ALCOXYLATED AND CAPPED ALCOHOLS The present invention relates to the general field of alkoxylated alcohols, and more particularly alkoxylated and capped (or “capped”) alcohols, their method of preparation as well as their uses as surfactants. [0002] It is now known that alcohol alkoxylates represent a family of compounds offering a wide range of properties, with multiple applications, such as solvents, hydrotropic agents or surfactants. Thus, alcohol alkoxylates constitute a class of compounds of real industrial interest for a very large number of fields of application. [0003] Conventionally, alcohol alkoxylates are synthesized using basic catalysis, for example using potassium hydroxide, called “potash catalysis” or even “KOH catalysis”. For about ten years, however, another type of catalyst has been presented as being able to be used under certain conditions with certain reagents to obtain alkoxylates. This is the catalyst of the dimetallic cyanide type, also called DMC catalyst. [0004] Already in the 1960s, patent US3359331 dealt with the ethoxylation of alcohols using a catalyst based on tin and antimony. The catalyst was used in relatively large quantities, in a reaction medium at a temperature of less than 70° C. and at a pressure close to atmospheric pressure. This type of catalyst being very fragile, it was impossible to work in conventional reactors at the risk of deactivating the catalyst. Many years later, renowned researchers have published work (di Serio M. et al., Ind. Eng. Chem. Res., (1996), 35, 3848-3853) relating to the kinetics compared ethoxylation and propoxylation of 1- and 2-octanol by KOH catalysis. The authors conclude that KOH catalysis is not satisfactory and encourage the development of more efficient catalysts. [0006] More recently, international application WO2009000852 describes a process for the alkoxylation of various mobile H compounds, including alcohols, by DMC catalysis. This document teaches the need to add an oxypropylene (OP) and/or oxybutylene (OB) block to the starting substrate, before being able to graft an oxyethylene (EO) block, by DMC catalysis. The great majority of the substrates are alcohols of the Neodol type (poly branched alcohols obtained by the Fischer Tropsch process) and of the primary type. In addition the Catalyst concentrations used are high, about 3% by weight relative to the starting material. [0007] Similarly, international application WO2012005897 discloses the alkoxylation of alcohols by DMC catalysis, comprising firstly the addition of OP blocks, and only then the addition of OE blocks. [0008] The absence of large quantities of alcohol alkoxylates on the market today suggests that DMC catalysis today seems difficult to implement industrially, in particular on alcohol-type substrates, whereas this type of catalysis could make it possible to obtain alkoxylates with quite remarkable properties, in particular alcohol alkoxylates capped in the terminal position ("capped" or even "end-capped"). [0009] Certain terminally capped alkoxylates have already been described, such as those with benzyl termination in patent EP2205711, or those with carboxylic termination described in international application WO2004037960. It is well known that alkoxylation reactions lead to mixtures of alkoxylated products comprising a variable number of alkoxyl groups, the number of alkoxyl units in said mixture of alkoxylated products most often following a Gaussian distribution, more or less wide, or more or less narrow, generally characterized by the width of the Gaussian curve at mid-height, commonly quantified statistically by the value 2s. [0011] It has now been discovered, quite surprisingly, that it is possible to prepare, in a particularly easy manner on the industrial level, alcohol alkoxylates, capped in the terminal position, and which have properties quite interesting, in terms of physico-chemical properties as well as in terms of application properties. Thus and according to a first aspect, the present invention relates to a composition comprising a mixture of alcohol alkoxylates, end-capped, composition in which: - the alcohol comprises from 3 to 22, preferably from 5 to 22 carbon atoms, more preferably from 5 to 20, very particularly preferably from 5 to 18 carbon atoms, - the weight distribution of the alkoxylates follows a monomodal distribution whose peak width value (2s) is less than 7, preferably less than 6, advantageously less than 5, even more preferably less than 4, and - the terminal part is capped by a group chosen from linear or branched alkyls comprising from 1 to 6 carbon atoms, the phenyl group, the group benzyl, hydrocarbon groups bearing a carboxy -COO- function, and groups bearing a sugar unit. [0013] Preferably, the end cap of the alcohol alkoxylates is chosen from methyl, ethyl, propyl, butyl, benzyl and alkylcarboxyl-COOH groups and its salts. Among the possible salts of the carboxyl function, mention may be made of the salts well known to those skilled in the art and in particular the salts