin‐1,2‐dibutyro‐3‐olein, and for hydrogenated cottonseed oils in the aceto‐olein product and cottonseed oil.

In mixtures containing from 0.18% to approximately 30% of tristearin the solubility on a weight basis was unaffected by the nature of the oil. On a mole fraction basis the tristearin was most soluble in the triolein and least soluble in the 1,2‐diaceto‐3‐olein. Hydrogenated cottonseed oil appeared to be about equally soluble, on a weight basis, in the aceto‐olein product and cottonseed oil.
An instrumental method for measuring the degree of reversion and rancidity of edible oils
Authors: Chang S. S. , Kummerow F. A.
Published: July 2007

The amount of volatile carbonyl compounds diffused from 100 g. of an oil into a stream of nitrogen bubbled through the oil under specified conditions was determined by converting the carbonyl compounds into their 2,4‐dinitrophenylhydrazones and then measuring the absorption of the wine‐red color of the quinoidal ions at 480 mμ. From the absorbance thus obtained, a carbonyl index was calculated and assigned to the oil.

The carbonyl indices of a number of edible oils, such as soybean, cottonseed, and hydrogenated vegetable, were found to correlate with the degree of reversion and rancidity of the oils as determined by organoleptic means. The reproducibility of the carbonyl index determination was 3%. This accuracy corresponded to approximately ±0.1 point in an organoleptic testing panel in which 1 point represented a very unacceptable oil and 10 points a very good oil. The carbonyl index method may also be used as a means of evaluating the flavor stability of edible oils. The carbonyl index gave a good indication of the flavor stability after aging at 60°C. for the less stable and 100°C. for the more stable oils and fats.
Development of buckeye continuous moisture meter for oil‐bearing materials
Authors: Maskey D. F. , Ledbetter D. M. , Craig H. L.
Published: July 2007

A continuous recording moisture meter was needed in processing oil‐bearing seed materials. Two successful meters, similar in principle but different in design, have been developed.

Theoretical considerations involved in designing such a meter are presented, with circuit diagrams and descriptions of test cells. The work with Arthur D. Little Inc. is reviewed, also the independent development by the Buckeye Cotton Oil Company.

Continuous moisture meters are valuable aids in plant operation greatly improving moisture control in soybean meal and saving operator time. Their value is in the plant; they do not have the accuracy of a laboratory instrument.

The continuous moisture meters described are presented to the industry for their demonstrated value and superiority over batch‐type meters.
The chemical utilization of fats and oils. III. Ester‐amides of certain aminoalcohols as plasticizers
Authors: Silverstein R. M. , Mosher C. W. , Richards L. M.
Published: July 2007

A number of ester‐amides and diester‐amides of aminoalcohols were prepared and evaluated as plasticizers. Screening tests established the necessity of a secondary amine group in the aminoalcohol to impart the desired degree of compatibility with vinyl resins.

Optimum plasticizer properties were attained with the C8 and C10 diester‐amides of diethanolamine. The mixture of caprylic and capric acids as obtained from coconut oil was convenient and economical.
Preparation of fat emulsions for intravenous alimentation
Authors: Geyer Robert P. , Olsen F. Russell , Andrus Stephen B. , Waddell William R. , Stare Fredrick J.
Published: July 2007

Descriptions are given of the high pressure homogenization equipment used and of the actual procedure followed in the preparation of fat emulsions suitable for intravenous nutrition. Such emulsions contain 10–15% oil (w/v) dispersed in particles less than one micron in diameter. They are made under nitrogen and subsequently autoclaved to ensure sterility.

Procedures are also given for screening each batch of emulsion by means of tests performed on rats, dogs, and rabbits. Emulsions of the type described have found extensive application in the clinic with a low incidence of unfavorable reactions.
Synthetic detergents from animal fats. V. Esters from alpha‐sulfonated fatty acids and sodium isethionate
Authors: Weil J. K. , Bistline R. G. , Stirton A. J.
Published: July 2007

Disodium 2–sulfoethyl α‐sulfopalmitate, disodium 2‐sulfoethyl α‐sulfostearate, and disodium 2‐sulfoethyl α‐sulfobehenate were prepared by esterification of the corresponding α‐sulfonated acid with sodium isethionate. Disodium 1‐methyl‐2‐sulfoethyl α‐sulfostearate was made from sodium 2‐hydroxypropanesulfonate. The esters were found to be readily soluble surface‐active agents and detergents, very responsive to building with inorganic phosphates and sulfates.

