Umweltverhalten und Toxikologie der Wachse

Environmental Behaviour and Toxicology of Waxes Plant and animal waxes are chemically relatively stable nontoxic substances and are used by humans since ages. In the nature waxes have protective function against environmental influences. This protective action is possible due to great resistance of the waxes towards environment, which also means low biological degradability. Obviously, waxes are undigestible and non-toxic in human and animal organism. Partially synthesized waxes based on montana wax, a plant fossil wax, have a structure similar to natural waxes, and therefore they resemble natural waxes with regard to environmental behaviour and are fully harmless from toxicological viewpoint. Also fully synthetic waxes, such as polyethylene waxes and polyethylene oxide waxes have, according to results obtained so far, no undesirable effects on environment. Waxes have been approved in foods worldwide, obviously due to their favorable toxicological properties.     

The composition of beeswax and other waxes secreted by insects

This review deals, with waxes of members of two quite different groups of insects, the bees and the scale insects, which secrete large amounts of wax. The former use was as a structural material and the latter as a protective material. The compositions of waxes from some of these insects are described and particular attention is paid to the compositions of the unhydrolyzed waxes and to the presence of hydroxy acids. New analyses of beeswax and of wax of a species of bumble bee are reported. The structures of the diesters, hydroxyesters and diols of beeswax are elucidated. The bumble bee wax contains major proportions of saturated and unsaturated hydrocarbons, and of long chain saturated, mono- and diunsaturated esters. The relationship between structure and function of the waxes is discussed. Issued as National Research Council of Canada No. 11260. One of six papers to be published from the Symposium on Natural Waxes, presented at the AOCS Meeting, San Francisco, April 1969.     

Host finding and oviposition behavior in a chrysomelid specialist--the importance of host plant surface waxes

Although several studies have elucidated the role of plant epicuticular waxes in host recognition and oviposition by herbivorous insects, there is little known about this subject in Chrysomelidae. In the present study, chemical cues for host recognition behavior and oviposition by the monophagous chrysomelid species Cassida stigmatica were investigated with special regard to surface waxes of the host plant, Tanacetum vulgare (Asteraceae). After hibernation in the soil, adults of this species must climb the plant's petioles, which emerge from the ground in spring. The response of adult C. stigmatica to contact and volatile cues from petioles and leaves of T. vulgare was investigated in a stem arena, in which differently treated petioles and petiole dummies were offered. Volatile and contact cues of T. vulgare petioles served as well for host recognition. The contact cues were isolated from the petioles and leaves by hexane extraction and by cellulose acetate treatment, which removed cuticular waxes. The attractive volatiles were not extracted sufficiently by hexane. To examine the role of cuticular waxes of the host leaf surface in oviposition, female C. stigmatica were offered intact leaflets and leaflets from which cuticular waxes had been stripped by cellulose acetate treatment. Females did not discriminate between intact and stripped leaflets when only the upper leaf surfaces were offered. However, when the lower leaf surfaces that are generally used as oviposition sites were offered, C. stigmatica preferred to lay eggs on intact leaflets. We conclude that waxes of the lower leaf surface contain crucial information for oviposition in C. stigmatica.     

Characterization of Oleogels Based on Waxes and Their Hydrolyzates

In this paper, the structuring of liquid oils, also known as oleogelation, is systematically investigated for the first time using a quasi-quaternary mixing system approach. Native waxes with different quantities of wax esters (WE), n-alkanes (hydrocarbons (HC)), fatty acids (FA), and fatty alcohols (FaOH) are applied in mixtures with hydrolyzed waxes to systematically change the composition. Hydrolyzed waxes contain high levels of FA and FaOH. The model systems are investigated on microscopic level (brightfield light microscopy (BFM), cryogenic scanning electron microscopy (cryo-SEM)) as well as on their macroscopic properties (rheology, gel hardness) and calorimetric behavior (differential scanning calorimetry (DSC)). It is found that sunflower wax (SFW)-based gels (12% structurant) become less hard on any admixture. Beeswax (BW)-based gels show significant increases in hardness when 25% and 50% (w/w) hydrolyzate are admixed. This could be related to stepwise crystallization. Further analysis reveals that the dissolution/melting behavior of the wax ester mixtures can be surprisingly well described as ideal solubility of a single pseudocomponent. The approach to unravel the individual contributions of the different species present in waxes is successful and marks a first step to better understand the systematic of wax functionality as oleogelators. Practical Application: The substitution of hardstock fats in structured oil phases is of interest for two reasons. The improved nutritional profile oleogels offer are beneficial for public health while the elimination of palm oil based ingredients appears to be a general public desire. Among the technical solutions for non-TAG oil structuring waxes are very promising. This is primarily due to their availability, prior consumption, potentially low cost for functionality. Currently waxes are technically and scientifically wrongly treated as single components. In order to better utilize the potential of waxes and design future sourcing strategies it is necessary to understand the wax functionality at a compositional/molecular level. This contribution marks the first step into this direction by considering classes of molecules with respect to their contribution to functionality. This understanding is considered as a key for future compositional design.     

