Rhodium-Based Catalysts: An Impact of the Support Nature on the Catalytic Cyclohexane Ring Opening.

Because of the growing demand for high-quality fuels, the light cycle oil fraction improvement including cetane number improvement is important. The main way to reach this improvement is the ring opening of cyclic hydrocarbons, and a highly effective catalyst should be found. Cyclohexane ring openings are a possible option to investigate the catalyst activity. In this work, we investigated rhodium-loaded catalysts prepared using the commercially available industrial supports: single-component ones, SiO2 and Al2O3; and mixed oxides CaO + MgO + Al2O3 and Na2O + SiO2 + Al2O3. The catalysts were prepared by incipient wetness impregnation and investigated by N2 low-temperature adsorption-desorption, XRD, XPS, DRS UV-Vis and DRIFT spectroscopy, SEM, and TEM with EDX. The catalytic tests were performed in cyclohexane ring opening in the range of 275-325 °C. The best result was demonstrated by the sample 1Rh/CaMgAlO: the selectivity to n-hexane was about 75% while the cyclohexane conversion was about 25% at 275 °C. The space-time yield was up to 12 mmoln-hexane gcat-1h-1.

Facile Synthesis of Micro-Mesoporous Copper Phyllosilicate Supported on a Commercial Carrier and Its Application for Catalytic Hydrogenation of Nitro-Group in Trinitrobenzene.

Development of novel Cu-based catalysts has become one of the frontiers in the catalytic production of platform chemicals and in environment protection. However, the known methods of their synthesis are too complicated and result in materials that cannot be used instantly as commercial catalysts. In the present work, a novel material has been synthesized by the facile method of deposition-precipitation using thermal hydrolysis of urea. The conditions for Cu phyllosilicate formation have been revealed (molar ratio urea:copper = 10, 92 °C, 8-11 h). The prepared Cu-based materials were studied by TG-DTA, SEM, TEM, XRD, N2 adsorption and TPR-H2 methods, and it was found that the material involves nanoparticles of micro-mesoporous copper phyllosilicate phase with a chrysocolla-like structure inside the pores of a commercial meso-macroporous silica carrier. The chrysocolla-like phase is first shown to be catalytically active in the selective reduction of the nitro-group in trinitrobenzene to an amino-group with molecular hydrogen. Complete conversion of trinitrobenzene with a high yield of amines has been achieved in short time under relatively mild conditions (170 °C, 1.3 MPa) of nitroarene hydrogenation over a copper catalyst.

Ethanol to Acetaldehyde Conversion under Thermal and Microwave Heating of ZnO-CuO-SiO2 Modified with WC Nanoparticles.

The nonoxidative conversion of ethanol to acetaldehyde under thermal and microwave heating was studied on mixed oxide ZnO-CuO-SiO2 catalysts modified with additives of tungsten carbide nanoparticles. The results revealed that the WC-modified catalyst exhibited superior activity and selectivity under microwave heating conditions. It is assumed that when microwave heating is used, hot zones can appear at the contact points of WC nanoparticles and active centers of the mixed oxide ZnO-CuO-SiO2 catalyst, which intensively absorb microwave energy, allowing the more efficient formation of acetaldehyde at moderate temperatures. Thermodynamic calculations of equilibrium concentrations of reagents and products allowed us to identify the optimal conditions for effective acetaldehyde production. The initial catalyst and the catalyst prepared by the coprecipitation of the oxides with the addition of WC were characterized by physicochemical methods (TPR-H2, XRD, DRIFTS of adsorbed CO). The active centers of the oxide catalyst can be Cu+ cations.

Rectus Abdominis Endometrioma after Caesarean Section.

Isolated rectus abdominis muscle endometriosis is very uncommon with less than 20 case reports being published to date since its first description in 1984 by Amato and Levitt. We report another case of isolated rectus abdominis endometriosis in a 37-year-old patient with a previous caesarian section. We also discuss the diagnostic and treatment particularities in these patients. In our case, the treatment was only surgical and currently the patient is disease-free during the 24-month follow-up.

Torsion of an appendiceal mucinous cystadenoma. Report of a case and review of literature.

Vermiform appendix torsion is rare, and even more uncommon is the volvulus of appendiceal mucinous tumors. To our knowledge, only nine cases of torsion of the vermiform appendix associated with appendiceal mucinous neoplasms have been reported up to date. We report a case of secondary torsion of the vermiform appendix with mucinous cystadenoma in a 30-year-old man. The symptoms were consistent with acute appendicitis. Diagnostic laparoscopy revealed a mucinous tumor of the appendix with a 360 degrees twisted appendix. In order to avoid peritoneal dissemination open appendectomy was performed. The final pathologic diagnosis was a mucinous cystadenoma of the appendix. The postoperative recovery was uneventful. Secondary torsion of vermiform appendix with mucinous cystadenoma is a rare entity. Correct preoperative diagnosis is unlikely. Open appendectomy is the standard of care for benign mucinous appendiceal tumors. Furthermore, it is important to prevent spillage of the appendiceal mucocele content.

Appendiceal mucinous cystadenocarcinoma with implantation metastasis to the incision scar and cutaneous fistula.

INTRODUCTION: Mucinous cystadenocarcinoma of the appendix with invasion of the anterior abdominal wall and cutaneous fistula development is a rare condition. To the best of the authors' knowledge, five such cases have been reported in the medical literature. METHODS AND RESULTS: The patient was a 68-year-old man who presented with a mass growing through the incisional scar and a skin fistula with mucinous discharge 1 year after appendectomy via McBurney's incision. Carcinoembroyonic antigen and carbohydrate antigen 19-9 concentration was elevated. Abdominal computed tomography scan revealed a mass in the cecum with involvement of the abdominal wall. Right hemicolectomy with en bloc abdominal wall implant and skin fistula resection with clear margins was performed. DISCUSSION: The patient received intraperitoneal intra- and postoperative chemotherapy. Gross examination of the specimen showed a mass emerging from the remnant stump of the appendix. The patient showed no relapse 1 year after surgery. Clinical, paraclinical features, and treatment options are discussed with review of the literature.