of metals, alkali metals, alkaline earth metals, ammonium, to cite only the main of them. Very particularly preferred salts are the sodium, potassium, calcium and ammonium salts. [0014] According to another embodiment, the end cap of the alcohol alkoxylates is chosen from alkylenecarboxyl and its salts, optionally functionalized. A typical and non-limiting example is represented by the sulfosuccinate group, and in particular sodium, potassium, calcium and ammonium sulfosuccinates. According to yet another embodiment, the end cap of the alcohol alkoxylates is chosen from groups bearing a sugar unit, such as for example glucose (case of monoglucosides), or two or more sugar units ( case of alkypolyglucosides, also called “APG”). As indicated above, the alcohol used as starting substrate for the alkoxylation reaction(s) comprises from 3 to 22, preferably from 5 to 22 carbon atoms, more preferably from 5 to 20 , most preferably from 5 to 18 carbon atoms. The carbon atoms can be straight chain, branched or partially or totally cyclic. According to a preferred embodiment, the alcohol has a weight-average molar mass ranging from 45 g mol 1 to 300 g mol 1 , preferably from 70 g mol 1 to 250 g mol 1 , more preferably from 80 g mol 1 at 200 g mol 1 . [0017] The alcohol used as starting substrate can be of all types and all origins. Generally the alcohol is a primary alcohol or a secondary alcohol. It may be of petroleum origin, or of bio-sourced origin, for example of plant or animal origin. An alcohol of bio-sourced origin is preferred, for obvious reasons of environmental protection. It is also preferred to use a secondary alcohol for the purposes of the present invention. When the alcohol is a primary alcohol, it can be chosen from linear or branched primary alcohols, for example from primary alcohols, linear or branched, comprising from 8 to 14 carbon atoms, for example 1 -octanol, 1-nonanol, 1-decanol, 1-undecanol, 1-dodecanol, 1-tridecanol, 1-tetradecanol, in particular alcohols with 10 carbon atoms, such as G Exxal™ 10, or even alcohols with 13 carbon atoms, such as G Exxal™ 13, marketed for example by Exxon Mobil. [0019] When the alcohol is a secondary alcohol, it can be chosen from secondary alcohols comprising from 3 to 22 carbon atoms, linear or branched, and optionally comprising one or more aromatic group(s), whose representatives can be phenolic alcohols, such as, for example, cardanol. According to a very particularly preferred aspect, the secondary alcohol contains from 3 to 22 carbon atoms, in an entirely advantageous manner from 3 to 14 carbon atoms, more preferably from 6 to 12 carbon atoms. Preferably again, the secondary alcohol is chosen from 2-octanol and 4-methyl2-pentanol, very particularly preferably, the secondary alcohol is 2-octanol. [0020] The alkoxylated repeating units are chosen from ethylene oxide, propylene oxide and butylene oxide units and mixtures thereof. Within the meaning of the present invention, the term “ethylene oxide unit” is understood to mean a unit derived from ethylene oxide after opening of the oxirane ring. Within the meaning of the present invention, the term “propylene oxide unit” is understood to mean a unit resulting from propylene oxide after opening of the oxirane ring. Within the meaning of the present invention, the term “butylene oxide unit” is understood to mean a unit resulting from butylene oxide after opening of the oxirane ring. According to one embodiment of the present invention, the capped alcohol alkoxylates comprise a sequence comprising one or more units chosen from the unit ethylene oxide, propylene oxide, butylene oxide and mixtures thereof, said units being distributed randomly, alternately or in blocks. According to another embodiment of the present invention, the capped alcohol alkoxylates comprise ethylene oxide units, and a sequence comprising one or more units chosen from the unit ethylene oxide, propylene oxide, oxide butylene and mixtures thereof, said units possibly being distributed randomly, alternately or in blocks, at least one propylene oxide or butylene oxide unit being present in said sequence. According to yet another preferred embodiment, the capped alcohol alkoxylates comprise at least one ethylene oxide unit and at least one propylene oxide unit, distributed alternately, randomly or in blocks. Still according to yet another preferred embodiment, the capped alcohol alkoxylates comprise at least one ethylene oxide unit and at least one butylene oxide unit, distributed alternately, randomly or in blocks. Another embodiment of the invention relates to capped alcohol alkoxylates comprising at least one propylene oxide unit and at least one butylene oxide unit, distributed alternately, randomly or in blocks. The number of repeating units is generally between, limits included, 1 and 100, preferably between 2 and 100, more preferably between 3 and 100, particularly between 3 and 80, more particularly between 3 and 75, preferably between 3 and 50, terminals included. According to a