Compared to sodium 2‐sulfoethyl oleate the esters were readily prepared without the necessity of making the acid chloride; they were considerably more resistant to acid or alkaline hydrolysis; they were about equal in their excellent lime soap dispersing power, but inferior in foaming properties, producing a less permanent foam.

The esters were easily soluble because of the presence of two sulfo groups and were improved detergents in the presence of inorganic builders. Mixtures of the palmitic and stearic acid derivatives, such as might be obtained from the saturated acids of tallow, containing a total of 20% active ingredient, were effective detergents in hard water.

Disodium 1‐methyl‐2‐sulfoethyl α‐sulfostearate, an ester of a secondary alcohol, was even more resistant to alkaline hydrolysis than the esters from sodium isethionate.
Solvent hydrogenation of cottonseed oil
Authors: Albright Lyle F. , Wei Chin‐Hsuan , Woods John M.
Published: July 2007

Refined and bleached cottonseed oil was dissolved in a solvent (hexane, isopropyl alcohol, or di‐isopropyl ether) and was then hydrogenated in a dead‐end hydrogenator. Hydrogenation runs were conducted at temperatures from 115 to 145°C., at hydrogen partial pressures from 44 to 74 p.s.i.a., with catalyst concentrations varying from 0.05 to 0.40% nickel, and at high rates of agitation to climinate mass‐transfer resistances. A series of hydrogenation runs was also made in which no solvent was used.

The rates of hydrogenation for the various series of runs were in the same order of magnitude but decreased in the following order: nonsolvent, hexane, isopropyl alcohol, and di‐isopropyl other runs. Selectivity and isomerization were low in all cases and essentially identical for solvent and nonsolvent runs.

The rate of hydrogenation increased in all cases with higher catalyst concentrations. For the isopropanol runs, the reaction rate was maximum as a function of temperature at about 135°C. In the case of the other solvents, the rate of hydrogenation increased with increased temperature in the range from 115 to 145°C., but the rate increases of the solvent runs were less than those of the nonsolvent runs.
Outlook for the global economy
Authors: Grimm Hans‐Ulrich
Published: July 2007

The end of the 1970s also brought to a close a growth phase of the world economy which had lasted more than 20 years and been interrupted only by relatively mild reverses. Although, after a recession of somewhat longer than 2 years, the preconditions have now improved for a return to the path of economic recovery, at least in most industrial countries, there is no cause for an excessive measure of optimism. Due to their high mountains of debt to other nations, a majority of the large newly emerging industrial countries (the so‐called threshold nations) and of the developing countries will be forced to assign first priority to an improvement in their balances of payments over the next few years and will therefore largely fail to act as additional customers for foreign goods. In many industrial countries—again as a result of voluminous indebted‐ness—narrow limits have been placed on an expansive economic policy course. Besides, the markets served by these nations exhibit a high degree of saturation. In such an environment, the best growth prospects are held by those industries which succeed in creating new requirements and demands on their traditional markets. This is one of the principal reasons why innovation will play an even more important part in the future than it has already played in the past. It can be fairly estimated that the consumer goods industries and the service sector will develop more favorably within the span of the next 12–18 months than the capital goods industries. From a geographic viewpoint it can be assumed on the basis of the existing evidence that during this period economic performance will be stronger in the USA and Japan than in Western Europe. Prospects for an economic comeback in Europe are best in Great Britain, the Federal Republic of Germany and in Italy.
Challenges to a mature industry: Marketing and economics of oleochemicals in Western Europe
Authors: Richtler H. J. , Knaut J.
Published: July 2007