Non-operative treatment for gall-stone ileus - a case report.

Gall-stone intestinal obstruction (GSO) is an unusual form of mechanical obstruction and a rare complication of cholelithiasis. The treatment options are controversial, usually the management is surgical but associated with significant morbidity and mortality. A spontaneous evacuation of the gall-stone that had induced GSO is even more exceptional, only few reports being published up to date. We report the case of an 81-year-old female patient presenting GSO admitted to our department due to abdominal pain and vomiting. Computed tomography revealed pneumobilia, distention of the ileum and a calcified mass in the small bowel lumen. The diagnosis of GSO was established, but since the gall-stone was <25 mm and severe cardiorespiratory co-morbidities conservative treatment was initiated and spontaneous evacuation of the gall-stone was obtained. Diagnostic and management modalities of GSO as well as literature reviews are reported.

Acute spontaneous chylous peritonitis: report of a case.

Acute abdominal pain with peritonitis due to sudden extravasation of lymph into the peritoneal cavity is a rare condition that is often mistaken for other causes of acute abdomen. The diagnosis of spontaneous chylous peritonitis is rarely suspected preoperatively, usually misdiagnosed with diverse common surgical emergencies. We report the case of an 81 year old female who presented with typical symptoms of acute abdomen, presumed as acute mesenteric ischemia. The diagnosis of chylous peritonitis was established during laparoscopy and treatment consisted of low fat diet and octreotide.

Liposarcoma of the colon: a case report and review of literature.

Liposarcoma is a malignant mesenchymal tumor frequently located in the retroperitoneum and rarely presents as an isolated lesion in the colon. To our knowledge, only three cases of primary colon liposarcoma have been reported in the world literature to date. In this article, we report a case of liposarcoma of the colon in a 46-year-old man. The patient presented with abdominal pain and a palpable mass. Abdominal ultrasonography and computed tomogram confirmed the presence of a large intra-abdominal fatty tissue mass, but the colon origin of the tumor was revealed only on laparotomy. During surgery, a voluminous (12 cm x 11 cm x 10 cm) lesion situated in the subserosa of the ascending colon was found, and a right hemicolectomy with radical lymph node dissection was performed. The pathological diagnosis of the resected tumor revealed primary colon liposarcoma (myxoid subtype). The postoperative course was uneventful, and the patient remained free of disease for 12 months. No adjuvant therapy was performed. Diagnostic and therapeutic problems related to this type of neoplasm as well as literature reviews are reported. Curative R0 resection remains the main treatment for primary and recurrent liposarcomas.

Gallbladder varices.

Gallbladder varices are relatively rare ectopic varices in patients with portal hypertension. We present here a case of gallbladder varices accurately diagnosed by color Doppler sonography. A 51-year-old woman was admitted to our unit with recurrent esophageal varices bleeding due to extrahepatic portal vein occlusion after splenectomy. Bleeding was controlled by endoscopic band ligation and esophageal varices were eradicated after the second endoscopic session. Doppler imaging showed the existence of portal cavernoma and gallbladder varices. The close follow-up period after complete eradication of esophageal varices showed no enlargement of varices of the gallbladder or complications related to them. Color Doppler sonography is a valuable noninvasive imaging technique for assessment of portal hemodynamic profile in patients with portal cavernoma as well as useful in detecting gallbladder varices. Preoperative correct diagnosis of gallbladder varices should increase the surgeon's vigilance during biliary tract surgery in patients with portal hypertension in order to avoid hazardous complications.

Extra-adrenal nonfunctional retroperitoneal paraganglioma: case report and review of the literature.

An extra-adrenal paraganglioma is a rare tumor derived from the chromaffin cells of sympathetic ganglia. This report documents a rare case of nonfunctional extra-adrenal paraganglioma in a 20-year-old woman with persistent flank pain. Ultrasonography and computed tomography revealed a solid mass with calcification in center, measuring 7 x 6 x 6 cm, and localized in the left upper para-aortal retroperitoneal region. Absence of typical clinical symptoms made a correct preoperative diagnosis unlikely. Tumor was successfully removed through a midline laparotomy incision, and pathological analysis of the surgical specimen revealed a paraganglioma. After 12 months, the patient is still in a good health, asymptomatic, and without evidence of tumor recurrence. This case emphasizes the necessity to include extra-adrenal paraganglioma in the differential diagnosis and management of retroperitoneal tumors, despite its rarity.

Giant submucosal lipoma of the cecum: report of a case and review of literature.

Lipoma of the colon is a relatively rare benign tumor. A case with intermittent subacute colon obstruction due to a giant lipoma of the cecum is reported. A 51-year-old woman presented with intermittent, abdominal crampy pain in the right upper and lower quadrants, accompanied by alternative episodes of diarrhea and constipation. She had had similar symptoms over the last three months. A double-contrast barium enema showed a large (approx. 7 cm in diameter) polypoid mass occluding the lumen of the cecum and the ascending colon. Colonoscopy revealed a submucosal mass suspected of benign tumor but too large for endoscopic resection. Surgery revealed a hard elongated mass in the right colon, which telescoped into the transverse colon and caused colo-colonic intussusception. Right hemicolectomy was performed and pathology documented a mature, submucosal lipoma of the cecum. Six years after the surgery, the patient has not showed any of the previous symptoms. Along with a review of the literature, the incidence, diagnosis complications and treatment of colonic lipomas are discussed.