preferred embodiment of the present invention, the number of repeating units is between, limits included, 1 and 75, preferably between 2 and 75, more preferably between 3 and 75, particularly between 4 and 75 , more particularly between 5 and 75, preferably between 6 and 75, more preferably between 7 and 75, more preferably between 8 and 75, even more preferably between 9 and 75 and very preferably between 10 and 75. According to another preferred embodiment, the number of repeating units is between, limits included, 1 and 50, preferably between 2 and 50, more preferably between 3 and 50, particularly between 4 and 50, more particularly between 5 and 50, preferably between 6 and 50, more preferably between 7 and 50, more preferably between 8 and 50, even more preferably between 9 and 50 and very preferably between 10 and 50. According to yet another preferred embodiment, the number of repeating units is between, limits included, 1 and 30, preferably between 2 and 20, more preferably between 3 and 20, advantageously between 3 and 15. In the composition of the invention, the capped alcohol alkoxylates are present according to a monomodal weight distribution according to a normal law of statistical distribution. According to a very particular aspect of the present invention, the composition of secondary alcohol alkoxylates has a narrow monomodal weight distribution. In the present description and claims, the weight distribution is determined by analysis by gas chromatography on a standard column and flame ionization detection (FID) well known to those skilled in the art, where the various components of the compositions analyzed are separated by increasing boiling point and therefore by increasing molar mass by addition each time of an alkylene oxide unit. The weight distributions correspond to surface percentages assimilated to percentages by weight, on the assumption that the products have the same response coefficient, since they are of the same chemical nature. [0033] It has been discovered quite surprisingly that this very particularly narrow monomodal distribution of capped (or capped) alcohol alkoxylates present in the composition according to the present invention can be obtained using an alkoxylation reaction in the presence of a specific catalyst allowing very good control of the alkoxylation reaction, and in particular in the presence of a catalyst of dimetallic cyanide type (“DiMetallic Cyanide” or “DMC” in English). Other known catalysts and allowing access to mixtures of alkoxylates with narrow distribution ("narrow range distribution" in English language) can also be used, and as such one can quote, in a nonlimiting way, the acid catalysis of type derived from BF 3, calcium-based basic catalysis, hydrotalcite-type catalysts, and others. However, for the purposes of the present invention, catalysts of the DMC type, as indicated above, are preferred. [0034] It has in fact been observed that in the presence of such a specific so-called "narrow range" catalyst, the weight distribution of the alkoxylates is narrow, and quite particularly narrower than with a basic catalysis, of the catalysis type at potash. [0035] In addition to obtaining compositions with a very broad weight distribution, it is known that the substrate alkoxylation reactions, and in particular when the substrate is an alcohol, and very particularly when the alcohol is a secondary alcohol, for conventional routes (basic catalysis), leads to a very high residual of unreacted substrate. [0036] The capping reaction carried out on such compositions with a wide distribution and significant residual, can present difficulties of realization (reaction mediums which can be viscous making their handling difficult, insufficient yields, and others) and thus lead, in certain cases, to compositions of capped alkoxylates with application properties that are not very acceptable, or even mediocre. This is moreover very probably what explains why until now such capped alkoxylates have not been developed industrially at the present time. On the other hand, and this is one of the particular advantages of the present invention, the capped alcohol alkoxylates, and very particularly the capped secondary alcohol alkoxylates, described here have a tight distribution, and in a completely unexpectedly, greatly improved application performance. In particular when the compositions according to the present invention are used as surfactants, a lower foaming effect and better detergent performance can be observed, compared with the compositions known and available on the market today. It is also possible to obtain the compositions according to the present invention by carrying out the capping reaction described above directly on “narrow range” alkoxylates already commercially available. Among these “narrow range” alkoxylates, mention may be made, for example, of those of the Berol® range , marketed by the company Nouryon. Some of the capped alcohol alkoxylates described in this disclosure are new, and as such form part of