Basic oleochemicals are produced by splitting and further reactions of oils and fats: fatty acids, glycerine, fatty acid methyl esters, fatty alcohols and amines. The last two are included in the list of oleochemical raw materials, primarily because of their importance in the preparations of further derivatives. The wide range of derivatives of oleochemical raw materials such as fatty alcohol ethoxylates, fatty alcohol sulfates, fatty alcohol ether sulfates, quaternary ammonium compounds and soaps are summarized. Oleochemicals such as fatty alcohols and glycerine from oils and fats have equivalents on the basis of petrochemicals. Using the customary terminology, petrochemical products are referred to as “synthetics.” The are included in the present discussion because in the application of oleochemical raw materials the origin of the material is often less important than the structure. Oleochemistry can be regarded as a mature branch of chemistry, with many applications for its products, but with few completely new fields. The challenge and the opportunities for oleochemistry today lie in the changing economic and ecological conditions. Availability and price development of oils and fats are discussed with particular reference to European conditions, for these are the prerequisites if oleochemicals are to be competitive and are to improve their chances in the marketplace. The importance and development of the oleochemical raw material fatty acids, fatty acid methyl esters, glycerine, fatty alcohols and amines are considered on the basis of historical data. In considering future developments of oleochemicals, the capacity, demand and the possible influence of petrochemistry or crude oil is discussed. The highly developed oleochemical raw materials industry is a flexible supplier of medium‐to long‐chain fatty alkyl groups. These facts, together with the well organized supply lines for raw materials and the considerable potential of these renewable raw materials, could provide the necessary conditions for the oleochemical raw materials industry to fulfil its future tasks on a larger scale. This could arise, for example, due to the partial substitution of petrochemical surfactants, if this should become necessary as a result of developments in the price and availability of crude oil, or on grounds of ecological factors.
Challenges to a mature industry: Marketing and economics of oleochemicals in the United States
Authors: Leonard E. Charles , Kapald S L
Published: July 2007

Fatty acids, accounting for more than half of oleochemicals discussed, grew at an annual rate of ca. 3% during the 1970s, with no growth since 1979. As competition intensified, the number of companies in the industry declined or owenrship changed. Challenges are covered under five major headings—markets, raw materials, competition, research and profitability. Oleochemical markets are extremely diverse but usually involve surface modification. Fatty acid disposition and real consumer personal income correlate closely. Growth of consumer income in the 1980s will be the most important factor in determining growth of fatty chemicals. Fatty chemicals compete with petroleum‐derived products; and, therefore, price relationship of natural fats versus petroleum will affect market share. Tallow and other natural fats and oils are approximately the same price as 15 years ago, whereas ethylene has about doubled. Interchangeability of natural fats tends to moderate price fluctuations. Competition remains intense with market shares divided among many companies. Neither imports nor exports have played a significant role in the US fatty chemical industry. There are large exports of fatty acid derivatives, particularly to South America. Research will concentrate on energy reduction as oleochemical production is highly energy‐intensive. Enzymatic splitting is a potential commercial process for this purpose. Improved hydrogenation catalysts and development of new specialty oilseeds are additional research objectives. Success of researchers will probably play the biggest role of all in future marketing and economics of fatty chemical companies. The belief is that the fatty chemical industry has had difficulty in consistently maintaining acceptable levels of profitability. To avoid extinction and achieve reasonable rates of return, business strategies must (a) identify, create and exploit growth segments; (b) emphasize product quality and innovative product improvement; and (c) systematically improve production and distribution efficiencies.
Marketing and economics of oleochemicals to the plastics industry
Authors: Reck Richard A.
Published: July 2007

The number of oleochemicals used in the plastics industry are many and varied. Usually the chemicals sold are designed for a specific application that depends on the end use and the economics of production. The percentage of oleochemicals that end up in the finished product is small, usually 0.1–1%, but it is there for a very important physical specification that the chemical imparts to the finished resin. The chemicals and applications are discussed by the structure of the additive and the property it imparts to the finished resin. The marketing of oleochemical to the plastics industry usually requires considerable application and process research to develop specialized molecules that impart the desired properties to the finished resin. Market size and economics numbers refer only to the US markets.
Enzymatic fat hydrolysis and synthesis
Authors: Linfield Warner M. , Barauskas Robert A. , Sivieri Lorraine , Serota Samuel , Stevenson Robert W.
Published: July 2007

