The invention relates to a mixture of polyoxymethylene dialkyl ethers (POM) having a specific molecular distribution of n as well as its preparation method.The invention also relates to a composition comprising:a) a mixture of polyoxymethylene dialkyl ethers (POM) having a restricted specific molecular distributionb) at least one biocidal agentc) at least one pro-penetrating agentd) at least one dyee) optionally, another additiveand water as diluent,It also relates to a non-therapeutic method of preserving and/or embalming a dead human or animal body using the composition, such as the use of this composition for anatomopathological purposes.