the present invention. Thus, and according to another aspect, the invention relates to a composition comprising a mixture of capped 2-octanol alkoxylates with a narrow weight distribution, with a peak width value (2s) of less than 7, preferably less than 6, more preferably less than 5, most preferably less than 4. More specifically, the invention relates to a composition comprising 2-octanol alkoxylates capped with a group chosen from linear or branched alkyls comprising from 1 to 6 carbon atoms, the phenyl group, the benzyl group, hydrocarbon groups carrying a carboxy function -COO-, and the groups carrying a sugar unit, as defined above. [0042] Even more specifically, the present invention relates to a composition comprising - ethoxylated 2-octanol then capped with propylene oxide, - ethoxylated 2-octanol then capped with butylene oxide, - ethoxylated and/or propoxylated 2-octanol then capped by an alkyl group, in particular chosen from methyl, ethyl, propyl, butyl or even by a benzyl group, - ethoxylated and/or propoxylated 2-octanol then capped with a carboxyl (-(OH) h -OOOH, where n is an integer between 1 and 5, limits included, optionally in the form of an alkali salt, an alkali -terreux, or ammonium, preferably Na + , K + , NH 4 + ). According to a very particularly preferred aspect, the present invention relates to a composition comprising: - 2-octanol 2-15 EO 1 PO, - benzyl-capped 2-octanol 2-15 EO, - methyl-capped 2-octanol 2-15 EO, - 2-octanol 2-15 EO capped with ethyl, - propyl-capped 2-octanol 2-15 EO, - butyl-capped 2-octanol 2-15 EO, - 2-octanol 2-15 OE capped with CH 2 -COOH, - 2-octanol 2-15 OE 1-15 OB, - 2-octanol 2-15 EO 1-15 OP, - 2-octanol 1 -6 0E 1 -15 OP. The present invention also relates to a method for preparing the compositions according to the present invention as defined above, and comprising the following successive steps: a) reacting an alcohol with one or more alkylene oxides chosen from ethylene oxide, propylene oxide, butylene oxide and mixtures thereof, in the presence of at least one alkoxylation catalyst “narrow range” type, preferably DMC type; b) reacting the product from step (a) with one or more compounds capable of carrying out capping in the terminal position (“end-capping”). The alkoxylation of step a) can be carried out with one or more alkylene oxides, simultaneously, in sequence, or alternately, depending on the order of the alkoxylated units desired in the final composition. The alkylene oxides used in the process of the present invention can be of various origins, and in particular “mass balance” alkylene oxides, in particular “mass balance” ethylene oxide. , alkylene oxides of bio-sourced origin. Advantageously, the ethylene oxide used is of bio-sourced origin, for example the ethylene oxide can be obtained by oxidation of bio-sourced ethylene coming from the dehydration of bio-ethanol, itself coming from corn starch, lignocellulosic materials, agricultural residues such as for example sugar cane bagasse, and others. As indicated above, the alkoxylation reaction is carried out in the presence of a catalyst leading to a narrow weight distribution of the alkoxylates obtained, and preferably with the lowest possible residual alcohol. An entirely suitable catalyst belongs to the family of catalysts of the dimetallic cyanide type (“DiMetallic Cyanide” or “DMC” in English). Optionally, the product from step (a) can be isolated, although this is not necessary, in particular because the residual starting alcohol content is quite minimal and negligible. The alcohol used in step a) of the process of the invention can be any alcohol known to those skilled in the art, and in particular, is as described above, the alcohol is chosen from alcohols primary and secondary alcohols, preferably from secondary alcohols and preferably from 2-octanol and methylisobutylcarbinol, the preferred alcohol being 2-octanol. [0050] 2-octanol is in fact of very particular interest in several respects, in particular because it comes from a bio-sourced product and which does not compete with human or animal food. Furthermore, 2-octanol, which has a high boiling point, is biodegradable and has a good ecotoxicological profile. According to a preferred embodiment, the alcohol is used in step a) after drying, according to conventional techniques well known to those skilled in the art, from such that the water content in said secondary alcohol is less than or equal to 200 ppm, preferably less than or equal to 100 ppm. Preferably, the catalyst that can be used for the alkoxylation reaction of step a) of the process of the present invention can be any so-called "narrow range" catalyst known to those skilled in the art and in particular a catalyst of dimetallic cyanide (DMC) type. When the catalyst is of the dimetallic cyanide type, it can be of any nature well known to those skilled in the art, and as described for example in patents US6429342, US6977236 and PL398518. More particularly, the catalyst used comprises zinc hexacyanocobaltate and one or