The hydrolysis of tallow, coconut oil and olive oil, by lipase fromCandida rugosa, was studied. The reaction approximates a firstorder kinetics model. Its rate is unaffected by temperature in the range of 26–46 C. Olive oil is more rapidly hydrolyzed compared to tallow and coconut oil. Hydrolysis is adversely affected by hydrocarbon solvents and a nonionic surfactant. Since amounts of fatty acids produced are almost directly proportional to the logarithms of reaction time and enzyme concentration, this relationship provides a simple means of determining these parameters for a desired extent of hydrolysis. All three substrates can be hydrolyzed, almost quantitatively, within 72 hr. Lipase fromAspergillus niger performs similarly. The lipase fromRhizopus arrhizus gives a slow hydrolysis rate because of its specificity for the acyl groups attached to the α‐hydroxyl groups of glycerol. Esterification of glycerol with fatty acid was studied with the lipase fromC. rugosa andA. niger. All expected five glycerides are formed at an early stage of the reaction. Removal of water and use of excess fatty acid reverse the reaction towards esterification. However, esterification beyond a 70% triglyceride content is slow.
Separation of saturated/unsaturated fatty acids
Authors: Haraldsson G.
Published: July 2007

Fatty acid mixtures can be separated into one fraction rich in saturated fatty acids and the other rich in unsaturated acids. Since saturated fatty acids have a higher melting point than unsaturated, liquid mixture to be fractionated is cooled to a temperature at which the larger part of the saturated acids crystallize, while the greater part of unsaturated acids remain in liquid form. Different industrial methods to separate the two phases are described. The oldest and simplest method is slowly to cool and crystallize the mixture in shallow pans to form cakes which then are pressed in presses of different design. By applying high pressure, the liquid olein is thus squeezed out from the cake, leaving the stearin fraction behind. A new process to separate the phases is to mix an aqueous solution, containing a wetting agent, with the crystallized fatty acid mixture. The stearin crystals are thus wetted and transferred into the aqueous phase, which then can be separated from the olein phase in a centrifuge. The stearin/aqueous suspension is heated to melt the stearin, which can then be separated in a second centrifuge. Other methods to improve phase separation use organic solvents, among which are methanol, acetone, methyl formate and propane. In the solvent fraction process, the miscella has to be cooled to a lower temperature than in the aforementioned methods, due to the solubility effect of the solvents. The solvents are removed by distillation from the fraction. Typical operation results with different types of raw materials are given. The advantages and disadvantages of the different methods are discussed.
Practical implications of fatty acid topography modification by unsaturation
Authors: Duncan Don P.
Published: July 2007

Unsaturated fatty acids are markedly different from their saturated counterparts in a number of areas that relate only to the physical properties given them by their topography. In systems where free single bond rotation is restricted, such as monolayers or biomembranes, the effectiveness of chain packing and the fluidity of the fatty chain region is critical and here may best be studied. Topography plays a role in many chemical reactions in terms of reaction rate and product stereochemistry, but is less critical here. Topography hindrances to reaction rate often may be overcome by raising the reaction temperature. When stereochemistry is important, however, the topography of the reactants must be considered. In tightly packed crystalline bulk or condensed monolayer states, the conformation assumed by the chain is its most stable one, excluding polymorphism. This conformation usually will approximate the one of greatest stability for the free molecule in a nonrestricting environment. However, because differences in energy between rotational conformers is generally small, departures from the preferred conformation will be abundant in the absence of constraints imposed by neighboring molecules. Therefore, in the absence of a restricting environment, topographical differences will be minimized. The counterpoint to this is that a large percentage of the fatty acids in use are in such restricting environments in biomembranes, soaps, wetting and foaming agents, fabric afteners, etc., or are purified through a process maiing use of differences in chain packing efficiency, crystallization, where their topography is the primary source of their utility.
Telomer Acids: Monocarboxylic acids with long‐chain branching; Their derivatives, properties and potential uses in lubricants
Authors: Van Brederode H. , de Klein W. J.
Published: July 2007