Diesterwachse und ungewöhnliche Fettsäuren aus Bürzeldrüsenlipiden

Diester Waxes and Unusual Fatty Acids in Lipids of Sebaceous Gland Systematic investigations of lipids of sebaceous gland of birds have shown close relationship between the structure of these lipids and the individual species in the natural system of birds. In almost all the species studied so far the lipids of sebaceous gland consist of wax esters which are made up of unusual fatty acids and alcohols. Thus in the group of passeriformes (sparrows) 3-methyl substituted fatty acids, in the group of strigiformes (owls) 2-propyl and 2-butyl substituted fatty acids, and in the group of columbiformes (pigeons) 3-hydroxy fatty acids are found as constituents of the wax esters. Diester waxes are found in galliformes (hens), columbiformes, limicolae (snipes) and in some members of passeriformes. Unusual constituents of these waxes are alkanediols, 3-hydroxy fatty acids, and alkylhydroxymalonic acids. The structures were elucidated by a combination of GLC and mass spectrometry. Some of the mass spectra are discussed.     

Natural montan wax and its raffinates

Natural waxes have been used by mankind since prehistoric times. Many uses of wax are based on the imitation of its natural functions. Waxes in nature primarily serve to provide protective barriers on the surfaces of living organisms. Their functions are also determined by wax characteristics such as adhesion and cohesion, as well as slip and deformation effects. In ancient times, for example, wax seals were used to help preserve food and beverages. Beeswax has remained an important material for manufacturing candles up to the present day. Recent vegetable waxes have been used in industry since the mid‐nineteenth century, for example in care products. Refined and chemically processed montan‐based waxes are quite similar to naturally occurring vegetable ester waxes in their structure and application characteristics. They are similar in their environmental characteristics and are also nontoxic. Crude montan wax itself belongs to the naturally occurring waxes of vegetable origin such as candelilla wax and carnauba wax.     

Neuartige emulgierbare Polyäthylenwachse

Novel Emulsifiable Polyethylene Waxes In comparison to naturally occuring waxes and their derivatives, the group of synthetically prepared emulsifiable polyethylene waxes known so far exhibit a relatively small proportion of polar centers in their molecular structure. Using a new process of preparation, products having a high content of hydrophilic groups are obtained. The properties and emulsifying techniques are described. This report also includes the development of a new group of purely non-ionic emulsifiable very hard polymer waxes.     

Chemometric Classification of Comb and Cuticular Waxes of the Honeybee Apis Mellifera Carnica

Waxes are important as building material and for the chemical communication of the honeybee Apis mellifera carnica. In this study chemometric tools were established for classifying the different waxes inside the hive. By using gas chromatography in combination with mass spectrometry, components of different types of waxes were analyzed. By considering different substance classes of waxes, discriminant function analyses revealed distinct subtypes of comb waxes and of cuticular waxes. It is shown that the aging of comb wax is in part a spontaneous physicochemical process due to differential volatilities of compound classes with different chain length ranges. On the other hand it is directly influenced by the bees by adding lipolytic enzymes to the comb wax. The data suggest that the varying cuticular wax and comb wax compositions could serve as cues for bees to recognize castes, sexes, or comb age.     