more ligands, for example the catalyst marketed by the company Covestro under the name Arcol ® or the catalyst marketed by the company Mexeo under the name MEO-DMC ® . Advantageously, the content of catalyst of the dimetallic cyanide type ranges from 1 ppm to 1000 ppm with respect to the starting alcohol content, preferably from 1 ppm to 500 ppm, preferably from 2 ppm to 300 ppm, more preferentially from 5ppm to 200ppm. The reaction can be carried out under any temperature and pressure conditions, as is well known to those skilled in the art, and according to a preferred embodiment, the reaction temperature during step (a) d the alkoxylation is generally between 80°C and 200°C, preferably between 00°C and 180°C. The reaction pressure during step (a) can range from 0.01 MPa to 3 MPa, preferably from 0.02 MPa to 2 MPa. Preferably, the method according to the invention comprises a step of eliminating the residual oxides used in the alkoxylation and/or capping step, more particularly the oxides of ethylene, propylene, butylene and their mixtures used during the process according to the invention. Thus, this step can take place after step (a) and/or after step (b), preferably after step a). Within the meaning of the present invention, the term “residual oxide” means an oxide which has not reacted. Preferably, said step of eliminating the residual oxide is carried out by cooking, that is to say by maintaining the temperature ranging from 70° C. to 170° C., preferably from 100° C. to 160° C., to consume the residual oxide, and/or by a step of stripping under a stream of inert gas. Alternatively, said stripping step can be carried out under reduced pressure. Preferably, after said elimination step, the mass content of residual oxide is generally less than or equal to 0.05% relative to the total weight of alkoxylates, capped or not, depending on whether this elimination step is carried out before or after step b), preferably less than or equal to 0.01%, more preferably less than or equal to 0.001%. The "end-capping" or capping reaction (step b) is carried out in a conventional manner, according to any method known to those skilled in the art, with or without a catalyst, and as for example described in the documents EP2205711 and WO2004037960 , cited above. In general, this capping reaction is carried out after formation of the alkoxide, in a basic medium (KOH, NaOH, for example), or else in the presence of a catalyst of the “narrow range” type, as described above, and in particular a catalyst of the DMC type, in particular when the capping is carried out using an alkylene oxide. Typically, the alkoxylate, or mixtures of alkoxylates, are reacted in the form of an alkoxide with a halide (for example alkyl, benzyl, w-halogenated carboxylic acid, and others) or else with an alkylene oxide . The reaction medium is then neutralized, the salt formed is filtered, the expected product is recovered. When it is chosen to carry out the capping reaction in the presence of a catalyst of the "narrow range" type, and in particular a catalyst of the DMC type, it may be advantageous to use the same catalyst as that used in the stage a), even without proceeding to a new addition of catalyst, and using the catalyst which was used during stage a). The method according to the present invention can be implemented in batch, semi-continuous or continuous. A person skilled in the art will be able to adapt the process for manufacturing the compositions according to the invention according to the random distribution, alternating or in blocks, of the sequences of alkoxylates desired. In addition, the method according to the invention has the advantage of synthesizing the capped alcohol alkoxylates under good safety conditions, so that it can be carried out on an industrial scale. Indeed, the operating conditions in terms of temperature and pressure are controlled thanks to the method according to the invention. In particular, the exothermicity of the reaction can be controlled very easily. The compositions of capped alcohol alkoxylates can most often be used as such, at the reactor outlet, without it being necessary to provide other purification, distillation or other steps. If necessary, conventional operations of filtration, drying, purification, and others, can be implemented. The present invention finally relates to the use of a composition of capped alcohol alkoxylates according to the present invention, as a surfactant, and in particular as a surfactant with low foaming power (“low-foaming surfactant” in English). Indeed, the compositions of the present invention which are characterized in particular by a narrow weight distribution, have very interesting application properties in terms of performance. Furthermore, the compositions of the present invention exhibit quite advantageous biodegradability profiles, in particular for low levels of alkoxylation (<8 units). [0064] The capped alcohol alkoxylates, and with a narrow weight distribution, make them compositions that are quite suitable in a