Telomer acids are synthesized by addition of acetic anhydride to α‐olefins using managenese (III) acetate as a free radical initiator. The telomerization mechanism comprises initiation, propagation and termination steps. The reaction product consists of a mixture of acids having [xn+2] carbon atoms (n: number of carbon atoms of α‐olefin: x:1, 2, 3, 4, …). The “first telomer” (x=1) is a linear fatty acid. Under appropriate conditions, mainly telomer acid (x:2, 3, 4, …) are obtained, being α‐ and γ‐branched monocarboxylic acids, characterized by long‐chain branches. Telomer acids derived from α‐olefins up to n=14 are liquids at room temperature, despite the high molecular weight. Esters of telomer acids show interesting properties in lubricant applications: low pour point, high viscosity index, low viscosity as a function of molecular weight, good thermo‐oxidative stability and a remarkably low elastomer swell. In amino amide derivatives, the telomer acid structure gives low viscosity properties, as is, for instance, found in significant viscosity reductions by using telomer acid as coreactant in polyisobutenyl succinic anhydride—tetraethylene pentamine condensation products. Dispersancy properties of these products are retained. Telomer acid metal salts exhibit quite different solubility characteristics and rheological properties than do fatty acid salts. Calcium salts of telomer acids are readily soluble in mineral oil: the rheology of these low viscosity solutions exhibits Newtonian behavior. Solvent‐free magnesium salts which are liquid can be obtained. Neutral and overbased calcium salts show pour point depressing activity in paraffinic oils. For overbased calcium salts, decrease of coefficient of friction with increasing temperature has been observed.
Oleochemicals: Feedstock or auxiliary
Authors: Heidrich J. F.
Published: July 2007

Today's oleochemicals are substances which are used not mainly because of their sophisticated chemical structures or their chemical reactivity, but rather because of their adaptability as auxiliaries in a great variety of formulated products. This has determined their success in the marketplace. The conversion to long‐chain building blocks for polymers is one possibility to move oleochemicals into a larger scale position as feedstocks. In the near future, this objective cannot be reached because two factors limit their economical chemical derivation; namely, the missing technologies to separate chemical individuals with one or two double bonds in the alkyl chain from the natural mixtures, and to cleave double bonds in a controlled way, without forming larger quantities of byproducts. In any case, before oleochemicals (e.g., fatty acid methyl esters) are used as substitutes for gasoil, as is already tried in certain countries, the chemical potential of oleochemicals should be exploited. That means: “Use it‐don't burn it!” Today's chemical processes and uses for oleochemicals are discussed.
Development of new crops for industrial raw materials
Authors: Princen L. H. , Rothfus J. A.
Published: July 2007

Commercial fats and oils are still used extensively in chemical manufacturing processes, but their fatty acid compositions are limited in variety. An extensive screening program for potential new oilseed crops has led to the discovery of many good sources of new lipid classes and fatty acids. Among them are long‐chain acids (Crambe, Limnanthes, Lunaria), medium‐chain acids (Cuphea, Umbelliferae, Lauraceae), hydroxy acids (Lesquerella), epoxy acids (Vernonia, Stokesia), acids with special unsaturation (conjugated; acetylenic; Δ3, Δ5, Δ6, Δ17 monoenes) and liquid wax esters (Simmondsia). Many of these plant species have received further attention in terms of germplasm collection and evaluation; breeding and agronomic studies; and processing and utilization research on oil and byproduct meal. Some have been developed sufficiently for early commercialization. Recent history has shown this last step to be the most difficult. No satisfactory mechanism has been devised as yet to simplify the process of transferring research information on a developed new crop to reach the ultimate goal of sustained, large‐scale commerical production. Close cooperation between governments and private sector institutions, with some financial support, may be required for the first few years to achieve successful commercialization.
Current pollution control practices in the united states
Authors: Boyer Michael J.
Published: July 2007

An overview of pollution control practices in the United States is presented here, with particular emphasis on those factors which motivate and direct current practices. A more in‐depth discussion is provided of certain areas, particularly those items which might be unique to the USA. More emphasis has been placed on wastewater‐related issues. The largest dollar expenditures and technical efforts have probably gone to solving these problems in the oleochemical field. Some example projects are presented to demonstrate the significant points.
Water protection in Europe
Authors: Malle Karl‐Geert
Published: July 2007