Wax analysis of vegetable oils using liquid chromatography on a double-adsorbent layer of silica gel and silver nitrate-impregnated silica gel

A chromatographic method is described to measure the crystallizable wax content of crude and refined sunflower oil. It can also be applied to any other vegetable oil. The preparative liquid chromatography step on a glass column containing a silica gel adsorbent superimposed upon a silver nitrate-impregnated silica gel support is used to isolate a wax fraction which is then analyzed by gas chromatography. The recovered wax fraction contains, in addition to the crystallizable waxes, hydrocarbons and other compounds with gas chromatographic retention times corresponding to waxes with chain lengths C₃₄−C₄₂. These compounds are short-chain saturated waxes in fruit oils, such as grapeseed and pomace. In seed oils such as sunflower, soybean or peanut, the compounds initially referred to as “soluble esters” are identified as monounsaturated waxes, esters of long-chain saturated fatty acids, and a monounsaturated alcohol, mainly eicosenoic alcohol. Such waxes are absent from corn or rice bran oils.     

The Friction and Wear Behaviors of Vegetable Oil-Based Waxes,Natural Beeswax,and Petroleum Paraffin Wax

Quantitative analyses on the coefficient of friction of common coating waxes are necessary and essential for designing systems for coating, conveying, packaging operations, transporting, and storing of papers and paperboards, while analyses on wear behavior can be helpful for predicting performance durability of the coating surface. In this study, we investigated the friction and wear behaviors of six waxes including four commercial waxes and two soybean oil-based wax developed in our lab for bulk corrugated coating. The effect of normal load, sliding velocity, and environmental temperature was evaluated. The friction coefficient of different waxes varies with sliding conditions. Higher normal load, sliding velocity, and environmental temperature resulted in significantly greater wear loss. Crystalline morphology and crystallinity of waxes were affected by the environmental temperature, and they correlate to the variations in friction coefficient and wear loss of these materials.     

Studies of the refractive indices of binary wax mixtures

Summary The greatest deviations in refractive index from ideal behavior of the binary wax mixtures are obtained with mixtures of vegetable waxes. These are waxes with higher unsaturation, waxes containing a higher percentage of hydroxy esters, and waxes containing glycerides or combinations of these. Melting points and refractive indices at the melting points can be determined simultaneously with the Abbe-56 refractometer.     

A rapid,effective method for the reduction of waxes in sunflower seed oil

Four samples of sunflower seed were surface washed with boiling hexane to remove waxes and hydrocarbons. Measurement of waxes in oil extracted from washed and unwashed seed showed greater than 92% removal of waxes. In addition, straight chain hydrocarbon content of the oil was substantially reduced. The composition of the material removed is shown.     

Characterisation of waxes by differential scanning calorimetry

The characterisation of hydrocarbon and natural waxes by differential scanning calorimetry is described. It is shown that the determination of the melting, cooling and remelting curves of a wax, and comparison with the corresponding curves of authenticated waxes, affords a rapid and valuable method for the identification of many waxes. Heats of transition of many waxes are also given.     

A comparison of six solvents for the extraction of jojoba seed

Summary Data are presented which show the effects of different solvents on the yield and properties of liquid wax fromSimondsia chinensis (jojoba) and on the characteristics of the hydrogenated waxes obtained from the liquid waxes. Three reagent grade solvents, carbon tetrachloride, benzene, and isopropyl alcohol, and three commercial grade solvents, heptane, hexane, and tetrachloroethylene, were evaluated as extractants for the liquid wax from jojoba. Soxhlet-type of extractions were carried out under conditions in which the solvent was the only significant variable. Four of the solvents extracted essentially the same amount of material from the seed while isopropyl alcohol extracted significantly more material and tetrachloroethylene significantly less. Obviously the difficulties involved in separating the solids recovered from the isopropyl alcohol extraction preclude its use as the extracting solvent for jojoba wax. The density of the liquid waxes varies from 0.8631 to 0.8648; the waxes from the tetrachloroethylene and hexane extractions had the lowest value and the wax from isopropyl alcohol the highest. In each case, regardless of the solvent used, a precipitate developed in the liquid wax after it had been desolventized and stored for 7–10 days. Hydrogenation of clear fractions and precipitate containing fractions of these liquid waxes showed that the precipitate had no apparent effect upon the melting point or hardness of the resulting solid wax. Some of the liquid waxes required a longer hydrogenation time to attain an iodine value of about 1. At this iodine value all of the solid waxes had melting points between 66 and 68°C. Hardness values of all the solid waxes as measured by the Trionic hardness gauge were 90. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Monoterpenes and Epicuticular Waxes Help Female Autumn Gum Moth Differentiate Between Waxy and Glossy Eucalyptus and Leaves of Different Ages