very large number of fields of application, such as, for example, and in a non-limiting manner, for detergents, for cosmetic products, for ore flotation, as a lubricant, in particular for metal working fluids, as an emulsifier, as an adjuvant for bituminous applications, as as a wetting agent, as a solvent, as a coalescing agent, as a processing aid, for de-inking, as an anti-caking agent for hydrates gas, in enhanced oil and gas recovery applications, in corrosion protection,in hydraulic fracturing, in soil remediation, in agrochemicals (for example coatings of granular products, in particular fertilizers and phytosanitary products), but also as a hydrotropic agent, antistatic agent, paint adjuvant, textile adjuvant, for polyols, for the production of electrodes and electrolytes for batteries, to name only the main fields of application. The present invention further relates to a formulation comprising at least one composition of capped alcohol alkoxylates as defined above, and one or more aqueous, organic, hydro-organic solvents, chosen from water, alcohols, glycols , polyols, mineral oils, vegetable oils, waxes, and the like, alone or in mixtures of two or more of them, in all proportions. The formulation according to the invention may also contain one or more additives and fillers well known to those skilled in the art, such as, for example, and without limitation, anionic, cationic, amphoteric, non-ionic surfactants. , rheology modifiers, de-emulsifiers, anti-settling agents, anti-foaming agents, dispersants, pH control agents, colorants, antioxidants, preservatives, corrosion inhibitors, biocides, and other additives such as for example sulfur products , boron, nitrogen, phosphorus, and others. The natures and quantities of the additives and fillers can vary in large proportions depending on the nature of the application envisaged and can easily be adapted by those skilled in the art. The invention is now illustrated by the following examples which are in no way limiting. EXAMPLES The 2-octanol (CAS RN 123-96-6) used is Oleris® 2-octanol of “Refined” grade (purity >99%), marketed by Arkema France. Example A: Comparison between KOH catalysis and DMC catalysis To illustrate the narrow distribution effect obtained by DMC catalysis, in comparison with a basic catalysis with potassium hydroxide, an alkoxylation test of 2-octanol, at a rate of 1 mole of 2-octanol for 2 moles of propylene oxide, is carried out under the same operating conditions, on the one hand with a KOH catalyst and on the other hand with a DMC catalyst. In both cases, the 2-octanol is dried beforehand (to less than 1000 ppm for KOH and less than 200 ppm for DMC). The quantity of catalyst is equal to 2500 ppm of KOH on the one hand, and to 100 ppm of DMC on the other hand. The reaction is carried out in an autoclave under pressure of between 0.15 MPa and 0.6 MPa, at a temperature of between 130°C and 170°C. The results, in terms of weight distribution of the alkoxylation compounds determined by gas phase chromatography, and expressed as % of peak area of ​​each of the alkoxylates, are presented in Table 1 below: ~ Table 1: Weight distribution 2-octanol 2 OP - It can be seen with this example that in DMC catalysis the distribution is globally centered on a number of OP units equal to 2. It is also noted that the residual alcohol is significantly lower (Nbr OP = 0) in the case of the DMC catalysis than in the case of KOH catalysis. Furthermore, the 2s value calculated with the values ​​resulting from the basic catalysis is 5.0, whereas this 2s value calculated with the values ​​resulting from the DMC catalysis is 2.9. Example 1 Synthesis of 2-octanol 6 OE 4 OP in DMC catalysis In a 4 L autoclave, clean and dry, 750 g (5.76 M) of 2-octanol dried to less than 200 ppm of water and 0.11 g (150 ppm) of DMC Arcol catalyst are charged. ®. The reactor is closed again, purged with nitrogen and pressure tightness is checked. The reactor is pressurized with nitrogen. The reaction medium is initially brought to 90° C. with stirring. At a temperature of 120° C., 30 g of ethylene oxide are introduced. When the initiation of the reaction is observed, the balance of ethylene oxide is introduced, ie a total of 1520 g (34.56 M) for a period of 2 hours 50 minutes, at a temperature of approximately 140°C. At the end of the addition, the temperature is maintained for 30 min and then the residual ethylene oxide is stripped with nitrogen. The reactor is cooled to 80° C. and 1000 g of expected product are drawn off: 2-octanol 6 EO (IOH: 138 mg KOH/g and coloring at 77 Hz). Of the 1270 g (3.22 M) of 2-octanol 6 EO remaining in the reactor, 20 g of propylene oxide are introduced at a temperature of 130° G. When the initiation of the reaction is observed, the balance of the propylene oxide is introduced, ie a total of 747 g (12.9 M) for a period of 55 min at a temperature of approximately 140° C. At the end of the addition, the temperature is maintained for 30 min and then the residual propylene oxide is stripped with