In addition to national regulations there are supranational as well as international conventions for protection of Europcan waters. Supranational directives have been passed by the European Community concerning for instance, the quality of bathing water and of fish as well as shellfish waters, on the quality of drinking water and surface waters for production of drinking water. The directive on “pollution caused by certain dangerous substances discharged into the aquatic environment” is of special importance. A number of international conventions with special purviews correspond to this directive. The purpose of all the regulations is to control pollution caused by dangerous substances. With regard to substances of “list 1”, pollution is to be eliminated by fixing emission standards for all discharges., To reduce pollution by substances of “list II”, member states shall lay down emission standards which are based on standardized quality objectives. These standards shall be harmonized by the Europcan Commission. The conventions contain only lists of families and groups of substances, among which certain individual substances first have to be, selected. Meanwhile, 46 substances are under examination: for 83 more substances, discussion is proposed. This procedure is rather complicated. Technological aspects such as amounts, production processes, use and treatment technology are taken into account as well as ecological properties like toxicology, persistence and bioaccumulation. Examination also includes the economic problems involved. The proposals for emissions standards and quality objectives thus resulting have to pass through the normal legislative procedure before becoming legally binding on the respective states. The first implementing directive is limiting the mercury discharges from the chlor‐alkali electrolysis (amalgam process). Furthermore, there are proposals for a drins as well as a cadmium directive. The first substance of, list II under examination is chromium with its compounds.
Large‐scale production and application of highly concentrated ozone
Authors: Klein Hans‐Peter
Published: July 2007

With the new, very efficient generating plants, ozone can be produced in high concentrations, at low cost and with high reliability. This versatile reagent is therefore destined, in the near future, to play a more important role in the oleochemical industry than today, since it can help to solve different problems in the synthesis of chemicals as well as in the treatment of waste.
Properties and uses of some unsaturated fatty alcohols and their derivatives
Authors: Egan Richard R. , Earl Gary W. , Ackerman Jeannene
Published: July 2007

A number of unsaturated fatty alcohols are known, but only those of the C16 and C18 chain lengths are of much importance. In particular, oleyl alcohol., 9,10‐octadecenol‐1, is by far the most important. A variety of grades of oleyl alcohols is produced and used in the USA ranging from high purity material having iodine values (IV) of 90–95 to those having IV of 45–55, with the other components being primarily cetyl (hexadecanol‐1) and stearyl (octadecanol‐1) alcohols. This paper takes a brief look at the various grades of unsaturated alcohols used in the USA, methods of preparation, and the change in physical and chemical properties as the octadecanol‐1 content and IV decline. Uses of these alcohols industrially and in cosmetic and pharmaceutical preparations are also discussed. Unsaturated alcohols are useful chemical intermediates since they have two reactive sites, the hydroxyl group and the carbon‐carbon double bond. Particular attention is paid to the properties, uses and potential uses of some of their sulfates, ether sulfates, ethylene oxide adducts and ethylene/propylene oxide adducts as detergents and emulsifiers for ultimate use in cosmetics and light‐duty and heavy‐duty systems. Current estimated consumption of unsaturated alcohols in the USA is discussed.
Biodegradation of nonionic surfactants
Authors: Birch R. R.
Published: July 2007

This paper discusses the biodegradability of alcohol‐based nonionics measured by the recommended legislative test procedures and how the results obtained are affected by the chemical structure of the surfactant, and thus provides guidance on the selection of materials. More detailed studies on the biodegradation of alcohol ethoxylates during the activated sludge sewage treatment process are also reported. Examination of a wide range of alcohol ethoxylates in the legislative tests shows that the majority of those nonionics of practical importance will be extensively biodegraded. Although the mathematical model used to design the treatability test is very simple and has frequently come under criticism, the predictions seem to be upheld and the results obtained appear to provide a reliable guide to what is likely to happen in practice. The sludge residence time, which has long been regarded as of particular importance by those involved in the field of sewage treatment, is clearly demonstrated to be a highly significant factor whose influence should be taken into account in any detailed laboratory study of treatability. The study of alcohol ethoxylates indicates that extensive primary biodegradation will occur even in overloaded treatment plants where sludge retention times (SRT) are likely to be short. The effect of temperature on the biodegradation is small and suggests that effective treatment will be achieved in such plants even at the lower temperatures experienced during winter. Ultimate biodegradation of alcohol ethoxylates was shown to be extensive under practical conditions and levels of “polyethylene glycol” intermediates discharged to surface waters will be low. Although alcohol ethoxylates are rapidly and extensively absorbed on activated sludge, this does not play a significant role in the removal process which is essentially one of biodegradation.
Manufacture of fatty alcohols based on natural fats and oils
Authors: Kreutzer Udo R.
Published: July 2007