The autumn gum moth, Mnesampela privata, is a native Australian species whose preferred host, Eucalyptus globulus (Myrtaceae), is an aromatic evergreen tree that has long-lived waxy leaves during the juvenile phase of growth. We compared the behavioral and antennal responses of female moths to whole leaves (new and old) and samples of foliar chemicals (from new and old leaves) from a typical E. globulus subsp. pseudoglobulus with responses to a glossy, half-sibling E. g. subsp. pseudoglobulus putative hybrid (the result of natural cross-pollination). We also studied larval survival and development on leaves from the same trees. In laboratory binary-choice assays, female M. privata laid more eggs on waxy leaves than on glossy leaves thereby confirming the nonpreference for the glossy tree that was observed in the field. Analyses of the monoterpenes and waxes of both trees revealed that they had comparable suites of monoterpenes and total oil contents but different suites of epicuticular waxes. Headspace extracts differed in the intensity of component monoterpenes. Gas chromatographic analyses with electroantennographic detection showed different patterns of monoterpene detection. Leaves of the glossy tree had a less diverse array of epicuticular waxes than those of the waxy tree. Electroantennographic screening of responses to wax extracts from leaves (new and old) from either tree revealed positive dose-dependent responses of female antennae to waxes from new leaves only. Binary-choice assays also revealed a strong preference by ovipositing females for new, compared to old, leaves whether they were from the waxy or the glossy tree. However, new leaves from either tree could be manipulated (by physical abrasion of epicuticular waxes) so that females would lay almost no eggs on them. Larval survival did not differ between groups reared on leaves from both trees (new and old). Over 70% of all larvae survived to pupation. However, larvae reared on leaves from the glossy tree took longer to pupate than those reared on leaves from the waxy tree. Also, larvae reared on new leaves from either tree did not perform as well as those reared on old leaves. Monoterpene and wax cues are suggested as helping female M. privata locate preferred hosts in native forests.     

A survey of some plant waxes of southern arizona

Summary The yield and characteristics of the waxes from 42 species of plants native to southern Arizona were determined. Although a few have high yields of wax when expressed on the basis of amount of wax per unit area of plant surface, the majority of species contains only a small amount of wax. It was concluded that the often quoted statement, “plants indigenous to arid and hot regions have waxy cuticles,” is untenable and should be modified to read “... waxlike cuticles.” Some taxonomic relationships and some effects of sex on plant waxes were discussed. This survey was supported by a grant from S. C. Johnson and Son Inc., Racine, Wis. Arizona Agricultural Experiment Station Technical Paper No. 453.     

Separation of some paraffin wax grades using solvent extraction technique

Solvent extraction technique has been used to separate paraffin wax grades; with different characteristics; from El-Ameria light, middle and heavy slack waxes. The wax deoiling has been done by solvent extraction at different extraction temperatures and different solvent feed ratios (S/F by weight). The extraction solvents used are furfural, N-methyl-2-pyrrolidone (NMP) and N, N, dimethylacetamide (DMA). The wax products are evaluated according to TAPPI-ASTM equation and petroleum wax specifications. The data revealed that DMA and NMP are suitable extracting solvents for isolating of semi- and scale-refined grades of paraffin waxes from light and middle slack waxes. But furfural solvent can separate only semi-microcrystalline waxes from heavy slack wax.     

Epichlorhydrin in der Wachssynthese

Epichlorohydrine in the Synthesis of Waxes Waxes that are soluble in usual wax solvents are of interest in special fields of application. It is not possible to prepare clear solutions of appreciable concentration using natural waxes, such as carnauba wax or derivatives of montana wax. Although these waxes are well soluble when hot, however, on cooling they separate out as crystalline or pasty masses. For preparing easily soluble waxes a new path of synthesis was found. Thus, waxes having ether or ester groups which were also easily soluble in the cold were prepared by reacting epichlorohydrine with such compounds, which, apart from having a long hydrocarbon chain also possessed a functional group with one active hydrogen atom.     

Über Modellwachse für den Metallpräzisionsguß

The Model Wax for the Precision Metal Castings After a short review of the history and the technique of precision metal casting on lost model waxes, the requisite properties of such waxes are given in details. The sum of all these properties can be achieved only by mixing different types of waxes with one another or by combination with other substances. At the same time, the molecular structure of the waxes also plays an important role. The relation between this and the shrinkage is shown by means of experimental investigations on a number of examples.