nitrogen. At the end of the reaction, 2015 g of 2-octanol 6 EO - 4 OP, clear, are recovered at 50° C. (IOH: 86 mg KOH/g and coloring at 10 Hz). Example 2: Synthesis of 2-octanol 6 OE - 4 OB by DMC catalysis In a 4 L autoclave, clean and dry, 500 g (3.84 M) of 2-octanol dried to less than 200 ppm of water and 0.075 g (150 ppm) of DMC Arcol ® catalyst are charged.. The reactor is closed again, purged with nitrogen and pressure tightness is checked. The reactor is pressurized with nitrogen. The reaction medium is initially brought to 90° C. with stirring. At a temperature of 120° C., 25 g of ethylene oxide are introduced. When the initiation of the reaction is observed, the balance of ethylene oxide is introduced, ie a total of 1015 g (23 M) for a period of 2 hours at a temperature of approximately 140°C. At the end of the addition, the temperature is maintained for 30 min and then the residual ethylene oxide is stripped with nitrogen. The reactor is cooled to 80° C. and 1000 g of product are withdrawn: 2-octanol 6 EO. (IOH: 140 mg KOH/g and 50 Hz staining). Of the 513 g (1.3 M) of 2-octanol 6 EO remaining in the reactor, 20 g of butylene oxide are introduced at a temperature of 130° C. When the initiation of the reaction is observed, the balance of the butylene oxide is introduced, ie a total of 375 g (5.2 M) for a period of 45 min at a temperature of approximately 140° C. At the end of the addition, the temperature is maintained for 30 min and then the residual butylene oxide is stripped with nitrogen. At the end of the reaction, 880 g of 2-octanol 6 EO - 4 OB, clear, are recovered at 50° C. (IOH: 81 mg KOH/g and coloring at 20 Hz). Example 3: Synthesis of 2-octanol 13 OE - benzyl ether in DMC catalysis In a 4 L autoclave, clean and dry, 500 g (3.84 M) of 2-octanol dried to less than 200 ppm of water and 0.075 g (150 ppm) of DMC Arcol ® catalyst are charged.. The reactor is closed again, purged with nitrogen and pressure tightness is checked. The reactor is pressurized with nitrogen. The reaction medium is initially brought to 90° C. with stirring. At a temperature of 120° C., 30 g of ethylene oxide are introduced. When the initiation of the reaction is observed, the balance of ethylene oxide is introduced, ie a total of 2200 g (50 M) for a period of 3 hours, at a temperature of approximately 140°C. At the end of the addition, the temperature is maintained for 30 min and then the residual ethylene oxide is stripped with nitrogen. The reactor is cooled to 80° C. and 2700 g of 2-octanol 13 EO product are withdrawn (IOH: 78 mg KOH/g and coloring at 20 Hz). The product is a white solid at room temperature. In a 4 L glass reactor, equipped with mechanical stirring, heating, a solid introduction funnel, a nitrogen inerting system, 2106 g (3 M) of 2-octanol 13 EO obtained previously as well as 10 g of water. The reaction medium is brought to 90° C. while bubbling with nitrogen in order to deoxygenate the medium. Nitrogen is then added to the top of the reactor and then 132 g (3.3 M) of sodium hydroxide in beads, ie 15% excess, are added. The medium is then brought to 100° C.-105° C. and under reduced pressure up to approximately 300 mbar, so as to distil the water. The stopping criterion is a water content <1.5%. The reaction medium is then brought back to 70° C., 342 g (2.7 M) of benzyl chloride are then added over about 60 min. The temperature is maintained for 5 hours at 120°C. After returning to 70°C, the reaction medium is neutralized with 37% hydrochloric acid until a pH of 7 is obtained. The water is distilled under reduced pressure to precipitate the sodium chloride formed. The latter is filtered and 2300 g of benzyl-capped 2-octanol 13 EO are recovered. Example 4: Synthesis of 2-Octanol 9 EO carboxylic ether in DMC catalysis In a clean and dry 4 L autoclave, 500 g (3.84 M) of 2-octanol dried to less than 200 ppm d water and 0.075 g (150 ppm) of DMC Arcol ® catalyst . The reactor is closed again, purged with nitrogen and pressure tightness is checked. The reactor is pressurized with nitrogen. The reaction medium is initially brought to 90° C. with stirring. At a temperature of 120° C., 25 g of ethylene oxide are introduced. When the initiation of the reaction is observed, the balance of ethylene oxide is introduced, ie a total of 1520 g (34.56 M) over a period of 2 hours 30 minutes, at a temperature of approximately 140°C. At the end of the addition, the temperature is maintained for 30 min and then the residual ethylene oxide is stripped with nitrogen. The reactor is cooled to 80° C. and 2010 g of 2-octanol 9 EO product are withdrawn (IOH: 105 mg KOH/g and coloring at 35 Hz). [0081] In a 3 L glass reactor, equipped with mechanical stirring, heating, a solid introduction funnel, a nitrogen inerting system, 1578 g (3 M) of 2-octanol 9 EO obtained previously. The reaction medium is brought to 50° C. while bubbling with nitrogen in order to deoxygenate the medium. Nitrogen is then added to the top of the reactor and then 126 g (3.15 M) of sodium hydroxide pearls are