The present worldwide capacity of fatty alcohols is ca. 1.0 million metric tons per year. About 60% of this capacity is based on petrochemical feedstocks, 40% on natural fats and oils. Three basic dominating commercial‐scale processes are used to manufacture fatty alcohols: the Ziegler process and the Oxo synthesis starting from petrochemical feedstocks, and the high‐pressure hydrogenation of natural fatty acids and esters. Basically, the high‐pressure hydrogenation can be used with triglycerides, fatty acids or fatty acid esters as feedstock. The direct hydrogenation of fats and oils has not been developed to a commercial‐scale process, mainly because it was not possible to prevent decomposition of the valuable byproduct glycerol. Conversion of fatty acids into fatty alcohols by catalytic hydrogenation without preesterification requires corrosion‐resistant materials of construction and acid‐resistant catalysts. Required reaction temperatures are higher, resulting in a higher hydrocarbon content. The majority of fatty alcohol plants based on natural fats and oils use methyl esters as feedstock. These can be made either by esterification of fatty acids or by‐transesterification of triglycerides. For catalytic high‐pressure hydrogenation of methyl esters to fatty alcohols, several process options have been developed. The bawic distinguishing feature is the catalyst application either in a fixed bed arrangement or suspended in the methyl ester feed.
West European household detergent trends
Authors: Solleveld E.
Published: July 2007

It is estimated that there will continue to be a relatively strong growth in demand for alcohol derivatives, ca. 3 times as high as that for the product sector as a whole. Detergent alkylate growth will be somewhat lower, but it will remain the staple diet of the industry and by far the single largest volume detergent intermediate.
Cationic surfactants in laundry detergents and laundry aftertreatment aids
Authors: Puchta Rolf
Published: July 2007

Cationic surfactants have a positively charged nitrogen atom and at least one hydrophobic, long‐chain substituent in the molecule. Because of their fabric‐softening and antistatic properties, they are used as active materials in fabric‐softening agents. Suitable cationic surfactants are mostly quaternary ammonium salts, and to a lesser extent, imidazolinium salts with two long hydrophobic alkyl chains. Alkylated, partly ethoxylated polyamines, amine amides, ester amines and di‐quaternary compounds also have recently been used or proposed. Fabric softeners generally are aqueous dispersions of distearyl dimethyl ammonium chloride or tallow alkylated imidazolinium derivatives in concentrations of 1–9%. Concentrated fabric softeners have recently been pushed into the market as double, triple or 10‐fold concentrates. Fabric softeners used in the forms of acrosol sprays, pads or sheets, are not used in the washing machine but can be used in the laundry dryer. The combination of laundry detergent and fabric softener is a single product is impaired by anionic surfactants normally contained in laundry detergents because they react with the cationics to form neural salts. With the so‐called soft detergents, one attempts to circumvent these difficulties by means of special formulations, e.g., with nonionics or by using definite physical‐chemical mechanisms. They represent a compromise with regard to detergency performance and softening effect.
Column types for the chromatographic analysis of oleochemicals
Authors: Ottenstein D. M. , Witting L. A. , Silvis P. H. , Hometchko D. J. , Pelick N.
Published: July 2007

Chromatography has developed into one of the principle methods of analysis of oleochemicals. Gas chromatography has been used extensively for the analysis of long‐chain fatty acids as well as for the analysis of triglycerides and plant sterols. In recent years, high pressure liquid chromatography (HPLC) has been used for the analysis of triglycerides as well as for other related materials. Specialized gas chromatography columns have been developed for the separation of long‐chain fatty acids such as the methyl esters. These columns have generally used high polarity stationary phases which separate fatty acids by degree of unsaturation. A specialized use of these high polarity stationary phases is separation ofcis‐trans isomers as well ascis‐cis andtrans‐trans isomers. In this paper, packed and capillary columns are compared for the separation of thecis‐trans isomers of fatty acid methyl esters prepared from a hydrogenated vegetable oil. For HPLC separations, the presence of a double bond is approximately equivalent chromatographically to shortening the alkyl chain by two carbons. The long‐chain polyenic acids or ethyl esters thus elute near but are resolved from the short‐chain saturated fatty acids or esters. HPLC is the method of choice for relatively complex, high molecular weight, or labile esters, such as those of retinyl or cholesterol. Glyceryl esters are particularly well resolved by HPLC in terms of both total chain length and degree of unsaturation. This technique is also useful for lipid class separations and for the analysis of modified fatty acid products, such as prostaglandins and related materials. In general, these analyses are conducted with octadecyl bonded phase column packings.