Formation of Engine-Deposit Compounds by Solid-State Reactions

Sonochemical synthesis of lead hydroxy bromide needles

“…Before discussing the DSC results, a brief description of the thermal behaviour of lead hydroxy bromide is given. 13,18,19 A study involving the dehydration and subsequent heat treatment of lead hydroxy bromide showed that PbO?PbBr 2 , the dehydration product, may exist in more than one crystalline form denoted as L, N and R. Each of the polymorphic forms react with water to produce the hydrate. The thermal relationships among these polymorphic forms are indicated below.…”

“…11,12 PbO?PbBr 2 based materials are found in automobile engine deposits and a study of these compounds is of fundamental signi®cance in understanding the nature of these deposits. 13 Increased focus on the preparation of materials through a surfactant-mediated process 14 led us to devise a new method, wherein elongated particles of Pb(OH)Br can be prepared in the presence of a cationic surfactant, cetyltrimethylammonium bromide (CTAB), [CH 3 (CH 2 ) 15 N(CH 3 ) 3 ]Br. This surfactant in water shows the presence of elongated thread-like micelles.…”

X-Ray Diffraction

“…X-ray studies have been carried out on cadmium iodide (123), the system of rubidium chloride and potassium bromide (122), the system of silver and copper mercuric iodides (107), and boron carbide (42). Engine deposits have been studied by x-ray examination of solid state reactions (69).…”

Dilatometric examinations of lead(II) oxychlorides

“…Only Ruer [11], examining phase dependences in the system PbO-PbC12, observed a thermal effect at 530~ in samples corresponding to the compound Pb5C1204. The authors of paper [12] found that PbzC120 occurs in three polymorphic modifications:…”