added. The water is distilled under reduced pressure. Then 367 g (3.15 M) of sodium mono-chloro-acetate are added at 50° C. At the end of the reaction, the reaction medium is neutralized with 37% hydrochloric acid. 1610 g of 2-octanol 9 EO carboxylic ether are recovered. Example 5: Synthesis of 1-decanol 5 OE by basic KOH catalysis 500 g (3.16 M) of 1-decanol of bio-sourced origin (marketed by Ecogreen) dried to less than 1000 ppm of water and 1 .5 g (3000 ppm) of potassium hydroxide (KOH) catalyst pellet. The reactor is closed again, purged with nitrogen and pressure tightness is checked. The reactor is pressurized with nitrogen. The reaction medium is initially brought to 90° C. with stirring. At a temperature of 120° C., 30 g of ethylene oxide are introduced. When the initiation of the reaction is observed, the balance of ethylene oxide is introduced, ie a total of 695 g (15.8 M) for 1 hour at a temperature of approximately 140° C. At the end of the addition, the temperature is maintained for 30 min and then the residual ethylene oxide is stripped with nitrogen. Example 6: Synthesis of 1-decanol 5 EO by DMC catalysis 500 g (3.16 M) of 1-decanol of bio-sourced origin (marketed by Ecogreen) dried to less than 200 ppm of water and 0.075 g (150 ppm) of DMC catalyst (sold by the company Mexeo). The reactor is closed again, purged with nitrogen and pressure tightness is checked. The reactor is pressurized with nitrogen. The reaction medium is initially brought to 90° C. with stirring. At a temperature of 120° C., 35 g of ethylene oxide are introduced. When the initiation of the reaction is observed, the balance of ethylene oxide is introduced, ie a total of 695 g (15.8 M) for 1 hour at a temperature of approximately 140° C. At the end of the addition, the temperature is maintained for 30 min and then the residual ethylene oxide is stripped with nitrogen. The reactor is cooled to 80° C. and 1185 g of 1-decanol product at 5 EO are withdrawn. (IOH: 145 mg KOH/g and 23 Hz staining). The results, in terms of weight distribution of the alkoxylation compounds determined by gas phase chromatography, and expressed as % of peak area of ​​each of the alkoxylates, are presented in Table 2 below: ~ Table 2: Weight distribution 1-decanol 5 EO - The 2s value calculated with the values ​​resulting from the basic catalysis is 7.3, whereas this 2s value calculated with the values ​​resulting from the DMC catalysis is 3.7. Example 7: Synthesis of 1-decanol 13 OE, benzylated, potash catalysis (KOH) Step a): Ethoxylation In a 4 L autoclave, clean and dry, 500 g (3.16 M) of bio-sourced 1-decanol (marketed by Ecogreen) dried to less than 1000 ppm of water and 1.5 g (3000 ppm) of solid KOH. The reactor is closed again, purged with nitrogen and pressure tightness is checked. The reactor is pressurized with nitrogen. The reaction medium is initially brought to 90° C. with stirring. At a temperature of 120° C., 30 g of ethylene oxide are introduced. When the initiation of the reaction is observed, the balance of ethylene oxide is introduced, ie a total of 1807 g (41 M) for 2 hours and 40 min at a temperature of approximately 140°C. At the end of the addition, the temperature is maintained for 30 min and then the residual ethylene oxide is stripped with nitrogen. The reactor is cooled to 80° C. and 2281 g of product 1-decanol 13 EO are withdrawn. (IOH: 77 mg of KOH/g and coloration of 480 Hz on the molten product). The product is a white solid at room temperature. Step b): Styling In a 4 L glass reactor, fitted with mechanical stirring, heating, a solid introduction funnel, a nitrogen inerting system, 2000 g (2.74 M) of 1-decanol 13 OE obtained in the preceding step, as well as 10 g of water. The reaction medium is brought to 90° C. under bubbling with azde in order to deoxygenate the medium. Nitrogen is then added to the top of the reactor and then 120 g (3 M) of sodium hydroxide in beads is added. The medium is then brought to 100° C.-105° C. under reduced pressure to approximately 30 kPa so as to distil the water. The stopping criterion is a water content of less than 1.5%. The reaction medium is then brought to 70°C. 329 g (2.6 M) of benzyl chloride are then added over about 60 min. The temperature is maintained for 5 hours at 120°C. After returning to 70°C, the reaction medium is neutralized with 37% hydrochloric acid until a pH of 7 is obtained. The water is distilled under reduced pressure to precipitate the sodium chloride formed. The latter is filtered and 2195 g of benzyl-capped 1-decanol 13 EO are recovered. Example 8: Synthesis of 1-decanol 13 OE, benzylated, DMC catalysis Step a): Ethoxylation In a 4 L autoclave, clean and dry, 500 g (3.16 M) of bio-sourced 1-decanol dried to less than 200 ppm of water and 0.075 g (150 ppm) of DMC catalyst are charged. Arcol® _. The reactor is closed again, purged with nitrogen and pressure tightness is checked. The reactor is pressurized with nitrogen. The reaction medium is initially brought to 90° C. with stirring. At a temperature of 120° C.,